Electronic Structure Component for Logically Connecting Qubits

Abstract

An electronic structure component (10, 110, 210, 310, 410) for logically connecting qubits of a quantum computer is formed by a semiconductor component or a semiconductor-like structure. It comprises a substrate (12) with a two-dimensional electron gas or electron hole gas and gate electrode assemblies (116, 118, 120) having gate electrodes (122, 124, 126, 128), which are arranged on a surface (14) of the electronic structure component (10, 110, 210, 310, 410). Electrical contacts connect the gate electrode assemblies (116, 118, 120) to voltage sources. The gate electrodes (122, 124, 126, 128) of the gate electrode assemblies (116, 118, 120) have parallel electrode fingers (132, 134, 136, 138).

Description

TECHNICAL FIELD

The disclosure relates to an electronic structure component for logically connecting qubits of a quantum computer, which is formed by a semiconductor component or a semiconductor-like structure.

BACKGROUND

Conventional computers use semiconductor components with integrated circuits. These circuits always work with systems which are based on a logical “0” or “1”—i.e. the switch is “on” or “off”. In semiconductor memories, this is realized in that the potential is either above or below a threshold value. These two states form the smallest unit in computers and are referred to as “bits”.

These semiconductor components often consist of doped silicon elements in order to realize the circuits. For example, transistor circuits can be arranged in such semiconductor components and linked to form a logic circuit. Through continuously improving chemical and physical manufacturing processes, these semiconductor components can now be produced with increasingly extreme compactness. However, this compactness has reached its physical limits. The density of the circuits as well as the temperature often leads to problems in such semiconductor components. In this manner optimizations in particular can be achieved through several layer models, higher switching speeds, or the selection of the semiconductor material. Nevertheless, the computing power is often insufficient for many applications, e.g. in cryptographic technology or when calculating weather or climate models, due to the enormous amounts of data.

To significantly increase computing power, models for so-called quantum computers have long been known. For a variety of reasons, though, it has not yet been technically possible to implement them. The models of quantum computers are designed to exploit the quantum mechanical states of particles such as electrons. A quantum mechanical system with two states as the smallest unit for storing information is referred to as a “qubit”. A qubit is defined, for example, by its quantum mechanical spin state, which can be “up” or “down”.

The principle of electron spin qubits is always the same, regardless of the material system selected. A semiconductor heterostructure serves as the substrate in this case. The semiconductor heterostructure comprises a two-dimensional electron gas (2DEG). Semiconductor heterostructures are monocrystalline layers of semiconductors with different compositions grown on top of each other. These layer structures provide numerous technically relevant quantization effects in terms of their electronic and optical properties. For this reason, they are particularly suitable for use in the production of microelectronic components. Currently, the most important combination of materials for the production of semiconductor heterostructures is the GaAs/AlGaAs system.

Semiconductor heterostructures form so-called quantum films at the interfaces between different materials. These arise in particular because of the different energy levels in the two materials. The defined energy distribution resulting therefrom causes charge carriers from the surrounding area to collect in the quantum film. Their freedom of movement is largely restricted to the layer, and they form the two-dimensional electron gas (2DEG).

A nanoscopic material structure is referred to as a quantum dot. Semiconductor materials are particularly suitable for this. The mobility of the charge carriers, both electrons and holes, is so restricted in a quantum dot that their energy can no longer assume continuous values, and can thus only assume discrete values. Using nanoscale gate electrodes (also referred to as gates), which are applied to the surface of the component, the potential landscape within the two-dimensional electron gas (2DEG) is shaped in such a manner that individual electrons can be captured in the quantum dots. The spins of these electrons then serve as the basis for the formation of a logical qubit.

Electronic states can be split with regard to their spin state by means of an external magnetic field (Zeeman effect) and thus addressed separately. The spins of these electrons then serve as the basis of eigenstates for the purpose of forming a logical qubit. Furthermore, superimposed states of these two eigenstates can also be realized due to quantum mechanical effects.

Methods for manipulating single qubits via electron spin resonance (ESR) or electron dipole spin resonance (EDSR) are known. Two-qubit operations are known via exchange interaction.

US 2017/0317203 A1 discloses a quantum dot device comprising at least three conductive layers and at least two insulating layers. The three conductive layers are electrically insulated from one another. It is described there that one conductive layer is composed of a different material than the other two conductive layers. The conductive layers can include or be composed entirely of aluminum, gold, copper, or polysilicon, for example. The insulating layers, on the other hand, are composed of silicon oxide, silicon nitride, and/or aluminum oxide, for example. The connections between the conductive layers and the insulating layers can cause, inter alia, individual electrons to be shuttled through quantum dots of the device using voltage pulses.

In this quantum dot device, an electron is confined in a potential well. Through quantum mechanical tunneling, an electron is moved from quantum dot to quantum dot. This can lead to inaccuracies or falsifications of the information regarding the quantum mechanical state when an electron moves over longer distances.

WO 2017/020095 A1 discloses a scalable architecture for a processing device for performing quantum processing. The architecture is based on full-silicon CMOS fabrication technology. Transistor-based control circuits are used together with floating gates to operate a two-dimensional array of qubits. The qubits are defined by the spin states of a single electron, which is trapped in a quantum dot. A higher level is described here, meaning how individual qubits can be electrically driven, for example via transistors, etc., including qubit operation and readout. Although reference is made to a “scalable architecture”, the array shown does not allow any real scaling, meaning inter alia integration of cryogenic electronics, since no space can be created between the qubits.

U.S. Pat. No. 8,164,082 B2 describes a spin bus quantum computer architecture comprising a spin bus, which comprises a plurality of strongly coupled and always on qubits defining a string of spin qubits. A plurality of information-bearing qubits are arranged adjacent to a qubit of the spin bus. Electrodes are formed to the information-bearing qubits and the spin bus qubits to allow control of the establishment and breaking of coupling between qubits in order to allow control of the establishment and breaking of coupling between each information-bearing qubit and the spin bus qubit adjacent to it. The spin bus architecture allows rapid and reliable long-range coupling of qubits.

EP 3 016 035 B1 describes a processing apparatus and methods to operate the same, and particularly, but not exclusively, the invention relates to a quantum processing apparatus which is controllable to perform adiabatic quantum computations.

A quantum processor has the following features: a plurality of qubit elements and a control structure comprising a plurality of control members, wherein each control member is arranged to control a plurality of qubit elements. The control structure is controllable to perform quantum computation using the qubit elements, wherein a quantum state of the qubit elements is encoded in the nuclear or electron spin of one or more donor atoms. The donor atoms are arranged in a plane embedded in a semiconducting structure. A first set of donor atoms is arranged to encode quantum information related to the quantum computation.

A second set of donor atoms is arranged to facilitate electromagnetic coupling between one or more of the first set of donor atoms. The donor atoms of the first set are arranged in a two-dimensional matrix arrangement. The plurality of control members comprises a first set of elongated control members arranged in a first plane above the plane comprising the donor atoms. A second set of elongated control members are provided which are arranged in a second plane below the plane comprising the donor atoms.

In WO 2018/062991 A1, logical 0 and 1 states are realized in multi-qubit structures by means of the physical connection and implementation of suitable interactions between physical qubits. These structures are called logical qubits and are less susceptible to errors and/or less susceptible to external influences in terms of the storage of information. In order to be able to detect and correct errors in principle, so-called ancillary qubits, which are referred to in the following as parity qubits, are also used. A qubit whose proper state is determined with the aid of a parity qubit is referred to in the following as a data qubit.

Regulations, so-called surface codes, for implementing algorithms on a quantum computer, which are defined sequences of interactions on a two-dimensional lattice of data and parity qubits, are known from the New Journal of Physics 14 (2012) 123011. In order to implement complex algorithms, the interaction between data and parity qubits also needs to be precisely controlled and selectively switched on and off. This method is called ‘lattice surgery’ and corresponds to the embedding of defects in a crystal lattice.

DE 10 2019 202 661 A1 describes a method and a device for detecting the state of a data qubit with the aid of a parity qubit, wherein both types of qubits are initially positioned at a large distance from one another and can be moved and brought into contact in order to further reduce the error rate of a quantum computer.

To implement a universal quantum computer with the ability to implement logic circuits, it must be possible to couple the qubits over distances of at least a few micrometers, in particular to create space for local control electronics. Structures and structural elements must be provided which allow a quantum dot to be transported to different targets in order to be able to construct logic circuits. There are already approaches in the state of the art in which one or two-dimensional arrays were built from separate quantum dots, through which electrons can then be transported. Due to the very large number of gate electrodes required and corresponding voltages to be set, coupling over several micrometers is impossible to implement or can only be implemented with significant effort using this approach.

While operations on individual qubits can already be checked and evaluated to a satisfactory extent, the ability to connect qubits to form logic circuits is possibly the main problem still to be solved in order to realize a universal quantum computer. Definable quantum mechanical states must be present in order to realize such logic circuits.

SUMMARY

An object of the disclosure is to eliminate the disadvantages of the prior art and to provide an electronic structure component which allows logic circuits to be realized.

The object is achieved by an electronic structure component for logically connecting qubits of a quantum computer, which is formed by a semiconductor component or a semiconductor-like structure, comprising

• • a) a substrate with a two-dimensional electron gas or electron hole gas;
  • b) gate electrode assemblies having gate electrodes, which is arranged on a surface of the electronic structure component;
  • c) electrical contacts for connecting the gate electrode assemblies to voltage sources;
  • d) gate electrodes of the gate electrode assemblies having parallel electrode fingers.

Therein, the logical connection of functional components have gate electrode assemblies for generating static and/or moving potential wells and/or potential barriers for processing quantum dots in the substrate.

The disclosure is based on the principle that a structure for semiconductors is provided, which enables logical processing of operations with qubits. This structure requires functional elements that carry out the logic operations. With the present invention, gate electrode assemblies are arranged on the semiconductor in such a manner that they form functional elements with which such logical operations can be executed.

An advantageous embodiment of the structure component is based on the principle that, by means of a functional element, a quantum mechanical state is set in a quantum dot, which can then be transported through the substrate over a longer distance.

Preferably, the quantum dot is confined for this purpose in the potential well, which is generated in a suitable manner by the gate electrode assembly. The potential well then moves continuously and in a directed manner through the substrate and carries the quantum dot with its quantum mechanical state over the distance. To enable continuous movement of the potential well, the electrode fingers of the gate electrodes are connected accordingly. With the present function element, a quantum mechanical state of a quantum dot can thus be moved over a greater distance.

In a preferred embodiment of the electronic component, a gate electrode assembly comprises two parallel gate electrodes, which form a channel-like structure. This measure serves to ensure that the potential well can only move along a certain path in the substrate.

In an advantageous embodiment of such an electronic component, the substrate comprises gallium arsenide (GaAs) and/or silicon germanium (SiGe). These materials are able to form a two-dimensional electron gas in which quantum dots can be generated and moved. In the case of gallium arsenide, the quantum dots are occupied by electrons. In the case of silicon germanium, the quantum dots are occupied by holes that are missing an electron.

In a further preferred embodiment of the electronic component, the respectively interconnected gate electrodes are configured such that a periodic and/or phase-shifted voltage can be applied to them. This measure enables the potential well to be guided continuously through the substrate. A quantum dot located in the potential well can thus be transported through the substrate with the potential well while retaining its original quantum mechanical state.

In a preferred embodiment of the electronic component, at least every third electrode finger of a gate electrode is connected together. This is to ensure that the potential well is always guaranteed over at least one period through which the potential well is moved. Only in this way is it possible to ensure continuous movement of the potential well with the quantum dot. In principle, other combinations are also possible when interconnecting gate electrodes, as long as the potential well can be moved together with the quantum dot. Correspondingly, an advantageous embodiment for the method for an electronic component is obtained in that at least every third gate electrode is connected together and a voltage is applied periodically to the interconnected gate electrodes.

In a further advantageous embodiment of the electronic structure component, means are provided for connecting two qubits of a quantum computer. Transporting the states of quantum dots over greater distances is particularly suitable for quantum computers. In quantum computers, it is necessary to connect qubits to one another. For this reason, the electronic component must provide contacts to connect at least two qubits to one another in order to transfer the quantum states of the quantum dots from one qubit to another qubit.

In an advantageous embodiment of the structure component, a functional element is provided for diverting the motion of a quantum dot.

With such an intersection or branch, it is possible using quantum dots to realize circuits not previously possible. As a result of such an electronic component, logic circuits can now be built in quantum computers. With this component, it is possible to interconnect logic circuits.

Preferably, the functional element for branching comprises a first and a second branching gate electrode assembly with gate electrodes in different directions, wherein the electrode fingers of the gate electrodes are interconnected in a periodically alternating manner, which causes an almost continuous movement of the potential well through the substrate, whereby a quantum dot is transported with the potential well of the first gate electrode assembly in one direction, and the quantum dot can be moved from the first potential well to the second potential well of the second branching gate electrode assembly with a different direction of travel.

The function element is based on the principle that a quantum mechanical state is set in a quantum dot, which can then be transported through the substrate over a longer distance. For this purpose, the quantum dot is confined in the potential well, which is generated in a suitable manner by the gate electrode assembly. The potential well then moves continuously and in a directed manner through the substrate and carries the quantum dot with its quantum mechanical state over the distance. To enable continuous movement of the potential well, the electrode fingers of the gate electrodes are connected accordingly. At the branch, the quantum dots are deflected to a potential well of a branching gate electrode assembly. The quantum dot must be moved in order to go in the other or a new direction. With the present invention, a quantum mechanical state of a quantum dot can thus be moved and a connection established over a greater distance.

In an advantageous embodiment of such an electronic structure component, a third gate electrode assembly is provided for generating a switchable potential barrier arrangement in the region of the branch, which is switched for the transfer of the quantum dot. This potential barrier arrangement prevents the quantum dot from moving in a direction other than the direction prescribed by the branch. Depending on how the potential barrier arrangement is switched, the quantum dot is redirected with the potential well into the one or the other branching direction. In this manner, it is in particular also possible to realize complex circuits with changes in direction.

In a further advantageous embodiment of the electronic structure component, means for synchronizing the gate electrode assemblies are provided to change the direction of the quantum dot at the branch. The transfer of the quantum dot at a branch requires very precise coordination of the gate electrodes so that the potential well also actually transfers the quantum dot. The measure presented here thus serves to provide means for controlling the gate electrodes which connect the gate electrode assemblies synchronously to one another so that a coordinated change in direction becomes possible.

In a preferred embodiment of the electronic structure component, a gate electrode assembly comprises two parallel gate electrodes, which form a channel-like structure. This measure serves to ensure that the potential well can only move along a certain path in the substrate.

In a further advantageous embodiment of the electronic structure component, a function element is provided for manipulating qubits in quantum dots. A quantum mechanical state at a quantum dot can be set with the functional element. The quantum mechanical state defined in this manner can then be transported through the substrate over a longer distance.

Preferably, the function element has a manipulator in a manipulation zone that sets the qubit of the quantum dot to a definable quantum state, wherein the manipulation zone is provided in the adjacent region, which is formed by the first and second gate electrode assembly. In general, qubits are realized by electron spins. The function element also utilizes the fact that a quantum mechanical state is set for a quantum dot by the manipulator in the manipulation zone. The quantum mechanical state defined in this manner can be transported through the substrate over a longer distance. For this purpose, the quantum dot is confined in the potential well, which is generated in a suitable manner by the gate electrode assembly. The potential well then moves continuously and in a directed manner through the substrate and carries the quantum dot with its quantum mechanical state over the distance. To enable continuous movement of the potential well, the electrode fingers of the gate electrodes are connected accordingly. A quantum dot is transported to the static potential well in the manipulation zone via the movable potential wells.

In an advantageous embodiment of the electronic structure component, the manipulator comprises means for a switchable magnetic field in the area of the manipulation zone for the purpose of manipulating the qubit. The magnetic field serves to split the electronic states with respect to the spin. These new eigenstates thus serve as a basis for forming a logical qubit.

In a further advantageous embodiment of the electronic structure component, the manipulator comprises means for generating an oscillating magnetic field or a gradient magnetic field in the manipulation zone. An electron is located in an in-plane magnetic field gradient, whereby the magnetic field gradient is used to be able to switch between the eigenstates split with respect to the spin.

A preferred embodiment of the electronic structure component is obtained in that the manipulator contains a microwave generator, which radiates microwaves into the manipulation zone for the purpose of manipulating the quantum dot. This measure serves to allow a quantum dot to be moved in the manipulation zone until a desired quantum state has been set. Microwaves are irradiated via a gate electrode, for example. These microwaves distort the potential in a controlled manner so that an electron begins to oscillate in a controlled manner in the magnetic field. Due to spin-orbit coupling, it is then possible to switch between the two spin states.

In a particular variant of the electronic structure component, the manipulator comprises a third gate electrode assembly with gate electrodes for transporting a quantum dot by means of a potential well, which is arranged adjacent to a surface of the electronic structure component and to the manipulation zone. As a result, two quantum dots can be transported simultaneously to the manipulation zone.

In a further advantageous embodiment of the electronic structure component, a function element is provided for reading out the quantum state of a qubit in a quantum dot. This measure serves to enable quantum mechanical states to be read out during operations for logical interconnection.

Preferably, the gate electrodes of the gate electrode assemblies have parallel electrode fingers, whereby in a first gate electrode assembly the electrode fingers are periodically interconnected in an alternating manner, which brings about an almost continuous movement of the potential well through the substrate, whereby a first quantum dot is transported with this potential well, and the electrode fingers of a second gate electrode assembly form a static potential well in which a second charge carrier with a known quantum mechanical state is provided. A sensor element for detecting changes in the charge is provided, which detects the charge in the static potential well, wherein the first quantum dot is transported to the second quantum dot. The function element is based in principle on the physical Pauli Exclusion Principle, which states that an electron level can never be occupied by electrons with the same spin. By means of the gate electrodes, a static potential well is generated on the one hand and, on the other hand, a movable potential well. A quantum dot is introduced into the static potential well, the quantum mechanical state of which is known at one level, which in the case of an electron is the spin. A further quantum dot of the same level is introduced into the static potential well at by means of the movable potential well. If the quantum mechanical states are different, then the level is filled. In this case, the sensor element detects a charge change in this level. If the quantum mechanical states of the quantum dots are the same, then the level cannot accept another quantum dot. The quantum mechanical state therefore does not change in this level. As a result, it is possible to determine the quantum mechanical state of the quantum dot introduced.

In order to guide the quantum dot with the movable potential well to the static potential well, the quantum dot must be transported through the substrate over a longer distance without changing the quantum mechanical state. For this purpose, the quantum dot is confined in the potential well, which is generated in a suitable manner by the gate electrode assembly. The potential well then moves continuously and in a directed manner through the substrate and carries the quantum dot with its quantum mechanical state over the distance. To enable continuous movement of the potential well, the electrode fingers of the gate electrodes are connected accordingly.

In an advantageous embodiment of the electronic structure component, a magnetic field generator is provided for generating a gradient magnetic field in order to initialize the quantum mechanical state of the quantum dot of the static potential well. A gradient magnetic field or an oscillating magnetic field can be generated with a micro-magnet, for example. These magnetic fields place the quantum dot in a desired quantum mechanical state. The electronic structure component can thus be initialized so that it is then able to interact with the quantum dot introduced into the same level.

In a preferred embodiment of the electronic component, a second gate electrode assembly comprises two gate electrodes, which together form a static double potential well, wherein each of the static potential wells has a quantum dot with different quantum mechanical states. In this case, each of the potential wells is occupied by known quantum mechanical states, which in the case of electrons are the spins. In this case, the charge carrier of one of the quantum dots, which are held in the double potential well, exchanges with the charge carrier of the moved quantum dot. As a result, the moved quantum dot always placed in a defined quantum mechanical state since the quantum mechanical states of the quantum dots in the double potential well are known. The sensor element can now check on the static double potential well if there is a change in charge. This makes it possible to determine the quantum mechanical state of the introduced quantum dot.

In a further advantageous embodiment of the electronic structure component, a function element is provided for initializing the quantum state of a quantum dot.

Preferably, the functional element for initializing the quantum state of a quantum dot comprises a reservoir which is provided as a dispenser for charge carriers. The gate electrodes of the gate electrode assemblies have parallel electrode fingers, whereby the gate electrodes of a first gate electrode assembly in the substrate form a static double potential well or the gate electrodes of a first gate electrode assembly in the substrate form a static potential well, in which charge carriers are introduced from the reservoir into the quantum dots. The gate electrodes of a second gate electrode assembly form a movable potential well in the substrate, wherein a charge carrier with its quantum mechanical state can be transported with this potential well. Means for transferring two charge carriers from the reservoir into the static potential well are provided. Furthermore, a stimulator for orienting or splitting the quantum dots is provided. Means for transferring a charge carrier from the static potential well into the movable potential well are also provided. The function element for initializing the quantum state of a quantum dot is based in principle on the physical Pauli Exclusion Principle, which states that an electron level can never be occupied by electrons with the same spin. By means of the gate electrodes, a static potential well is now generated on the one hand and, on the other hand, a movable potential well. A pair of charge carriers from the reservoir and with the same energy level is introduced into the static potential well. The pair of charge carriers is subsequently split. The one quantum dot is transferred into the movable potential well. The quantum mechanical state of the quantum dots is oriented in a defined manner by the stimulator to the level, which in the case of an electron is the spin. The quantum dot having the known quantum mechanical state in the movable potential well can now be transported away, for example as an initialized qubit, with the movable potential well.

In order to guide the quantum dot with the movable potential well to the static potential well, the quantum dot must be transported through the substrate over a longer distance without changing the quantum mechanical state. For this purpose, the quantum dot is confined in the potential well, which is generated in a suitable manner by the gate electrode assembly. The potential well then moves continuously and in a directed manner through the substrate and carries the quantum dot with its quantum mechanical state over the distance. To enable continuous movement of the potential well, the electrode fingers of the gate electrodes are connected accordingly.

In an advantageous embodiment of the electronic component, the stimulator is designed as a magnet, which generates a gradient magnetic field for initializing the quantum dots in the static potential well. The quantum dots of an energy level are oriented in a defined manner depending on the orientation of the magnetic field. In the often small structures of this component, micro-magnets, which can be integrated easily into the semiconductor component, can preferably be used. The gradient magnetic field therefore serves to initialize the quantum dots in the static potential well. An oscillating magnetic field can also be used as a gradient magnetic field. These gradient magnetic fields place the quantum dot in a desired quantum mechanical state. The electronic component can thus be initialized so that it is then able to interact with the quantum dot introduced into the same level.

In a further advantageous embodiment of the electronic component, the gate electrodes of the first gate electrode assembly form a static double potential well, wherein means for transporting a quantum dot from the one static potential well into the next static potential well of the static double potential well are provided. Each of the static potential wells thus has a quantum dot with different quantum mechanical states of the same level. The defined orientation of the states is in turn determined by the stimulator. In this case, each of the potential wells is occupied by known quantum mechanical states, which in the case of electrons are the spins. One of the quantum dots held in the double potential well exchanges with the quantum dot of the moved potential well. As a result, the moved quantum dot obtains a defined quantum mechanical state.

Further embodiments and advantages will become apparent from the subject matter of the subclaims and the drawings with the accompanying descriptions. Exemplary embodiments are explained in more detail below with reference to the accompanying drawings. The invention should not be limited solely to the exemplary embodiments listed. The present invention is intended to refer to all objects that a person skilled in the art would deem obvious now and in the future to realize the invention. The following detailed description refers to the best embodiments currently possible of the disclosure. They are only intended to illustrate the invention in more detail. The description is therefore not to be understood in a limiting sense, but is merely intended to illustrate the general principles of the invention since the scope of the invention is best defined by the appended claims. The prior art cited is considered part of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic top view of an exemplary embodiment of an electronic structure component for logically connecting the qubits of a quantum computer.

FIG. 2 shows a section according to FIG. 1.

FIG. 3 shows a schematic top view of a first exemplary embodiment of an electronic component, which has a branch.

FIG. 4 shows a section of the branch according to FIG. 11 and the path of movement of a quantum dot in the branch.

FIG. 5 shows a schematic top view of a section of an exemplary embodiment of an electronic component with a gate arrangement for manipulating the quantum state of a quantum dot or a charge carrier.

FIG. 6 shows a schematic diagram of the sequence of manipulation in the manipulation zone of a variant with gate electrode assemblies provided on both sides for two movable potential wells for single qubit operations.

FIG. 7 shows a schematic diagram of the sequence of manipulation in the manipulation zone of a variant with gate electrode assemblies provided on one side for one movable potential well for single qubit operations.

FIG. 8 shows a schematic diagram of the sequence of manipulation in the manipulation zone of a variant for two-qubit operations.

FIG. 9 shows a schematic top view of the electronic component for reading out the quantum state of a quantum dot with a static potential well.

FIG. 10 shows a schematic diagram of the sequence of an electronic component for reading out the quantum state of a quantum dot with a static potential well.

FIG. 11 shows a schematic top view of the electronic component for reading out the quantum state of a quantum dot with a static double potential well.

FIG. 12 shows a schematic diagram of the sequence of an electronic component for reading out the quantum state of a quantum dot with a static double potential well.

FIG. 13 shows a schematic top view of the electronic component for initializing the quantum state of a quantum dot with a static double potential well.

FIG. 14 shows a section of a schematic diagram of an exemplary embodiment of an electronic component with a double potential well for initializing and reading out a qubit.

FIG. 15 shows a section of a schematic diagram of an exemplary embodiment of an electronic component with a double potential well for initializing a qubit.

FIG. 16 shows a schematic top view of the electronic component for initializing the quantum state of a quantum dot with a static potential well.

FIG. 17 shows a section of a schematic diagram of an exemplary embodiment of an electronic component with a potential well for initializing a qubit.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary embodiment of an electronic structure component 10, which is formed from a semiconductor heterostructure. Undoped silicon germanium (SiGe) is used as the substrate 12 for the electronic structure component 10. The electronic component 10 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). Functional elements 16, 18, 20, 22, 24 are provided on a surface 14 of the substrate 12. The electronic structure component 10 comprises at least one unit cell 26.

The unit cell 26 comprises the various functional elements 16, 18, 20, 22, 24. The functional element 16 comprises a transport function for moving a quantum dot in the substrate. The functional element 18 serves as a branch point so that branches 28 can be made possible in a logic circuit. The functional element 20 is provided for manipulating qubits in quantum dots. The functional element 20 can set a quantum mechanical state in a quantum dot. The quantum mechanical state thus definable can then be transported through the substrate 12 with the functional element 16 or 18 over a longer distance in the structure of the electronic structure component 10. For logical operations, it is necessary on the one hand to occupy quantum mechanical states, and on the other hand to read out quantum mechanical states. The functional element 22 serves to define quantum mechanical states. For this purpose, it manipulates a qubit in its quantum dot. The quantum state of a quantum dot can be defined with this functional element 22. Correspondingly, the functional element 24 serves to read out the quantum dot. The functional element 24 serves to initialize the quantum state of a quantum dot.

Whole structures of an electronic component 10 for logic circuits of a quantum computer can be designed with these unit cells 26.

FIG. 2 shows the unit cell 26. The unit cell 26 comprises the functional element 16 for the movement of a quantum dot, the functional element 18 for the branch, the functional element 24 for the manipulation of a qubit, the functional element 24 for reading out a qubit, and the functional element 26 for the initialization.

FIG. 3 shows an exemplary embodiment of an electronic component 110, which is formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 112 for the electronic component 110. The electronic component 110 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). Gate electrode assemblies 116, 118, 120 are provided on a surface 114 of the substrate 112.

The gate electrode assemblies 116, 118 each have two gate electrodes 122, 124, 126, 128. The individual gate electrodes 122, 124, 126, 128 are electrically isolated from one another in a suitable manner with insulating layers 130. The gate electrode assemblies 116, 118, 120 are structured in layers, wherein the insulating layer 124 is provided between each gate electrode 122, 124, 126, 128. The gate electrodes 122, 124, 126, 128 further comprise electrode fingers 132, 134, 136, 138, whereby each of the gate electrodes 122, 124, 126, 128 is arranged parallel to another on the surface 114 of the substrate 112.

The gate electrode assemblies 116, 118, 120 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 122, 124, 126, 128 of the gate electrode assemblies 116, 118, a potential well is generated in the substrate 112. A quantum dot trapped in this potential well can thus be transported through the substrate. The potential well is transported longitudinally through the substrate through suitable control of the electrode fingers 132, 134, 136, 138 with sinusoidal voltages. The quantum dot confined in such a potential well can be transported with this potential well over a greater distance in the two-dimensional electron gas of the substrate 112 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 118 branches off from the gate electrode assembly 116 in an intersection area 140. The gate electrode assembly 120 is arranged in the intersection area 140. In the present exemplary embodiment, the gate electrode assembly 120 contains two barrier gate electrodes 142, 144. These barrier gate electrodes 142, 144 can be connected when the moving potential well with the quantum dot is located in the intersection area 140. By connecting the barrier gate electrodes 142, 144, the potential well with the quantum dot is held in the intersection area 140. A pump gate electrode 146 of the gate electrode assembly 120 causes the potential well with the quantum dot to change direction and move toward the gate electrode assembly 118.

If no change in direction is to be performed by the potential well with the quantum dot, then a barrier gate electrode 148 of the gate electrode assembly 120 is switched on. The other two barrier gate electrodes 142, 144 are correspondingly switched off. The barrier gate electrode 148 blocks access to the gate electrode assembly 118. The quantum dot in the moving potential well is therefore not induced to change direction.

FIG. 4 schematically illustrates a section through such an electronic component 110. A sequence of positions A to C of a movable potential well 150 with a quantum dot 152 is shown below the section of the component 110. In the illustration of the electronic component 110, only sectional diagrams of the electrode fingers 136, 138, the barrier gate electrodes 148, and the pump gate electrodes 146 are visible. Sequences from A to C of the positions of the potential well 150 in the substrate 112 are shown below this. The electrode fingers 136, 138 of the gate electrode assemblies 118 form the movable potential wells 150 through the substrate 112. The movement of the potential well 150 is effected by appropriately interconnecting the electrode fingers 126, 128. The electrode fingers 136, 138 of the gate electrode assembly 116 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential well 150 through the substrate 112. In the present figure, it is illustrated how the potential well 150 with the quantum dot 152 branches off the intersection area 140. The movable potential well 150 is located in the direction of the branching gate electrode 118. The arrow 154 symbolizes the direction in which the potential well 150 moves with the quantum dot 152.

FIG. 5 shows a first exemplary embodiment of an electronic component 210, which is formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 212 for the electronic component 210. The electronic component 210 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). Gate electrode assemblies 216, 218 are provided on a surface 214 of the substrate 212.

The gate electrode assemblies 216, 218 each have two gate electrodes 220, 222, 224, 226. The individual gate electrodes are electrically isolated from one another in a suitable manner with insulating layers 227. The gate electrode assemblies 216, 218, 240 are provided in layers, wherein an insulating layer 227 is provided between each gate electrode assembly. The gate electrodes 220, 222, 224, 226 further comprise electrode fingers 228, 230, 232, 234, which are arranged parallel to another on the surface 214 of the substrate 212.

In an adjacent region 236 where the gate electrode assemblies 216, 218 adjoin, a manipulation zone 238 is formed. A manipulator 239, which contains a further gate electrode assembly 240, is located in the manipulation zone 238. The gate electrode assembly 240 comprises gate electrodes 242, 244, 246, which form at least one static potential well. The gate electrode assembly 240 further comprises pump gate electrodes 248, 250, which can set a quantum dot or a charge carrier in motion or in oscillation.

The gate electrode assemblies 216, 218, 240 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 220, 222, 224, 226 of the gate electrode assemblies 216, 218, a potential well is generated in the substrate 212. A quantum dot or charge carrier trapped in this potential well can thus be transported through the substrate. The potential well is transported longitudinally through the substrate through suitable control of the electrode fingers 228, 230, 232, 234 with sinusoidal voltages. The quantum dot or charge carrier confined in such a potential well can be transported with this potential well over a greater distance in the two-dimensional electron gas of the substrate 212 made of SiGe without experiencing a quantum mechanical change of state.

FIG. 6 shows a schematic diagram of the sequence of manipulation of a quantum dot or charge carrier 252, 254 in the manipulation zone 238 for a single qubit operation. The diagram shows a section of the electronic component 210 so that only the electrode fingers 228, 230, 232, 234; the barrier gate electrodes 242, 244, 246; and the pump gate electrodes 248, 250 are visible in the section. Sequences from A to F of the positions of the potential wells 256, 258, 260 in the substrate 212 are shown below this to explain the function. The electrode fingers 228, 230, 232 234 of the gate electrode assemblies 216, 218 form the movable potential wells 256, 258 through the substrate 212. The movement of the potential wells 256, 258 is effected by appropriately interconnecting the electrode fingers 228, 230, 232, 234. The electrode fingers 228, 230, 232, 234 of the gate electrode assembly 216, 218 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential wells 256, 258 through the substrate 212.

A static double well 260 is formed in the manipulation zone 238. The static double well 260 is produced by the barrier gate electrodes 242, 244, 246. First, a quantum dot 254 is brought with the movable potential well 258 into the static double potential well 260 in the manipulation zone 238. The quantum dot 254 can assume a defined quantum mechanical state by the manipulator 239, for example a gradient magnetic field. Another quantum dot 252 waits outside the manipulation zone 238. A defined quantum state of the quantum dot 254 is achieved through movement in the magnetic field gradient of the manipulator 239. It is now the possible to have the quantum dot 254 assume a defined quantum state through delocalization (E) or through rapid back and forth motions in the magnetic field gradient (F). The quantum dots 252, 254 brought out of the manipulation zone 238 assume defined quantum mechanical states in this manner.

FIG. 7 shows a schematic diagram of the sequence of manipulation of a quantum dot or charge carrier 254 in the manipulation zone 238 for a single qubit operation. The diagram shows a section of the electronic component 210 so that only the electrode fingers 232, 234; the barrier gate electrodes 242, 244, 246; and the pump gate electrodes 248, 250 are visible in the section. Sequences from A to F of the positions of the potential wells 258, 260 in the substrate 212 are shown below this to explain the function. The electrode fingers 232, 234 of the gate electrode assemblies 216, 218 form the movable potential well 258 through the substrate 212. The movement of the potential well 258 is effected by appropriately interconnecting the electrode fingers 232, 234. The electrode fingers 232, 234 of the gate electrode assembly 218 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential well 258 through the substrate 212.

The static double well 260 is formed in the manipulation zone 238. The static double well 260 is produced by the barrier gate electrodes 242, 244, 246. The quantum dot 254 is brought with the movable potential well 258 into the static double potential well 260 in the manipulation zone 238. The quantum dot 254 can assume a defined quantum mechanical state by the manipulator 239, for example a gradient magnetic field. It is now the possible to have the quantum dot 254 assume a defined quantum state through delocalization in the double well (E) or through rapid back and forth motions in the magnetic field gradient (F). The quantum dots 254 brought out of the manipulation zone 238 assume a defined quantum mechanical state in this manner.

FIG. 8 shows a schematic diagram of the sequence of manipulation in the manipulation zone 238 of a further variant for two-qubit operations. The diagram shows a section of the electronic component 210 so that only the electrode fingers 228, 230, 232, 234; the barrier gate electrodes 242, 244, 246; and the pump gate electrodes 248, 250 are visible in the section. Sequences from A to E of the positions of the potential wells 256, 258, 260 in the substrate 212 are shown below this to explain the function. The electrode fingers 228, 230, 232 234 of the gate electrode assemblies 216, 218 form the movable potential wells 256, 258 through the substrate 212. The movement of the potential wells 256, 258 is effected by appropriately interconnecting the electrode fingers 228, 230, 232, 234. The electrode fingers 228, 230, 232, 234 of the gate electrode assembly 216, 218 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential wells 256, 258 through the substrate 212.

The static double well 260 is formed in the manipulation zone 238. The static double well 260 is produced in this case as well by the barrier gate electrodes 242, 244, 246. The quantum dots 252, 254 are transported with the movable potential wells 256, 258 to the static double potential well 260 in the manipulation zone 238 and are each brought into the double potential well 260. The quantum dots 252, 254 can assume a defined quantum mechanical state by the manipulator 239, for example a gradient magnetic field. Via exchange interaction 264, two-qubit operations can be carried out between the quantum dots 252, 254. The quantum dots 252, 254 brought out of the manipulation zone 238 assume defined quantum mechanical states in this manner.

FIG. 9 shows a first exemplary embodiment of an electronic component 310, which is formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 312 for the electronic component 310. The electronic component 310 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). Gate electrode assemblies 316, 318 are provided on a surface 314 of the substrate 312.

The gate electrode assembly 316 has two gate electrodes 320, 322. The individual gate electrodes 320, 322 are electrically isolated from one another in a suitable manner with insulating layers 324. The gate electrode assemblies 316, 318 are provided in layers, wherein the insulating layer 324 is provided between each gate electrode 320, 322. The gate electrodes 320, 322 further comprise electrode fingers 326, 328, which are arranged parallel to another on the surface 314 of the substrate 312.

The gate electrode assemblies 316, 318 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 320, 322 of the gate electrode assembly 316, a potential well is generated in the substrate 312. A quantum dot or charge carrier trapped in this potential well can thus be transported through the substrate in this manner. The potential well is transported longitudinally through the substrate through suitable control of the electrode fingers 326, 328 with sinusoidal voltages. The quantum dot or charge carrier confined in such a potential well can be transported with this potential well over a greater distance in the two-dimensional electron gas of the substrate 312 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 316 forms a region in which a quantum dot can be transported by means of a potential well. The gate electrode assembly 318, on the other hand, forms a static potential well. The gate electrode assembly 318 comprises for this purpose barrier gate electrodes 330, 332 and a pump gate electrode 334, which can set a quantum dot or a charge carrier in motion or in oscillation. The pump gate electrode 334 is arranged between the barrier gate electrodes 330, 332. The gate electrodes 330, 332, and 334 are also separated from one another by an insulating layer 324.

The barrier gate electrode assembly includes a sensor element 336 for detecting changes in charge. The sensor element 336 detects the charge present in the static potential well. The potential well is generated by the gate electrode assembly 318.

FIG. 10 shows a schematic diagram of the sequence for reading out a quantum state of a qubit in a quantum dot 342. The diagram shows a section of the electronic component 310 so that only the electrode fingers 326, 328; the barrier gate electrodes 330, 332; and the pump gate electrodes 334 are visible in the section. Sequences from A to C of the positions of the potential wells 346, 348 in the substrate 312 are shown below this to explain the function. The electrode fingers 326, 328 of the gate electrode assembly 316 form the movable potential well 346 through the substrate 312. The movement of the potential well 342 is effected by appropriately interconnecting the electrode fingers 326, 328. The electrode fingers 326, 328 of the gate electrode assembly 316 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the quantum dot 342 through the substrate 312.

The electronic component 310 is based on the physical Pauli Exclusion Principle, which states that an electron level can never be occupied by electrons with the same spin. By means of the gate electrodes 330, 332, the static potential well 348 is generated on the one hand, and on the other hand, the movable potential well 346 is generated by means of the gate electrodes 326, 328. A quantum dot 342 is introduced into the static potential well 348, the quantum mechanical state of which is known in one level, which in the case of an electron is the spin. The quantum dot is oriented with the pump gate electrode 340, for example with spin up, as illustrated here. A further quantum dot 344 of the same level is introduced into the static potential well 348 by means of the movable potential well 346. The arrow 350 indicates the direction of transport of the quantum dot 344 with the movable potential well 346. If the quantum mechanical states are different, then the level is filled. The level can be filled by tunneling, which is symbolized by arrow 352.

In the event that a quantum dot has been added, the sensor element 336 detects a change in charge in this level. If the quantum mechanical states of the quantum dots 342, 344 are the same, then the level cannot accept another charge carrier 358. The quantum mechanical state therefore does not change in this level. As a result, it is possible to determine the quantum mechanical state of the quantum dot 342 introduced.

FIG. 11 shows a further exemplary embodiment of an electronic component 310, which is again formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 312 for the electronic component 310. The electronic component 310 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). The gate electrode assemblies 316, 318 are provided on the surface 314 of the substrate 312.

The gate electrode assembly 316 has two gate electrodes 320, 322. The individual gate electrodes 320, 322 are electrically isolated from one another in a suitable manner with insulating layers 324. The gate electrodes 320, 322 of the gate electrode assembly 316 are provided for this purpose in layers, wherein the insulating layer 324 is provided between each gate electrode 320, 322 of the gate electrode assembly 316. The gate electrodes 320, 322 further comprise the electrode fingers 326, 328, which are arranged parallel to another on the surface 314 of the substrate 312.

The gate electrode assemblies 316, 318 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 320, 322 of the gate electrode assembly 316, a movable potential well is generated in the substrate 312. A quantum dot 342 or charge carrier trapped in this potential well can thus be transported through the substrate in this manner. The potential well is transported longitudinally through the substrate through suitable control of the electrode fingers 326, 328 with sinusoidal voltages. The quantum dot 342 or charge carrier 358 confined in such a potential well can be transported with this potential well over a greater distance in the two-dimensional electron gas of the substrate 312 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 318 forms a static double potential well. The gate electrode assembly 318 comprises for this purpose barrier gate electrodes 330, 332, 338 and, in addition to the pump gate electrode 334, another pump gate electrode 340, which can set a quantum dot or a charge carrier in motion or in oscillation. The pump gate electrodes 334, 340 are alternately arranged between the barrier gate electrodes 330, 332, and 338.

The sensor element 336 for detecting changes in charge is adjacent to the barrier gate electrode assembly 318. The sensor element 336 detects the charge present in the static double potential well. The double potential well is generated by the gate electrode assembly 318.

FIG. 12 shows a schematic diagram of the sequence for reading out a quantum state of a qubit in the quantum dot 342. The diagram shows a section of the electronic component 310 so that only the electrode fingers 326, 328; the barrier gate electrodes 330, 332, 338; and the pump gate electrodes 334, 340 are visible in the section. Sequences from A to F of the positions of the potential wells 346, 348 in the substrate 312 are shown below this to explain the function. The electrode fingers 326, 328 of the gate electrode assembly 316 form the movable potential well 346 through the substrate 312. The movement of the potential well 346 is effected by appropriately interconnecting the electrode fingers 326, 328. The electrode fingers 326, 328 of the gate electrode assembly 316 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential well 346 through the substrate 312.

The electronic component 310 is based on the physical Pauli Exclusion Principle, which states that an electron level can never be occupied by electrons with the same spin. By means of the gate electrodes 330, 332, and 338, a static double potential well 362 is generated on the one hand and, on the other hand, the movable potential well 346. A charge carrier 358 is introduced into a first potential well 364 of the static double potential well 362. Two charge carriers 358 are split with the pump gate electrodes 334, 340, for example with the aid of a gradient magnetic field. A split charge carrier 360 tunnels into a second static potential well 366. A further quantum dot 342 is introduced into the second static potential well 366 of the double potential well 362 of the same level by means of the movable potential well 346. The arrow 350 indicates the direction of transport of the quantum dot 342 with the movable potential well 346. The quantum dot 360 of the second static potential well 366 exchanges with the quantum dot 342 of the movable potential well 346. The quantum mechanical state with the movable potential well 346 is known. The quantum dot 342, provided it has the same spin as the quantum dot 360, tunnels into the first static potential well of the double potential well 362. The sensor element 336 does not detect any change in charge. If the quantum mechanical states of the quantum dots 360 and 342 differ, then a change in charge is detected. The level can be filled by tunneling, which is symbolized by arrow 352.

FIG. 13 shows a further exemplary embodiment of an electronic component 410, which is again formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 412 for the electronic component 410. The electronic component 410 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). The gate electrode assemblies 416, 418 are provided on the surface 414 of the substrate 412.

The gate electrode assembly 416 has two gate electrodes 420, 422. The individual gate electrodes 420, 422 are electrically isolated from one another in a suitable manner with insulating layers 424. The gate electrodes 420, 422 of the gate electrode assembly 416 are provided for this purpose in layers, wherein the insulating layer 424 is provided between each gate electrode 420, 422 of the gate electrode assembly 416. The gate electrodes 420, 422 further comprise the electrode fingers 426, 428, which are arranged parallel to another on the surface 414 of the substrate 412.

The gate electrode assemblies 416, 418 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 420, 422 of the gate electrode assembly 416, a movable potential well is generated in the substrate 412. A quantum dot 442 or charge carrier trapped in this potential well can thus be transported through the substrate in this manner. The potential well is transported longitudinally through the substrate through suitable control of the electrode fingers 426, 428 with sinusoidal voltages. The quantum dot 442 confined in such a potential well can be transported with this potential well over a greater distance in the two-dimensional electron gas of the substrate 412 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 418 forms a static double potential well. The gate electrode assembly 418 comprises for this purpose barrier gate electrodes 436, 438, 440 and, in addition to the pump gate electrode 442, another pump gate electrode 444, which can set a quantum dot or a charge carrier in motion or in oscillation. The pump gate electrodes 442, 444 are alternately arranged between the barrier gate electrodes 436, 438, and 440. Each of the gate electrodes 436, 438, 440, 442, 444 has electrode fingers 437, 439, 441, 443, 445.

The barrier gate electrode assembly 418 is adjacent to the reservoir 449 for effecting changes in charge.

FIG. 14 shows a section of a first exemplary embodiment for an electronic component 410, which is formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 412 for the electronic component 410. The electronic component 410 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). Gate electrode assemblies 416, 418 are provided on a surface 414 of the substrate 412.

The gate electrode assembly 416 has two gate electrodes 420, 422. The individual gate electrodes 420, 422 are electrically isolated from one another in a suitable manner with insulating layers 424. The gate electrode assemblies 416, 418 are provided in layers, wherein the insulating layer 424 is provided between each gate electrode 420, 422. The gate electrodes 420, 422 further comprise electrode fingers 426, 428, which are arranged parallel to another on the surface 414 of the substrate 412.

The gate electrode assemblies 416, 418 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 420, 422 of the gate electrode assembly 416, a potential well 430 is generated in the substrate 412. A quantum dot 432 or charge carrier trapped in this potential well 430 can thus be transported through the substrate in this manner. The potential well 430 is transported longitudinally through the substrate through suitable control of the electrode fingers 426, 428 with sinusoidal voltages. The quantum dot 432 or charge carrier confined in such a potential well 430 can be transported with this potential well 430 over a greater distance in the two-dimensional electron gas of the substrate 412 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 418, on the other hand, forms a static double potential well 434. The gate electrode assembly 418 comprises for this purpose barrier gate electrodes 436, 438, 440 and two pump gate electrodes 442, 444, which can set a quantum dot 432, 450, 454 or a charge carrier in motion or in oscillation. The pump gate electrodes 442, 444 are alternately arranged between the barrier gate electrodes 436, 438, 440. The gate electrodes 436, 438, 440, 442, 444 of the gate electrode assembly 418 are also separated from one another by an insulating layer 424. Each of the gate electrodes 436, 438, 440, 442, 444 has electrode fingers 437, 439, 441, 443, 445. The electrode fingers 437, 439, 441, 443, 445 can be seen in this sectional drawing.

In this figure, the sequences in the substrate 412 of the electronic component 410 for initializing a quantum state of a qubit in a quantum dot are shown schematically below the gate electrode assemblies 416, 418. Sequences from A to F of the positions of the potential wells 430, 434 in the substrate 412 are shown below this to explain the function. The electrode fingers 426, 428 of the gate electrode assemblies 416 form the movable potential well 430 through the substrate 412. The movement of the potential well 430 is effected by appropriately interconnecting the electrode fingers 426, 428. The electrode fingers 426, 428 of the gate electrode assembly 416 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential well 442 through the substrate 412.

The electronic component 410 is based on the physical Pauli Exclusion Principle, which states that an electron level can never be occupied by electrons with the same spin. By means of the gate electrodes 436, 438, 440 and 442, 444, a static double potential well 434 is generated on the one hand, and on the other hand, the movable potential well 430 is generated with the gate electrodes 420, 422. Two charge carriers 448 from a reservoir 449 are introduced into a first potential well 446 of the static double potential well 434. The charge carriers 448 are split and oriented with a stimulator 451, for example with the aid of a gradient magnetic field and the pump gate electrodes 442, 444. A split charge carrier 450 tunnels into a second static potential well 452 of the double potential well 434, which is indicated by the arrow 453. Only one charge carrier 454 remains in the first static potential well. The quantum states of the quantum dots 450, 454 in the potential wells 446, 448 are known due to the orientation of an applied gradient magnetic field.

A further quantum dot 432 is introduced into the second static potential well 452 of the double potential well 434 of the same level by means of the movable potential well 430. The quantum mechanical state of the quantum dot 432 is not known. The arrow 458 indicates the direction of transport of the quantum dot 432 with the movable potential well 430. Due to the tunneling effect, the quantum dot 450 of the second static potential well 452 exchanges with the quantum dot 432 of the movable potential well 430. The quantum mechanical state of the quantum dot 450 is known, and it is now located in the movable potential well 430 and initializes, for example, a qubit.

The quantum dot 432, provided it has the same spin as the quantum dot 450 guided away for the purpose of initialization, tunnels again into the first static potential well 446 of the double potential well 434. A sensor element, which is not shown here, would therefore not detect a change in charge. If the quantum mechanical states of the quantum dots 450 and 432 differ, then a change in charge can be detected. The exchange is symbolized by arrow 460.

FIG. 15 shows a section of a further exemplary embodiment of the electronic component 410, which is formed from a semiconductor heterostructure. The structures of the component 410 are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 412 for the electronic component 410. The electronic component 10 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). The gate electrode assemblies 416, 418 are provided on the surface 414 of the substrate 412.

The gate electrode assembly 416 has the two gate electrodes 420, 422 in this case as well. The individual gate electrodes 420, 422 are electrically isolated from one another in a suitable manner with insulating layers 424. The gate electrode assemblies 416, 418 are provided in layers, wherein the insulating layer 424 is provided between each gate electrode 420, 422. The gate electrodes 420, 422 further comprise electrode fingers 426, 428, which are arranged parallel to another on the surface 414 of the substrate 412.

The gate electrode assemblies 416, 418 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 420, 422 of the gate electrode assembly 416, a potential well 430 is generated in the substrate 412. A quantum dot or charge carrier trapped in this potential well 430 can thus be transported through the substrate in this manner. The potential well 430 is transported longitudinally through the substrate through suitable control of the electrode fingers 426, 428 with sinusoidal voltages. The quantum dot or charge carrier confined in such a potential well 430 can be transported with this potential well 430 over a greater distance in the two-dimensional electron gas of the substrate 412 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 418, on the other hand, forms a static double potential well 434. The gate electrode assembly 418 comprises for this purpose the barrier gate electrodes 436, 438, 440 and two pump gate electrodes 442, 444, which can set a quantum dot 432, 448, 450, 454 or a charge carrier in motion or in oscillation. The pump gate electrodes 442, 444 are alternately arranged between the barrier gate electrodes 436, 438, 440. The gate electrodes 436, 438, 440, 442, 444 of the gate electrode assembly 418 are also separated from one another by an insulating layer 424. Each of the gate electrodes 436, 438, 440, 442, 444 has electrode fingers 437, 439, 441, 443, 445. The electrode fingers 437, 439, 441, 443, 445 can be seen in this sectional drawing.

In this figure, the sequences in the substrate 412 of the electronic component 410 for initializing a quantum state of a qubit in a quantum dot are shown schematically below the gate electrode assemblies 416, 418. The sequences from A to D of the positions of the potential wells 430, 434 in the substrate 412 are shown below this to explain the function. The electrode fingers 426, 428 of the gate electrode assembly 416 form the movable potential well 430 through the substrate 412. The movement of the potential well 430 is effected by appropriately interconnecting the electrode fingers 426, 428. The electrode fingers 426, 428 of the gate electrode assembly 416 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential well 442 through the substrate 412.

By means of the gate electrodes 436, 438, 440 and 442, 444, the static double potential well 434 is generated on the one hand, and on the other hand, the movable potential well 430 is generated with the gate electrodes 420, 422. Two charge carriers 448 from the reservoir 449 are introduced into the first potential well 446 of the static double potential well 434. The charge carriers 448 are split and oriented with a stimulator 451 comprising the pump gate electrodes 442, 444, for example with the aid of a gradient magnetic field. The split quantum dot charge carrier 450 tunnels quantum mechanically into the second static potential well 452 of the double potential well 434, which is indicated by the arrow 453. Only the quantum dot charge carrier 454 remains in the first static potential well 446. The quantum states of the quantum dots 450, 454 in the potential wells 446, 452 are known due to the orientation of an applied gradient magnetic field.

The movable potential well 430 is now moved towards the second static potential well 452 of the static double potential well 434.

Via tunneling, arrow 453, the charge carrier 450 moves from the static potential well 452 into the movable potential well 430. The quantum dot 450 can now be guided away with the movable potential well 430, arrow 458. The quantum mechanical state of the quantum dot 450 is known, as a result of which a qubit can be initialized, for example.

FIG. 16 shows a further exemplary embodiment of an electronic component 410, which is again formed from a semiconductor heterostructure. The structures of the component are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 412 for the electronic component 410. The electronic component 410 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). The gate electrode assemblies 416, 418 are provided on the surface 414 of the substrate 412.

The gate electrode assembly 416 has two gate electrodes 420, 422. The individual gate electrodes 420, 422 are electrically isolated from one another in a suitable manner with insulating layers 424. The gate electrodes 420, 422 of the gate electrode assembly 416 are provided for this purpose in layers, wherein the insulating layer 424 is provided between each gate electrode 420, 422 of the gate electrode assembly 416. The gate electrodes 420, 422 further comprise the electrode fingers 426, 428, which are arranged parallel to another on the surface 414 of the substrate 412.

The gate electrode assemblies 416, 418 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 420, 422 of the gate electrode assembly 416, a movable potential well is generated in the substrate 412. A quantum dot 442 or charge carrier trapped in this potential well can thus be transported through the substrate in this manner. The potential well is transported longitudinally through the substrate through suitable control of the electrode fingers 426, 428 with sinusoidal voltages. The quantum dot 442 confined in such a potential well can be transported with this potential well over a greater distance in the two-dimensional electron gas of the substrate 412 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 418 forms a static potential well. The gate electrode assembly 418 comprises for this purpose the barrier gate electrodes 436, 440 and the pump gate electrode 442, which can set a quantum dot or a charge carrier in motion or in oscillation. The pump gate electrode 442 is arranged between the barrier gate electrodes 436 and 440. Each of the gate electrodes 436, 440, 442 has electrode fingers 437, 441, 443.

The barrier gate electrode assembly 418 is adjacent to the reservoir 449 for effecting changes in charge.

FIG. 17 shows a section of a further exemplary embodiment of the electronic component 410, which is formed from a semiconductor heterostructure. The structures of the component 410 are preferably nanoscale structures. Undoped silicon germanium (SiGe) is used as the substrate 412 for the electronic component 410. The electronic component 410 is designed in such a manner that it comprises a two-dimensional electron gas (2DEG). The gate electrode assemblies 416, 418 are provided on the surface 414 of the substrate 412.

The gate electrode assembly 416 has the two gate electrodes 420, 422 in this case as well. The individual gate electrodes 420, 422 are electrically isolated from one another in a suitable manner with insulating layers 424. The gate electrode assemblies 416, 418 are provided in layers, wherein the insulating layer 424 is provided between each gate electrode 420, 422. The gate electrodes 420, 422 further comprise electrode fingers 426, 428, which are arranged parallel to another on the surface 414 of the substrate 412.

The gate electrode assemblies 416, 418 are supplied with a suitable voltage via electrical connections. By suitably applying sinusoidal voltages to the gate electrodes 420, 422 of the gate electrode assembly 416, a potential well 430 is generated in the substrate 412. A quantum dot or charge carrier trapped in this potential well 430 can thus be transported through the substrate in this manner. The potential well 430 is transported longitudinally through the substrate through suitable control of the electrode fingers 426, 428 with sinusoidal voltages. The quantum dot or charge carrier confined in such a potential well 430 can be transported with this potential well 430 over a greater distance in the two-dimensional electron gas of the substrate 412 made of SiGe without experiencing a quantum mechanical change of state.

The gate electrode assembly 418, on the other hand, forms a static potential well 470. The gate electrode assembly 418 comprises for this purpose the barrier gate electrodes 436, 440 and a pump gate electrode 442, which can set a quantum dot 48 or a charge carrier in motion or in oscillation. The pump gate electrode 442 is arranged between the barrier gate electrodes 436, 440. The gate electrodes 436, 440, 442 of the gate electrode assembly 418 are also separated from one another by an insulating layer 424. Each of the gate electrodes 436, 440, 442 has electrode fingers 437, 441, 443. The electrode fingers 437, 441, 443 can be seen in this sectional drawing.

In this figure, the sequences in the substrate 412 of the electronic component 410 for initializing a quantum state of a qubit in a quantum dot are shown schematically below the gate electrode assemblies 416, 418. The sequences from A to D of the positions of the potential wells 430, 470 in the substrate 412 are shown below this to explain the function. The electrode fingers 426, 428 of the gate electrode assembly 416 form the movable potential well 430 through the substrate 412. The movement of the potential well 430 is effected by appropriately interconnecting the electrode fingers 426, 428. The electrode fingers 426, 428 of the gate electrode assembly 416 provided for this purpose are periodically and alternately interconnected, which effects an almost continuous movement of the potential well 442 through the substrate 412.

By means of the gate electrodes 436, 440, and 442, the static potential well 470 is generated on the one hand, and on the other hand, the movable potential well 430 is generated by means of the gate electrodes 420, 422. Two charge carriers 448 from the reservoir 449 are introduced into the potential well 470. The charge carriers 448 are split and oriented with the stimulator 451, for example with the aid of a gradient magnetic field. The split charge carrier 450 tunnels quantum mechanically into the movable potential well 430, which is indicated by the arrow 453. Only the charge carrier 454 remains in the static potential well 470. The quantum states of the quantum dots 450, 454 in the potential wells 470, 430 are known due to the orientation of an applied gradient magnetic field.

The quantum dot 450 can now be guided away with the movable potential well 430, arrow 458. The quantum mechanical state of the quantum dot 450 is known, as a result of which a qubit can be initialized, for example.

LIST OF REFERENCE SIGNS

• • 10 Structure component
  • 12 Substrate
  • 14 Surface
  • 16 Functional element (translation)
  • 18 Functional element (branch)
  • 20 Functional element (manipulation)
  • 22 Functional element (read-out)
  • 24 Functional element (initialization)
  • 26 Unit cell
  • 110 Electronic component
  • 112 Substrate
  • 114 Surface
  • 116 Gate electrode assembly
  • 118 Gate electrode assembly
  • 120 Gate electrode assembly
  • 122 Gate electrodes
  • 124 Gate electrodes
  • 126 Gate electrodes
  • 128 Gate electrodes
  • 130 Insulating layers
  • 132 Electrode fingers
  • 134 Electrode fingers
  • 136 Electrode fingers
  • 138 Electrode fingers
  • 140 Intersection area
  • 142 Barrier gate electrode
  • 144 Barrier gate electrode
  • 146 Pump gate electrode
  • 148 Barrier gate electrode
  • 150 Movable potential well
  • 152 Quantum dot
  • 154 Arrow
  • 210 Electronic component
  • 212 Substrate
  • 214 Surface
  • 216 Gate electrode assembly
  • 218 Gate electrode assembly
  • 220 Gate electrode
  • 222 Gate electrode
  • 224 Gate electrode
  • 226 Gate electrode
  • 227 Insulating layer
  • 228 Electrode fingers
  • 230 Electrode fingers
  • 232 Electrode fingers
  • 234 Electrode fingers
  • 236 Adjacent region
  • 238 Manipulation zone
  • 239 Manipulator
  • 240 Gate electrode assembly
  • 242 Barrier gate electrodes
  • 244 Barrier gate electrodes
  • 246 Barrier gate electrodes
  • 248 Pump gate electrodes
  • 250 Pump gate electrodes
  • 252 Quantum dot
  • 254 Quantum dot
  • 256 Movable potential well
  • 258 Movable potential well
  • 260 Static double well
  • 262 Horizontal arrows
  • 310 Electronic component
  • 312 Substrate
  • 314 Surface
  • 316 Gate electrode assembly
  • 318 Gate electrode assembly
  • 320 Gate electrodes
  • 322 Gate electrodes
  • 324 Insulating layer
  • 326 Electrode fingers
  • 328 Electrode fingers
  • 330 Barrier gate electrode
  • 332 Barrier gate electrode
  • 334 Pump gate electrode
  • 336 Sensor element
  • 338 Barrier gate electrodes
  • 340 Pump gate electrode
  • 342 Quantum dot
  • 344 Quantum dot
  • 346 Moved potential well
  • 348 Static potential well
  • 350 Arrow (transportation)
  • 352 Arrow (tunneling)
  • 358 Charge carrier
  • 360 Split quantum dot
  • 362 Double potential well
  • 364 First static potential well
  • 366 Second static potential well
  • 410 Electronic component
  • 412 Substrate
  • 414 Surface
  • 416 Gate electrode assembly
  • 418 Gate electrode assembly
  • 420 Gate electrode
  • 422 Gate electrode
  • 424 Insulating layers
  • 426 Electrode fingers
  • 428 Electrode fingers
  • 430 Potential well
  • 432 Quantum dot
  • 434 Static double potential well
  • 436 Barrier gate electrode
  • 437 Electrode fingers
  • 438 Barrier gate electrode
  • 439 Electrode fingers
  • 440 Barrier gate electrode
  • 441 Electrode fingers
  • 442 Pump gate electrode
  • 443 Electrode fingers
  • 444 Pump gate electrode
  • 445 Electrode fingers
  • 446 1st static potential well
  • 448 Charge carrier
  • 449 Reservoir
  • 450 Split quantum dot
  • 451 Stimulator
  • 452 2nd static potential well
  • 453 Arrow (tunneling)
  • 454 Remaining quantum dot
  • 458 Arrow (transportation)
  • 460 Arrow (exchange interaction)
  • 470 Potential well

Claims

1.-22. (canceled)

23. An electronic structure component (10, 110, 210, 310, 410) for logically connecting qubits of a quantum computer, which is formed by a semiconductor component or a semiconductor-like structure, comprising:

a substrate (12) with a two-dimensional electron gas or electron hole gas;

gate electrode assemblies (116, 118, 120) having gate electrodes (122, 124, 126, 128), which are arranged on a surface (14) of the electronic structure component (10, 110, 210, 310, 410);

electrical contacts for connecting the gate electrode assemblies (116, 118, 120) to voltage sources; and

parallel electrode fingers (132, 134, 136, 138) being part of the gate electrodes (122, 124, 126, 128) of the gate electrode assemblies (116, 118, 120),

wherein logical connections of functional components (16, 18, 20, 22, 24) have gate electrode assemblies (116, 118, 120) for generating static (260, 364, 366) and/or moving potential wells (256, 258) and/or potential barriers (142, 144) for processing quantum dots (152, 342, 344) in the substrate (12).

24. The electronic structure component according to claim 23,

further comprising a functional element (16) for moving a quantum dot (152, 342, 344) in the substrate (12).

25. The electronic structure component according to claim 24,

wherein the electrode fingers (132, 134, 136, 138) are interconnected in an periodically alternating manner, which effects an almost continuous movement of the potential well (256, 258) through the substrate (12), whereby a quantum dot (152, 342, 344) is transported with this potential well (256, 258).

26. The electronic structure component according to claim 25,

further comprising a functional element (18) for branching the movement of a quantum dot (152, 342, 344).

27. The electronic structure component according to claim 26,

wherein the functional element (18) comprises

a first and a second branching gate electrode assembly (116, 118) with gate electrodes in different direction,

wherein the electrode fingers (132, 134) of the gate electrodes (122, 124) are interconnected in a periodically alternating manner, which effects an almost continuous movement of the potential well (150) through the substrate (12), whereby a quantum dot (152) is transported in one direction with the potential well (150) of the first gate electrode assembly (116), and the quantum dot (152) can be moved in a different direction of travel with the potential well (150) in the second branching gate electrode assembly (118).

28. The electronic structure component according to claim 27,

further comprising a third gate electrode assembly (120) for generating a switchable potential barrier arrangement (142, 144) in a region of the branch (140), which is switched for the branching of the quantum dot (152).

29. The electronic structure component according to claim 23,

further comprising a functional element (20) for manipulating qubits in quantum dots (252, 254).

30. The electronic structure component according to claim 29,

wherein the functional element (20) comprises a manipulator (239) that sets the qubit of the quantum dot to a definable quantum state in a manipulation zone (238),

wherein the manipulation zone (238) is provided in an adjacent region (236) formed by the first and second gate electrode assemblies (216, 240).

31. The electronic structure component according to claim 29,

further comprising means for a switchable magnetic field for splitting the electronic states with respect to their quantum mechanical states in the quantum dots (252, 254).

32. The electronic structure component according to claim 30,

wherein the manipulator (239) comprises means for generating an oscillating magnetic field and/or a gradient magnetic field in the manipulation zone (238).

33. The electronic structure component according to claim 30,

wherein the manipulator (239) comprises a microwave generator, which radiates microwaves into the manipulation zone (238) to manipulate the quantum state of the quantum dot (252, 254).

34. The electronic structure component according to claim 23,

further comprising a functional element (22) for reading out the quantum mechanical state of a qubit in a quantum dot (342).

35. The electronic structure component according to claim 34,

wherein the gate electrodes (320, 322) of the gate electrode assemblies (316, 318) have parallel electrode fingers (26, 28), whereby in a first gate electrode assembly (316), the electrode fingers (326, 328) are interconnected in a periodically alternating manner, which effects an almost continuous movement of the potential well (346) through the substrate (312), whereby a first quantum dot (342) is transported together with this potential well (346), and the electrode fingers of a second gate electrode assembly (318) form a static potential well (348, 362) in which a second charge carrier (358) with a known quantum mechanical state is provided, and

wherein a sensor element (336) is provided for detecting changes in the charge, which detects the charge in the static potential well (348, 362), whereby the first quantum dot (342) is transported to the second quantum dot (344).

36. The electronic structure component according to claim 35,

further comprising a magnetic field generator for generating a gradient magnetic field in order to initialize the quantum mechanical state of the quantum dot of the static potential well (348, 362).

37. The electronic structure component according to 34,

wherein the second gate electrode assembly (318) comprises two further gate electrodes (338, 340), which together form a static double potential well (362),

wherein each of the static potential wells (364, 366) has a quantum dot (344, 360) with different quantum mechanical states.

38. The electronic structure component according to claim 23,

further comprising a functional element (24) for initializing the quantum mechanical state of a quantum dot.

39. The electronic structure component according to claim 36,

further comprising a functional element (24) for initializing the quantum mechanical state of a quantum dot, comprising:

a reservoir (449), which is provided as a donor of charge carriers (448), wherein the gate electrodes (420, 422, 436, 438, 440, 442, 444) of the gate electrode assemblies (416, 418) have parallel electrode fingers (426, 428, 437, 439, 441, 443, 445); wherein the gate electrodes (436, 438, 440, 442, 444) of a first gate electrode assembly (418) in the substrate (412) form a static double potential well (434), or the gate electrodes (436, 440, 442) of a first gate electrode assembly (418) in the substrate (412) form a static potential well (470), in which charge carriers (448) are introduced from the reservoir (449) into the quantum dots (450, 454), wherein the gate electrodes (420, 422) of a second gate electrode assembly (416) form a movable potential well (430) in the substrate (412), wherein a charge carrier (450) with its quantum mechanical state can be transported with this potential well (430);

means for transferring two charge carriers (448) from the reservoir (449) into the static potential well (434, 446, 470);

a stimulator (451) for orienting or splitting the quantum dots (448, 450, 454); and

means for transferring a charge carrier from the static potential well (434, 452, 470) into the movable potential well (430).

40. The electronic structure component according to claim 39,

wherein the stimulator (451) is designed as a magnet, which generates a gradient magnetic field for initializing the quantum mechanical states in the two quantum dots (432, 450, 454) in the potential well (434, 470).

41. The electronic structure component according to claim 23,

wherein the substrate (12) of said electronic component comprises gallium arsenide (GaAs) and/or silicon germanium (SiGe).

42. The electronic structure component according to claim 23,

wherein the respectively interconnected gate electrodes (256, 258) for the moved potential well are configured such that a periodic and/or phase-shifted voltage can be applied to them.

43. The electronic structure component according to claim 23,

wherein every third electrode finger (132, 134, 136, 138) is connected to a gate electrode (122, 124, 126, 128) for the movable potential well.

44. The structure electronic component according to claim 23,

further comprising means of connection for connecting to a qubit of a quantum computer.