Abstract: A method includes training a first QNN by sending a first dataset into the first QNN to generate a first output and configuring the first QNN into a first setting based on the training. The method also includes receiving a second dataset, using at least a portion of the first QNN to generate a second output using the first setting, and sending the second output to a second QNN, operatively coupled to the first QNN, to train the second QNN. The second QNN is configured in a fixed setting during training of the first QNN.

Abstract: The present disclosure relates to quantum computing methods and devices, wherein a computation corresponding to a certain desired unitary transformation of the Hilbert space of a quantum system, such as a set of qubits, is implemented by selective application of control pulses in order realize a continuous time quantum computation rather than by decomposing the unitary transformation into a sequence of gates taken from a fixed set of gates. In this way an effective Hamiltonian having an input matrix A encoded as an off-diagonal block connecting a first and a second subspace of the quantum system is then applied alternatingly with some standard Hamiltonian in order to obtain a time evolution corresponding to a given function f applied to the input matrix A.

Abstract: Systems and methods for performing open-loop quantum error mitigation using quantum measurement emulations are provided. The open-loop quantum error mitigation methods do not require the performance of state readouts or state tomography, reducing hardware requirements and increasing overall computation speed. To perform a quantum measurement emulation, an error mitigation apparatus is configured to stochastically apply a quantum gate to a qubit or set of qubits during a quantum computational process. The stochastic application of the quantum gate projects the quantum state of the affected qubits onto an axis, reducing a trace distance between the quantum state and a desired quantum state.

Abstract: Systems and methods for performing open-loop quantum error mitigation using quantum measurement emulations are provided. The open-loop quantum error mitigation methods do not require the performance of state readouts or state tomography, reducing hardware requirements and increasing overall computation speed. To perform a quantum measurement emulation, an error mitigation apparatus is configured to stochastically apply a quantum gate to a qubit or set of qubits during a quantum computational process. The stochastic application of the quantum gate projects the quantum state of the affected qubits onto an axis, reducing a trace distance between the quantum state and a desired quantum state.

Abstract: A method includes training a first QNN by sending a first dataset into the first QNN to generate a first output and configuring the first QNN into a first setting based on the training. The method also includes receiving a second dataset, using at least a portion of the first QNN to generate a second output using the first setting, and sending the second output to a second QNN, operatively coupled to the first QNN, to train the second QNN. The second QNN is configured in a fixed setting during training of the first QNN.

Abstract: A large-scale tunable-coupling ring array includes an input waveguide coupled to multiple ring resonators, each of which has a distinct resonant wavelength. The collective effect of these multiple ring resonators is to impart a distinct time delay to a distinct wavelength component (or frequency component) in an input signal, thereby carrying out quantum scrambling of the input signal. The scrambled signal is received by a receiver also using a large-scale tunable-coupling ring array. This receiver-end ring resonator array recovers the input signal by imparting a compensatory time delay to each wavelength component. Each ring resonator can be coupled to the input waveguide via a corresponding Mach Zehnder interferometer (MZI). The MZI includes a phase shifter on at least one of its arms to increase the tunability of the ring array.

Abstract: A large-scale tunable-coupling ring array includes an input waveguide coupled to multiple ring resonators, each of which has a distinct resonant wavelength. The collective effect of these multiple ring resonators is to impart a distinct time delay to a distinct wavelength component (or frequency component) in an input signal, thereby carrying out quantum scrambling of the input signal. The scrambled signal is received by a receiver also using a large-scale tunable-coupling ring array. This receiver-end ring resonator array recovers the input signal by imparting a compensatory time delay to each wavelength component. Each ring resonator can be coupled to the input waveguide via a corresponding Mach Zehnder interferometer (MZI). The MZI includes a phase shifter on at least one of its arms to increase the tunability of the ring array.

Abstract: A system and method for reducing coherent backscattering-induced errors in an optical gyroscope is provided. A first time-dependent phase modulation is applied to a first laser signal and a second phase modulation is applied to a second laser signal. The phase-modulated first laser signal propagates in a first direction through a waveguide coil and the phase-modulated second laser signal propagates in a second direction opposite the first direction through the waveguide coil. The first time-dependent phase modulation is applied to the phase-modulated second laser signal after the phase-modulated second laser signal propagates through the waveguide coil to produce a twice-phase-modulated second laser signal. The second time-dependent phase modulation is applied to the phase-modulated first laser signal after the phase-modulated first laser signal propagates through the waveguide coil to produce a twice-phase-modulated first laser signal.

Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical loop having a length and a laser source optically coupled to the loop. The laser source has a coherence length. Light from the source is transmitted to the loop as a first signal and a second signal counterpropagating along the loop. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after counterpropagating through the loop to generate a third signal. A ratio of the coherence length to the length of the loop is greater than 1.

Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical waveguide having a length and a laser source optically coupled to the waveguide. The laser source has a coherence length. Light from the source is transmitted to the waveguide as a first signal propagating along the waveguide in a first direction and a second signal propagating along the waveguide in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the waveguide to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.

Abstract: An optical sensor, a method of configuring an optical sensor, and a method of using an optical sensor are provided. The optical sensor includes an optical waveguide having a length and a laser source optically coupled to the waveguide. The laser source has a coherence length. Light from the source is transmitted to the waveguide as a first signal propagating along the waveguide in a first direction and a second signal propagating along the waveguide in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the waveguide to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.

Abstract: A fiber-optic sensor includes an optical fiber coil and a laser source optically coupled to the coil. Light from the source is transmitted to the coil as a first optical signal and a second optical signal counter-propagating through the coil. The optical paths of the first optical signal and the second optical signal are substantially reciprocal with one another and the first optical signal and the second optical signal are combined together after counter-propagating through the coil to generate a third optical signal. The laser source is frequency-modulated or can have a coherence length longer than a length of the coil.

Abstract: A fiber-optic sensor, a method of configuring a fiber-optic sensor, and a method of using a fiber-optic sensor are provided. The fiber-optic sensor includes an optical fiber coil having a length and a laser source optically coupled to the coil. The laser source has a coherence length. Light from the source is transmitted to the coil as a first signal propagating along the coil in a first direction and a second signal propagating along the coil in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the coil to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.

Abstract: In a database query operation, a quantum private query (QPQ) protocol allows a user to determine whether the database provider has been trying to obtain information about their query by performing quantum superpositions of different queries in addition to performing normal queries. This means that, in addition to being able to request the jth or the kth records in the database, the user can also request both records in a quantum superposition. To find out whether the database provider is trying to discover her queries, the user sends proper superpositions of queries and then checks the answer provided by the database to determine whether the superposition has been preserved. If superposition has not been preserved, the user can be confident that the database provider has cheated, and has tried to obtain information on the query.

Abstract: A fiber-optic sensor includes an optical fiber coil and a laser source optically coupled to the coil. Light from the source is transmitted to the coil as a first optical signal and a second optical signal counter-propagating through the coil. The optical paths of the first optical signal and the second optical signal are substantially reciprocal with one another and the first optical signal and the second optical signal are combined together after counter-propagating through the coil to generate a third optical signal. The laser source is frequency-modulated or can have a coherence length longer than a length of the coil.

Abstract: A fiber-optic sensor includes an optical fiber coil and a laser source optically coupled to the coil. Light from the source is transmitted to the coil as a first signal propagating along the coil in a first direction and a second signal propagating along the coil in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the coil to generate a third signal. The laser source is frequency-modulated or can have a coherence length longer than a length of the coil.

Abstract: A fiber-optic sensor, a method of configuring a fiber-optic sensor, and a method of using a fiber-optic sensor are provided. The fiber-optic sensor includes an optical fiber coil having a length and a laser source optically coupled to the coil. The laser source has a coherence length. Light from the source is transmitted to the coil as a first signal propagating along the coil in a first direction and a second signal propagating along the coil in a second direction opposite to the first direction. The optical paths of the first signal and the second signal are substantially reciprocal with one another and the first signal and the second signal are combined together after propagating through the coil to generate a third signal. The coherence length is greater than 1 meter or is in a range between 200 microns and 10 centimeters.

Abstract: In an address signal decoder for a RAM memory, address signals are decoded in a “bucket brigade” address decoding architecture in which the address signals or bits are sequentially sent along the same address decoding path. The inventive architecture comprises a set of node switches linked into a binary tree. The address signals enter at the root node of the binary tree. As each address signal reaches a node switch at the end the path, it sets the path direction for that switch node so that subsequent address signals that follow the path will use that path direction. The decoder can be used with classical or quantum RAM memories.

Abstract: In an address signal decoder for a RAM memory, address signals are decoded in a “bucket brigade” address decoding architecture in which the address signals or bits are sequentially sent along the same address decoding path. The inventive architecture comprises a set of node switches linked into a binary tree. The address signals enter at the root node of the binary tree. As each address signal reaches a node switch at the end the path, it sets the path direction for that switch node so that subsequent address signals that follow the path will use that path direction. The decoder can be used with classical or quantum RAM memories.

Abstract: In a database query operation, a quantum private query (QPQ) protocol allows a user to determine whether the database provider has been trying to obtain information about their query by performing quantum superpositions of different queries in addition to performing normal queries. This means that, in addition to being able to request the jth or the kth records in the database, the user can also request both records in a quantum superposition. To find out whether the database provider is trying to discover her queries, the user sends proper superpositions of queries and then checks the answer provided by the database to determine whether the superposition has been preserved. If superposition has not been preserved, the user can be confident that the database provider has cheated, and has tried to obtain information on the query.