Abstract: A system and method for encoding a dataset in a quantum circuit for quantum machine learning in a system includes providing a dataset comprising a plurality of input features; for each input feature of the plurality of input features, applying the plurality of encoding quantum gates on one quantum bit (qubit) or a plurality of qubits, wherein each of the plurality of encoding quantum gates rotates the one qubit or the plurality of qubits by a rotation angle which is proportional to the input feature and one of a plurality of scaling factors, each of the plurality of encoding quantum gates is assigned a different one of the plurality of scaling factors, and the plurality of scaling factors comprises powers of two; applying the plurality of variational quantum gates; determining a plurality of measurement values for the qubit; adjusting the quantum circuit; and determining output data.

Abstract: A quantum key distribution device comprises an input signal path receiving a plurality of optical input signals from a transmitter device, an output signal path connected to the input signal path at a first end and emitting a plurality of first optical output signals at a second end, and a detector signal path connected to the input signal path at a third end and comprising a photon detector device at a fourth end opposite to the third end. The photon detector detects optical input signals from the transmitter device, and the quantum key distribution device establishes a shared quantum cryptographic key with the transmitter device based on the detected optical input signals. The input signal path forms an input path of a Mach-Zehnder interferometer, and the output signal path and the detector signal path form output paths of the Mach-Zehnder interferometer.

Abstract: A system and method for quantum key distribution includes determining an intrinsic loss along a quantum channel; generating a pulse sequence; transmitting the pulse sequence via the quantum channel; receiving the pulse sequence; determining invalid signal positions and providing the invalid signal positions; determining a first reconciled signal from the first signal and the invalid signal positions, and determining a second reconciled signal from the second signal and the invalid signal positions; determining a total loss along the quantum channel from the at least one test pulse received, determining a signal loss from the total loss and the intrinsic loss, and providing the signal loss; determining a shared by error correcting the first reconciled signal and the second reconciled signal; and determining an amplified key from the shared key by shortening the shared key by a shortening amount that is determined from the signal loss.

Abstract: The invention relates to a method for device-independent quantum key generation and distribution between a first and a second receiver, the method comprising the steps of: a) Generating an entangled information pair, comprising two entangled quantum moieties that have at least one quantum state entangled with each other, such as a polarization, b) Transmitting a first entangled quantum moiety of the two entangled quantum moieties to the first receiver (A) and a second entangled quantum moiety of the two entangled quantum moieties to the second receiver (B), and measuring the quantum states of the entangled moieties with a set of selected detection settings chosen randomly at each receiver c) In a modification step, assigning each measurement value b1 measured with a detection setting B1 a complementary value b 1 ? according to a noise-probability p, wherein the noise-probability p is larger than 0 and lower than 1, such that a modified plurality of measurement values b 1 ˜ is obtained

Abstract: A method for determining a quantum communication setup includes providing a component set indicative of a quantum communication setup comprising quantum communication components; selecting an action of a set of actions each indicative of a further quantum communication component; including the selected further quantum communication component in the component set; determining, from the component set, a quantum model; determining, from the component set and the quantum model, a maximum key rate by optimizing over an optimization parameter set comprising quantum communication component parameters; adjusting the reward value depending on the size of the maximum key rate in relation to a previous maximum key rate; and iteratively repeating the above steps until a termination criterion is satisfied, yielding an optimal component set and an optimal setup parameter set.

Abstract: A system and method for determining a secret cryptographic key shared between a sending unit and a receiving unit by using a communication channel comprising spatially separated amplifiers for secure long-distance communication includes transmitting a sequence of electromagnetic pulses via the communication channel through the amplifiers for establishing a shared secret cryptographic key, wherein each electromagnetic pulse corresponds to a bit of a random bit sequence according to a ciphering protocol, and at least one ciphering parameter is determined by maximizing the expected key generation rate using an information theory model, wherein a measured signal loss and at least one amplification parameter are taken into account as input parameters to the information theory model.

Abstract: A system and method for quantum key distribution includes determining an intrinsic loss along a quantum channel; generating a pulse sequence; transmitting the pulse sequence via the quantum channel; receiving the pulse sequence; determining invalid signal positions and providing the invalid signal positions; determining a first reconciled signal from the first signal and the invalid signal positions, and determining a second reconciled signal from the second signal and the invalid signal positions; determining a total loss along the quantum channel from the at least one test pulse received, determining a signal loss from the total loss and the intrinsic loss, and providing the signal loss; determining a shared by error correcting the first reconciled signal and the second reconciled signal; and determining an amplified key from the shared key by shortening the shared key by a shortening amount that is determined from the signal loss.