859 results about "Qubit" patented technology

The technology relates to enhancing performance of quantum sensor operation in a noisy environment. Quantum neural networks are used to pre- and post-process analog signals to which qubits of a quantum sensor are exposed. Intra-processing using additional quantum neural networks may also be employed. This approach filters out noise from both the input analog signal and the system itself to achieve a very high signal to noise ratio. This permits the system to detect induced dynamics associated during exposure of the qubits to the analog signals. This enables the quantum sensor to sense a change in a state of a system under test, which can be beneficial for areas such as imaging, magnetometry, sensing electric fields, optomechanical sensors, quantum radar and other areas where enhanced signal to noise ratios are desired.

In a general aspect, a quantum program can be automatically synthesized or compiled. In some implementations, a discretized state space is obtained. The discretized state space includes a plurality of states for one or more qubits of a quantum processor. A discrete action space is obtained. The discrete action space includes a plurality of unitary operations for the one or more qubits of the quantum processor. A policy that uses the discretized state space and the discrete action space to generate quantum programs for quantum state preparation is defined. A dynamic programming process is used to improve the policy. An initial state and a target state of the one or more qubits is identified. The policy is used to generate a quantum program to produce the target state from the initial state. The quantum program include a subset of the unitary operations in the discrete action space.

One or more systems, devices, methods of use and / or methods of fabrication provided herein relate to a device that can facilitate qubit measurement with isolation imposed between a quantum processor and a respective qubit measurement circuit and / or which respective qubit measurement circuit can have a small footprint, such as within a respective cryogenic chamber of a quantum system. According to one embodiment, a device comprises an isolator circuit having a bandpass filter configuration coupled between a pair of ports and the bandpass filter configuration comprising two or more poles. Two or more shunt resonators can be realized as the two or more poles, wherein the two or more shunt resonators can comprise DC SQUIDs and can be coupled together with one or more admittance inverters. A non-reciprocal signal transmission can be generated between the two ports by RF pumping the DC SQUIDs.

The invention discloses a quantum bit mapping optimization method for hardware guidance and fidelity perception and a related device, and belongs to the field of quantum computing, and the method comprises the steps: defining each node in a hardware coupling graph of a target quantum processor as an initial community; evaluating all adjacent community pairs according to a reward function defined based on modularity and fidelity of candidate communities, selecting an optimal community pair for fusion, and taking the community with the largest current scale as an optimal candidate area; iteratively executing a community fusion step until a converged single community is obtained; and selecting an optimal candidate region with the physical quantum bit number greater than or equal to the logic quantum bit number of the quantum circuit to be mapped and the minimum scale, and outputting a mapping sub-graph. According to the method, through a recursive community fusion strategy, the operation range of the solver is restrained in a subspace with the scale greatly reduced and the quality better, the problem of combinatorial explosion caused by global search is fundamentally avoided, and the calculation overhead is greatly reduced.

The invention relates to the technical field of quantum computing, and provides a linear complexity quantum state preparation method based on tensor decomposition and a quantum circuit construction system.The high-dimensional tensor is decomposed into a series of low-rank core tensors through continuous singular value decomposition, each core tensor in a core tensor sequence is expanded into a unitary matrix, and the unitary matrix is used as a quantum circuit; the unitary matrix sequence is mapped to quantum lines coupled using adjacent qubits, and the quantum lines are run to prepare a target quantum state. Based on this, the line generated by the method can approximately or accurately prepare a target quantum state only by coupling adjacent quantum bits, and is perfectly adaptive to quantum chips of linear or grid topologies such as superconducting and semiconductor quantum dots and the like.

A quantum computer system comprises first and second registers which are used to separate a quantum state into multiple subspaces of a 2n dimensional Hilbert space. A quantum state comprising 2n elements is defined on the first register, the first register comprising n qubits; a quantum state is defined on the second register, the second register comprising one or more qubits; and receiving a value k, where k is a binary integer such that 0 =< k =< n. The method further performing a bit-wise iteration process comprising: (i) performing a quantum entanglement between the registers to separate the quantum state on the first register into distinct subspaces of the Hilbert space which are indexed by the entangled values on the second register, and (ii) measuring an outcome on the second register to find a match with a portion of k, wherein said portion of k increases incrementally with the iteration process until the match is with all of k. The bit-wise iteration is used to separate the quantum state on the first register into subspaces of the Hilbert space, wherein elements of the subspaces have different Hamming weights, and one subspace contains only elements of Hamming weight k.

Quantum computers with a limited number of input qubits are used to perform machine learning processes having a far greater number of trainable features. A list of features of a field are divided into a plurality of feature groups. Each of the feature groups includes a respective group of some, but not all, of the features. A first machine learning process is performed to train a first instance of a quantum computer model, where the feature groups are used as inputs. Based on the first machine learning process being performed, a subset of the feature groups is selected for a second machine learning process. Thereafter, the second machine learning process is performed to train one or more second instances of the quantum computer model. The individual features of the selected subset of the feature groups are used as inputs for the second instances of the quantum computer model.

A quantum isolation zone (QIZ) controller executing on a quantum computing system, makes a determination to initiate, for a first QIZ of a plurality of different QIZs, a first local service instance of a global service instance that is executing on the quantum computing system, the first QIZ having a first set of qubits associated therewith. The first local service instance is caused to be initiated, and the QIZ controller modifies a local service data structure to indicate that the first local service instance is associated with the first QIZ.

An information processing apparatus causes a quantum computer to perform a first gate operation in accordance with an ancilla state generation circuit representing a procedure of generating a code including a logical qubit representing an ancilla state and a gauge qubit representing a redundant degree of freedom other than the ancilla state. Next, the information processing apparatus causes the quantum computer to perform a second gate operation in accordance with an error detection circuit representing a procedure of detecting an error occurring in a plurality of physical qubits constituting the code generated by the first gate operation. Then, the information processing apparatus determines the presence or absence of the error on the basis of a measurement value obtained by the second gate operation, the measurement value indicating the state of the gauge qubit.

The invention discloses a quantum circuit conversion method and system, electronic equipment and a storage medium, and relates to the technical field of quantum circuit conversion, and the method comprises the steps: extracting a feature vector of a logic quantum circuit based on initial quantum bit mapping; the feature vector is input into a pre-trained decision tree, recommendation parameters of a line conversion algorithm are obtained, the decision tree is constructed by a training set, and the feature vector of each sample corresponds to the optimal parameter of the decision tree, namely the parameter with the minimum number of physical line gates; and configuring a line conversion algorithm by using recommended parameters, converting a logic line into a physical line, and ensuring that all two quantum bit gates meet quantum computer connected graph constraints and are equivalent in function. According to the method, adaptive parameter configuration can be achieved through the feature vectors and the decision tree, the line conversion quality is effectively improved, the number of physical line gates is remarkably reduced, and the quantum program execution efficiency is improved on the premise that function equivalence and connectivity are guaranteed.

Methods, systems, and apparatus for verified quantum phase estimation. In one aspect, a method includes repeatedly performing a experiment. Performing one repetition of the experiment includes: applying a second unitary to a system register of N qubits prepared in a target computational basis state; applying, conditioned on a state of a control qubit, a first unitary to the system register; applying an inverse of the second unitary to the system register and measuring each qubit to determine an output state of the system register; measuring the control qubit to obtain a corresponding measurement result m; and post-selecting on the target computational basis state by, in response to determining that the output state indicates that each qubit was in the target computational basis state prior to measurement, incrementing a first or second classical variable by (−1)m. Phases or expectation values of the first unitary are estimated based on the classical variables.

Systems, methods, and computer-readable media of implementing a qubit gate for non-classical computing include implementing a qubit gate on a qubit of an array of qubits, wherein qubit states of said qubit are within a metastable manifold, wherein said qubit states are nuclear spin states, and wherein said qubit gate comprises a multi-photon transition through an intermediate metastable state.

Aspects of the disclosure include a technique for quantum lookup. Aspects include, in response to receiving an input, routing the input through first quantum routers to determine a first output. Aspects include routing the first output to at least one second quantum router, the at least one second quantum router feeding the first output to a gate tree, the gate tree generating a second output that is fed to qubits, the qubits performing operations generating readouts. Aspects include routing the readouts through third quantum routers, the third quantum routers arranged to output the readouts.

An electronic device includes a quantum processor including a plurality of qubits. The quantum processor runs a plurality of instances of a quantum program using a separate set of qubits from among the qubits for each instance of the quantum program. The quantum processor then sets quantum states for ancilla qubits from among the qubits based on quantum states of respective groups of associated qubits from the separate sets of qubits. The quantum processor next provides an output of the instances of the quantum program based on the quantum states of the ancilla qubits.

A quantum processor is discussed. the quantum processor having a flux compensation circuit communicatively coupled to a first qubit. The flux compensation circuit includes a quantum flux parametron (QFP) flux pump circuit with a first QFP in communication with the first qubit and a storage circuit with a second Josephson junction and a storage loop coupled in series with the QFP flux pump circuit. The communication between the QFP flux pump circuit and the storage loop is mediated by the second Josephson junction. A first control line is in communication with the first Josephson junction and a second control line is in communication with the second Josephson junction. In use. flux stored in the storage loop back acts on the first qubit.

Methods and systems for mitigating the effects of defects in a quantum processor are provided. A mitigation system includes a quantum processor comprising a plurality of qubits. The system includes a light emitting source that can be tuned to produce light pulses of different wavelengths. The system includes an array of bandpass filters. Each bandpass filter is aligned with a qubit on the quantum processor and has a unique pass band. The system may include a controller configured to receive a selection of a qubit and to tune the light emitting source to emit a light pulse having a wavelength that falls within a range of a bandpass filter that is aligned with the selected qubit. The light pulse is used to scramble an ensemble of strongly coupled two-level system (TLS) in the processor.

A method of method of classifying data is disclosed. The method comprises manipulating quantum states of qubits of a quantum computing device based on a first copy of a test vector, a second copy of the test vector, a first training vector and a second training vector, so as to load a modified first copy of the test vector, a modified second copy of the test vector, a modified first training vector and a modified second training vector onto the quantum computing device, wherein the magnitude of the angle between the modified first copy of the test vector and the modified first training vector is equal to the magnitude of the angle between the first copy of the test vector and the first training vector, and where the magnitude of the angle between the modified second copy of the test vector and the modified second training vector is equal to the magnitude of the angle between the second copy of the test vector and the second training vector. The method also comprises performing quantum interference between the modified first copy of the test vector and the modified second copy of the test vector, and the modified first training vector and the modified second training vector, to provide modified quantum states of the qubits, performing a measurement on one or more of the qubits, and classifying the test vector based on the measurement.

Methods, systems, and apparatus for microwave pulse distortion compensation using reflection parameters from error amplification pulse sequences. In one aspect, a method includes generating a pre-distorted control signal that implements a single qubit rotation operation and applying the pre-distorted control signal to a qubit to perform the rotation operation on the qubit. The pre-distorted control signal comprises an inverted transfer function, where the inverted transfer function comprises values of parameters obtained through fitting measured qubit parasitic rotation angles per gate to a reflection model that models pulse distortion in the quantum computing device; and the qubit parasitic rotation angles per gate are measured using a first pulse sequence that amplifies out-of-phase pulse distortion in the quantum computing device and a second pulse sequence that amplifies in-phase pulse distortion in the quantum computing device.

A system for data content feature extraction and evaluation using a hybrid quantum and classical neural network is disclosed. The system receives an input vector that represents digital content and generates a first quantum state vector for the input vector. The system generates a second quantum state vector by performing a quantum convolution operation on the first quantum state vector. The system initiates a second feature vector by mapping each quantum bit within the second quantum state vector to a respective numerical value. The system generates an output feature vector by performing a convolution operation on the second feature vector. The system evaluates the output feature vector by comparing the output feature vector with an expected vector. The system determines that the output feature vector corresponds to the expected vector. In response, the system determines that the output feature vector represents the digital content.

A superconducting quantum circuit apparatus includes a qubit; and a first wiring with a wiring used as a transmission of a signal to generate a magnetic flux to be applied to the qubit and a wiring used as a transmission of a signal input by capacitive coupling to and / or output, by capacitive coupling from the qubit, combined together thereinto, as a single wiring.

A method of generating an entangled state for quantum computing includes providing respective qubit from a plurality of Bell pairs to a plurality of probabilistic entangling gates according to a predefined graph structure. The success probability for generating respective qubits of the entangled state using the probabilistic entangling gates is greater than a percolation threshold for the predefined graph structure.

The present invention relates to a quantum computer comprising NV centers in diamond as quantum bits, nuclear spins of nuclei strongly coupled to the NV centers, strongly constrained by these NV centers, as nuclear quantum bits (hereinafter referred to as strong nuclear quantum bits), and nuclear spins, weakly constrained by these NV centers, of nuclei weakly coupled to the NV centers as nuclear qubits (hereinafter referred to as weak nuclear qubits). The resonance energy for coupling the weakly coupled nuclear spins of the nuclei weakly coupled to the respective NV centers depends only weakly on the respective spin state of the electron configuration of the NV centers weakly coupled to that nuclear spin. The control mode of the quantum computer on nuclear spin under weak constraint of the NV center is different from the control mode of the quantum computer on nuclear spin under strong constraint of the NV center. To this end, the quantum computer preferably has a kernel qubit database that stores information about whether the kernel qubits are strongly coupled or weakly coupled.

Aspects of the present disclosure relate generally to systems and methods for detecting change in images using a quantum information processing (QIP) system. The method includes implementing a quantum circuit in the QIP system, the quantum circuit comprising at least an ancilla qubit denoted as |a> and qubits denoted as image qubit conditions on a |0> state and a |1> state of the ancilla qubit |a>. The method also includes loading a reference image and a test image onto image qubits controlled on the |0> state and the |1> state of the ancilla qubit |a> in the quantum circuit. The method further includes determining a state of the image qubits after measuring |1> on the ancilla qubit for a predetermined number of times, wherein the reference image is detected to be different from the test image when the state of the ancilla qubit measures |1>.

Provided is a quantum computing method for obtaining an optimal solution of a problem with multiple discrete variables, wherein the problem is represented by a cost function, the method comprising:—generating a graph structure from the cost function,—dividing the graph structure into at least two disjunct subgraph structures, wherein each subgraph structure comprises a subset of the multiple variables,—mapping each subgraph structure to a local cost function represented as local cost Hamiltonian,—determining, for each local cost Hamiltonian, all eigenstates corresponding to an energy below a predetermined cut off energy using a quantum processing device, wherein each variable of the subset of multiple variables is represented by a qubit of the quantum processing device,—recombining the determined eigenstates, and-approximating a ground state from the recombined eigenstates, wherein the ground state represents the optimal solution.

Aspects of the present disclosure relate generally to systems and methods for optimizing an implementation of a quantum chemistry task in a quantum circuit. The method includes obtaining a chemistry task presented as a Hamilton to implement in a Variational Quantum Eigensolver (VQE) circuit. The method also includes mapping the chemistry task to a qubit space of the VQE circuit with Unitary Coupled Cluster with Single and Double excitations (UCCSD) ansatz. The method also includes decomposing the fermionic excitations to Givens rotations and controlled-Z (CZ) gates by passing exponentiated Pauli forms in the VQE circuit to a cloud compiler. The method further includes after commuting the CZ gates through Givens rotations, cancelling the commuted CZ gates. The method further includes dropping CZ gates at the beginning and the end of the quantum circuit.

Systems and methods are described for quantum information retrieval. An example system may include a quantum cloning unit, a photon number splitting (PNS) unit, and a variable-strength measurement unit to enhance the accuracy and reliability of quantum state estimations without introducing substantial decoherence. The quantum cloning unit may be used to generate approximate clones of a qubit. If the information is encoded in a multi-photon state resulting in a multi-photon state qubit, then the photon number splitting (PNS) unit may be used to intercept the multi-photon state and reflect a single photon from the multi-photon state, which may then be subjected to quantum cloning. These qubits and qubit clones may then be subjected to variable-strength measurements, which provides detailed analysis with minor disturbance to quantum properties such as superposition and entanglement.

Please delete the Abstract of the Disclosure, and replace it with the following: A superconducting quantum circuit includes first to fourth qubits and a coupler including a loop circuit connected between one end and other end of the coupler and a capacitor connected in parallel to the loop circuit, wherein the loop circuit includes n (n>=2) first Josephson junctions arranged in series and a second Josephson junction arranged in parallel with the n first Josephson junctions with a junction size smaller than that of the first Josephson junction, the first and second qubits capacitively coupled to the one end of the coupler, the third and fourth qubits capacitively coupled to the other end of the coupler, a magnitude of a coupling coefficient of the four-body interaction by the coupler being configurable based on circuit parameters including at least the n and α (0<α<1) which is a ratio of a Josephson energy between the second Josephson junction and the first Josephson junction.

An approach for assisting in the generation of quantum source code. The approach may include receiving a quantum source code input with a specification of constraints of a quantum unit on which the quantum source code input is to be run, wherein the constraints include available quantum qubits or gates and / or available quantum parameters. The method creates a variation of the quantum source code input by analyzing the quantum source code input against trained models, wherein the variation includes adjustment of the quantum unit constraints depending on the specification of constraints the quantum unit. The method provides a recommendation based on the variation to assist in quantum source code generation.

The invention discloses a Hamiltonian determination architecture, method and device, electronic equipment and a storage medium, and relates to the technical field of quantum computing, the architecture comprises a superconducting quantum circuit composed of a plurality of superconducting quantum bits and a plurality of superconducting quantum interferometers, and a control device; every two superconducting quantum bits on the boundary of a two-dimensional array formed by a plurality of superconducting quantum bits are connected with a superconducting quantum interference device, every four superconducting quantum bits in the two-dimensional array are connected with a superconducting quantum interference device, and when the control device detects that the target Hamiltonian needs to be determined, the superconducting quantum interference device is connected with the superconducting quantum interference device. And adjusting the alternating current and / or the alternating voltage based on the target Hamiltonian, so that the superconducting quantum bit and the superconducting quantum interferometer are coupled to generate the target Hamiltonian. According to the method, the technical problem that more uncontrollable errors are introduced in the measurement process of the quantum surface code can be solved, the error correction efficiency of the quantum surface code is improved, and the superconducting quantum circuit is placed on a plane with an open boundary and is easy to prepare.