Systems, computer-implemented methods and/or computer program products are provided for facilitating error mitigation for classical data output from a classical system and/or for qubit data output from a quantum system. A system can comprise a memory that stores computer executable components and a processor that executes the computer executable components stored in the memory. The computer executable components can comprise a computation component that performs error mitigation employing less than a full set of assignment matrix elements. In one or more embodiments, the error mitigation can be performed without constructing an assignment matrix. Additionally and/or alternatively, the computer executable components can comprise a computation component that performs error mitigation employing an iterative solver using the less than a full set of assignment matrix elements as the initial input set for the iterative solver.

Techniques regarding calibrating one or more quantum decoder algorithms are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a memory that can store computer executable components. The system can also comprise a processor, operably coupled to the memory, and that can execute the computer executable components stored in the memory. The computer executable components can comprise a correlation inversion decoder component that can calibrate a quantum decoder algorithm for decoding a quantum error-correcting code by estimating hyperedge probabilities of a decoding hypergraph that are consistent with a syndrome dataset.

Embodiments of the present disclosure include systems and methods for reducing a sample complexity and a time complexity associated with noise-robust characterization of a quantum device. A plurality of copies of a Gibbs state of the quantum device in thermal equilibrium at a high-temperature. A plurality of estimates for expectation values of the plurality of copies of the Gibbs state. A plurality of cluster derivatives for a plurality of connected clusters of a low-degree Hamiltonian are calculated. A function is inverted on the plurality of estimates based on the plurality of cluster derivatives and a set of Hamiltonian coefficients are estimated for the low-degree Hamiltonian of the quantum device.

Aspects of the present disclosure may include a method and/or a system for identifying an ion chain having a plurality of trapped ions, selecting at least two non-consecutive trapped ions in the ion chain for implementing a qubit, applying at least a first Raman beam to shuttle at least one neighbor ion of the at least two non-consecutive trapped ions from a ground state to a metastable state, and applying at least a second Raman beam to one or more of the at least two non-consecutive trapped ions, after shuttling the at least one neighbor ion to the metastable state, to transition from a first manifold to a second manifold.

Method and apparatus for synchronizing and locking clocks identifies entangled pairs of photons by comparing a first and second list of measured state values of single photons, wherein the first list is compiled by photon arrival times measured using a first clock and the second list is compiled by photon arrival times measured using a second clock. Entangled pairs of photons are identified by a match of the measured state values of single photons in their respective lists. Elapsed times of the first and second clocks are determined by taking the difference between arrival times of respective identified entangled pairs of photons measured using their respective clocks. A rate of one of the first and second clocks is changed based on a difference between the elapsed times, thereby synchronizing the first and second clocks. Clocks are locked by repeating.

A method, apparatus and product includes obtaining a logical representation of a quantum circuit that is implementable by a plurality of alternative physical representations of the quantum circuit, each of which implementing the logical representation with a different error correction scheme and defining error correction schemes for the quantum circuit. The defining error correction schemes includes implementing a search algorithm on the alternative physical representations, wherein the search algorithm is configured to search for a physical representation of the quantum circuit with an assignment of a plurality of physical qubits to a plurality of logical qubits that is defined in view of a quality score. A quality metric used to compute the quality score is monotonically correlated to error rates of logical output qubits of the quantum circuit when implementing each alternative physical representation. The assignment is utilized to define the error correction schemes for the quantum circuit.

A method, apparatus and product includes obtaining a logical representation of a quantum circuit that is implementable by a plurality of alternative physical representations of the quantum circuit, each of which implementing the logical representation with a different error correction scheme and defining error correction schemes for the quantum circuit. The defining error correction schemes includes implementing a search algorithm on the alternative physical representations, wherein the search algorithm is configured to search for a physical representation of the quantum circuit with an assignment of a plurality of physical qubits to a plurality of logical qubits that is defined in view of a quality score. A quality metric used to compute the quality score is monotonically correlated to error rates of logical output qubits of the quantum circuit when implementing each alternative physical representation. The assignment is utilized to define the error correction schemes for the quantum circuit.

Techniques regarding error detection in one or more generated signals based on one or more signal-to-noise ratios are provided. For example, one or more embodiments described herein can include a system, which can include a memory that can store computer executable components. The system can also include a processor, operably coupled to the memory, and that can execute the computer executable components stored in the memory. The computer executable components can include a signal analysis component that can determine a signal-to-noise ratio associated with a generated signal, wherein the signal-to-noise ratio incorporates a signal value based on a reference signal and a noise value based on a difference between the reference signal and an acquired signal.

This application discloses a quantum gate optimization method performed by a computer device. The method includes: obtaining an initialized control external field corresponding to a quantum gate; applying the control external field to a quantum bit (qubit) corresponding to the quantum gate, and acquiring actual measurement data of the quantum gate, the actual measurement data being used for reflecting an actual characteristic of the quantum gate; calculating a gradient corresponding to the control external field based on the actual measurement data and ideal data, the ideal data being used for reflecting an ideal characteristic of the quantum gate; and updating the control external field according to the gradient to obtain an updated control external field, the updated control external field being applied to the qubit corresponding to the quantum gate to optimize precision of the quantum gate. The method is a closed-loop optimization solution driven and implemented by data feedback.

An entangled quantum cache includes a quantum store that receives a plurality of quantum states and is configured to store and order the plurality of quantum states and to provide select ones of the stored and ordered plurality of quantum states to a quantum data output at a first desired time. A fidelity system is configured to determine a fidelity of at least some of the plurality of quantum states. A classical store is coupled to the fidelity system and configured to store classical data comprising the determined fidelity information and an index that associates particular ones of classical data with particular ones of the plurality of quantum states and to supply at least some of the classical data to a classical data output at a second desired time. A processor is connected to the classical store and determines the first time based on the index.