Quantum noise determination method and quantum state estimation method

Abstract

The embodiment of the invention provides a method for determining quantum circuit noise and a quantum state estimation method, and the method comprises the steps: carrying out N1 rounds of random measurement for a plurality of quantum units whose initial states are ground states, wherein each round of random measurement comprises the steps: inputting the plurality of quantum units into a pre-established random quantum circuit, measuring the plurality of quantum units evolved by the random quantum circuit, determining a first measurement result corresponding to the round of random measurement, and determining a random unitary matrix corresponding to the round of random measurement according to the state of the random quantum circuit; and determining noise parameters of the random quantum circuit based on N1 first measurement results corresponding to N1 rounds of random measurement and N1 random unitary matrixes. And determining a plurality of random samples of the to-be-measured state of the plurality of quantum units based on the noise parameter and N2 second measurement results and N2 random unitary matrixes obtained by random measurement of N2 rounds on the plurality of quantum units of the to-be-measured state.

Description

technical field

[0001] The invention relates to quantum computing, in particular to a method for determining quantum noise and estimating quantum states. Background technique

[0002] Quantum state property estimation refers to a general term for protocols that obtain required observations on unknown quantum states by specifying measurements. Common quantum state property estimation includes fidelity estimation, entanglement detection, Hamiltonian energy estimation, correlation function estimation and many other tasks. Estimation of quantum state properties plays an important role in various fields such as quantum chemistry, quantum simulation, quantum algorithm design, and many-body physics research. Specifically, in quantum chemistry, it is often necessary to effectively estimate the expected value of a given variable quantum state in the case of a specific Hamiltonian; when constructing a quantum computer and verifying quantum superiority, it is often necessary to test t...

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