Bell sampling from quantum circuits

Fuente: arXiv
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Main Authors: Hangleiter, Dominik, Gullans, Michael J.
Format: Preprint
Published: 2023
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author Hangleiter, Dominik
Gullans, Michael J.
author_facet Hangleiter, Dominik
Gullans, Michael J.
contents A central challenge in the verification of quantum computers is benchmarking their performance as a whole and demonstrating their computational capabilities. In this work, we find a universal model of quantum computation, Bell sampling, that can be used for both of those tasks and thus provides an ideal stepping stone towards fault-tolerance. In Bell sampling, we measure two copies of a state prepared by a quantum circuit in the transversal Bell basis. We show that the Bell samples are classically intractable to produce and at the same time constitute what we call a circuit shadow: from the Bell samples we can efficiently extract information about the quantum circuit preparing the state, as well as diagnose circuit errors. In addition to known properties that can be efficiently extracted from Bell samples, we give several new and efficient protocols: an estimator of state fidelity, a test for the depth of the circuit and an algorithm to estimate a lower bound to the number of T gates in the circuit. With some additional measurements, our algorithm learns a full description of states prepared by circuits with low T-count.
format Preprint
id arxiv_https___arxiv_org_abs_2306_00083
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Bell sampling from quantum circuits
Hangleiter, Dominik
Gullans, Michael J.
Quantum Physics
Quantum Gases
Computational Complexity
A central challenge in the verification of quantum computers is benchmarking their performance as a whole and demonstrating their computational capabilities. In this work, we find a universal model of quantum computation, Bell sampling, that can be used for both of those tasks and thus provides an ideal stepping stone towards fault-tolerance. In Bell sampling, we measure two copies of a state prepared by a quantum circuit in the transversal Bell basis. We show that the Bell samples are classically intractable to produce and at the same time constitute what we call a circuit shadow: from the Bell samples we can efficiently extract information about the quantum circuit preparing the state, as well as diagnose circuit errors. In addition to known properties that can be efficiently extracted from Bell samples, we give several new and efficient protocols: an estimator of state fidelity, a test for the depth of the circuit and an algorithm to estimate a lower bound to the number of T gates in the circuit. With some additional measurements, our algorithm learns a full description of states prepared by circuits with low T-count.
title Bell sampling from quantum circuits
topic Quantum Physics
Quantum Gases
Computational Complexity
url https://arxiv.org/abs/2306.00083