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arXiv · 2305.15464

Quantum turnstiles for robust measurement of full counting statistics

Rhine Samajdar·Ewan McCulloch·Vedika Khemani·Romain Vasseur·Sarang Gopalakrishnan
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Abstract

We present a scalable protocol for measuring full counting statistics (FCS) in experiments or tensor-network simulations. In this method, an ancilla in the middle of the system acts as a turnstile, with its phase keeping track of the time-integrated particle flux. Unlike quantum gas microscopy, the turnstile protocol faithfully captures FCS starting from number-indefinite initial states or in the presence of noisy dynamics. In addition, by mapping the FCS onto a single-body observable, it allows for stable numerical calculations of FCS using approximate tensor-network methods. We demonstrate the wide-ranging utility of this approach by computing the FCS of the transferred magnetization in a Floquet Heisenberg spin chain, as studied in a recent experiment with superconducting qubits, as well as the FCS of charge transfer in random circuits.

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Rhine Samajdar, Ewan McCulloch, Vedika Khemani, Romain Vasseur, Sarang Gopalakrishnan. 2023-05-24. Quantum turnstiles for robust measurement of full counting statistics. https://doi.org/10.1103/physrevlett.133.240403

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