A Butterfly Effect in Encoding-Decoding Quantum Circuits

Fuente: arXiv
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Autori principali: Dallas, Emanuel, Andreadakis, Faidon, Zanardi, Paolo
Natura: Preprint
Pubblicazione: 2024
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author Dallas, Emanuel
Andreadakis, Faidon
Zanardi, Paolo
author_facet Dallas, Emanuel
Andreadakis, Faidon
Zanardi, Paolo
contents The study of information scrambling has profoundly deepened our understanding of many-body quantum systems. Much recent research has been devote to understanding the interplay between scrambling and decoherence in open systems. Continuing in this vein, we investigate scrambling in a noisy encoding-decoding circuit model. Specifically, we consider an $L$-qubit circuit consisting of a Haar-random unitary, followed by noise acting on a subset of qubits, and then by the inverse unitary. Scrambling is measured using the bipartite algebraic out-of-time-order correlator ($\mathcal{A}$-OTOC), which allows us to track information spread between extensively sized subsystems. We derive an analytic expression for the $\mathcal{A}$-OTOC that depends on system size and noise strength. In the thermodynamic limit, this system displays a \textit{butterfly effect} in which infinitesimal noise induces macroscopic information scrambling. We also perform numerical simulations while relaxing the condition of Haar-randomness, which preliminarily suggest that this effect may manifest in a larger set of circuits.
format Preprint
id arxiv_https___arxiv_org_abs_2409_16481
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Butterfly Effect in Encoding-Decoding Quantum Circuits
Dallas, Emanuel
Andreadakis, Faidon
Zanardi, Paolo
Quantum Physics
The study of information scrambling has profoundly deepened our understanding of many-body quantum systems. Much recent research has been devote to understanding the interplay between scrambling and decoherence in open systems. Continuing in this vein, we investigate scrambling in a noisy encoding-decoding circuit model. Specifically, we consider an $L$-qubit circuit consisting of a Haar-random unitary, followed by noise acting on a subset of qubits, and then by the inverse unitary. Scrambling is measured using the bipartite algebraic out-of-time-order correlator ($\mathcal{A}$-OTOC), which allows us to track information spread between extensively sized subsystems. We derive an analytic expression for the $\mathcal{A}$-OTOC that depends on system size and noise strength. In the thermodynamic limit, this system displays a \textit{butterfly effect} in which infinitesimal noise induces macroscopic information scrambling. We also perform numerical simulations while relaxing the condition of Haar-randomness, which preliminarily suggest that this effect may manifest in a larger set of circuits.
title A Butterfly Effect in Encoding-Decoding Quantum Circuits
topic Quantum Physics
url https://arxiv.org/abs/2409.16481