Gate-Based Initialization and Fidelity in Correlated Open Quantum Systems

Fuente: arXiv
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Main Authors: Chen, Sirui, Chen, Jiahao, Davidović, Dragomir
Format: Preprint
Published: 2024
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author Chen, Sirui
Chen, Jiahao
Davidović, Dragomir
author_facet Chen, Sirui
Chen, Jiahao
Davidović, Dragomir
contents We present a minimal and general framework for initializing open quantum systems via gate operations, treating system-bath correlations and control dynamics on equal footing. Our protocol simulates thermal equilibration followed by a gate pulse, modeled using a time-dependent Bloch-Redfield equation accurate to second order in coherence. After the gate, the system exhibits hybrid dynamics: populations evolve Markovianly, while coherences dephase as if the system were initially factorized. In fast, strongly dephasing regimes, initial system-bath correlations can revive coherence. Gate fidelities reveal spin-echo-like suppression of errors near $2π$ rotations, indicating an intrinsic mechanism for error cancellation. The approach is efficient and broadly applicable to both quantum devices and molecular complexes. Applications include fidelity optimization with respect to bath correlation times and coherence tracking in systems such as the Fenna-Matthews-Olson complex. Our results show that long-lived excitonic coherences can arise from strongly non-Markovian dynamics triggered by ultrafast pulses.
format Preprint
id arxiv_https___arxiv_org_abs_2410_06292
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gate-Based Initialization and Fidelity in Correlated Open Quantum Systems
Chen, Sirui
Chen, Jiahao
Davidović, Dragomir
Quantum Physics
We present a minimal and general framework for initializing open quantum systems via gate operations, treating system-bath correlations and control dynamics on equal footing. Our protocol simulates thermal equilibration followed by a gate pulse, modeled using a time-dependent Bloch-Redfield equation accurate to second order in coherence. After the gate, the system exhibits hybrid dynamics: populations evolve Markovianly, while coherences dephase as if the system were initially factorized. In fast, strongly dephasing regimes, initial system-bath correlations can revive coherence. Gate fidelities reveal spin-echo-like suppression of errors near $2π$ rotations, indicating an intrinsic mechanism for error cancellation. The approach is efficient and broadly applicable to both quantum devices and molecular complexes. Applications include fidelity optimization with respect to bath correlation times and coherence tracking in systems such as the Fenna-Matthews-Olson complex. Our results show that long-lived excitonic coherences can arise from strongly non-Markovian dynamics triggered by ultrafast pulses.
title Gate-Based Initialization and Fidelity in Correlated Open Quantum Systems
topic Quantum Physics
url https://arxiv.org/abs/2410.06292