Exact analysis of AC sensors based on Floquet time crystals

Fuente: arXiv
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Main Authors: Tsypilnikov, Andrei, Fibger, Matheus, Iemini, Fernando
Format: Preprint
Published: 2025
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author Tsypilnikov, Andrei
Fibger, Matheus
Iemini, Fernando
author_facet Tsypilnikov, Andrei
Fibger, Matheus
Iemini, Fernando
contents We discuss the behavior of general Floquet time crystals (FTCs), including prethermal ones, in closed systems acting as AC sensors. We provide an analytical treatment of their quantum Fisher information (QFI) dynamics, which characterizes the ultimate sensor accuracy. By tuning the direction and frequency of the AC field, we show how to induce transitions resonantly between macroscopic paired cat states in the FTC sensor. This allows for robust Heisenberg scaling precision (QFI $\sim N^2 t^2$) for exponentially long times in the system size. The QFI dynamics exhibit, moreover, a characteristic step-like structure in time due to the eventual dephasing along the cat subspaces. The behavior is discussed for various initial sensor preparations, including ground states and low- and high-correlated states. Furthermore, we examine the performance of the sensor along the FTC phase transition, with the QFI capturing its critical exponents. Our findings are presented for both linear and nonlinear response regimes and illustrated for a specific FTC based on the long-range interacting LMG model.
format Preprint
id arxiv_https___arxiv_org_abs_2505_22731
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exact analysis of AC sensors based on Floquet time crystals
Tsypilnikov, Andrei
Fibger, Matheus
Iemini, Fernando
Quantum Physics
Other Condensed Matter
Statistical Mechanics
We discuss the behavior of general Floquet time crystals (FTCs), including prethermal ones, in closed systems acting as AC sensors. We provide an analytical treatment of their quantum Fisher information (QFI) dynamics, which characterizes the ultimate sensor accuracy. By tuning the direction and frequency of the AC field, we show how to induce transitions resonantly between macroscopic paired cat states in the FTC sensor. This allows for robust Heisenberg scaling precision (QFI $\sim N^2 t^2$) for exponentially long times in the system size. The QFI dynamics exhibit, moreover, a characteristic step-like structure in time due to the eventual dephasing along the cat subspaces. The behavior is discussed for various initial sensor preparations, including ground states and low- and high-correlated states. Furthermore, we examine the performance of the sensor along the FTC phase transition, with the QFI capturing its critical exponents. Our findings are presented for both linear and nonlinear response regimes and illustrated for a specific FTC based on the long-range interacting LMG model.
title Exact analysis of AC sensors based on Floquet time crystals
topic Quantum Physics
Other Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2505.22731