Boundary Time Crystals as AC sensors: enhancements and constraints

Fuente: arXiv
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Autori principali: Gribben, Dominic, Sanpera, Anna, Fazio, Rosario, Marino, Jamir, Iemini, Fernando
Natura: Preprint
Pubblicazione: 2024
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author Gribben, Dominic
Sanpera, Anna
Fazio, Rosario
Marino, Jamir
Iemini, Fernando
author_facet Gribben, Dominic
Sanpera, Anna
Fazio, Rosario
Marino, Jamir
Iemini, Fernando
contents We investigate the use of a boundary time crystals (BTCs) as quantum sensors of AC fields. Boundary time crystals are non-equilibrium phases of matter in contact to an environment, for which a macroscopic fraction of the many-body system breaks the time translation symmetry. We find an enhanced sensitivity of the BTC when its spins are resonant with the applied AC field, as quantified by the quantum Fisher information (QFI). The QFI dynamics in this regime is shown to be captured by a relatively simple ansatz consisting of an initial power-law growth and late-time exponential decay. We study the scaling of the ansatz parameters with resources (encoding time and number of spins) and identify a moderate quantum enhancement in the sensor performance through comparison with classical QFI bounds. Investigating the precise source of this performance, we find that despite of its long coherence time and multipartite correlations (advantageous properties for quantum metrology), the entropic cost of the BTC (which grows indefinitely in the thermodynamic limit) hinders an optimal decoding of the AC field information. This result has implications for future candidates of quantum sensors in open system and we hope it will encourage future study into the role of entropy in quantum metrology.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06273
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Boundary Time Crystals as AC sensors: enhancements and constraints
Gribben, Dominic
Sanpera, Anna
Fazio, Rosario
Marino, Jamir
Iemini, Fernando
Quantum Physics
Other Condensed Matter
Statistical Mechanics
We investigate the use of a boundary time crystals (BTCs) as quantum sensors of AC fields. Boundary time crystals are non-equilibrium phases of matter in contact to an environment, for which a macroscopic fraction of the many-body system breaks the time translation symmetry. We find an enhanced sensitivity of the BTC when its spins are resonant with the applied AC field, as quantified by the quantum Fisher information (QFI). The QFI dynamics in this regime is shown to be captured by a relatively simple ansatz consisting of an initial power-law growth and late-time exponential decay. We study the scaling of the ansatz parameters with resources (encoding time and number of spins) and identify a moderate quantum enhancement in the sensor performance through comparison with classical QFI bounds. Investigating the precise source of this performance, we find that despite of its long coherence time and multipartite correlations (advantageous properties for quantum metrology), the entropic cost of the BTC (which grows indefinitely in the thermodynamic limit) hinders an optimal decoding of the AC field information. This result has implications for future candidates of quantum sensors in open system and we hope it will encourage future study into the role of entropy in quantum metrology.
title Boundary Time Crystals as AC sensors: enhancements and constraints
topic Quantum Physics
Other Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2406.06273