arXiv:2206.08410 · Entropy

Critical Quantum Metrology in the Non-Linear Quantum Rabi Model

Zu‐Jian Ying, Simone Felicetti, Gang Liu, Daniel Braak

Published Jul 22, 2022• 54 citations

Abstract

The quantum Rabi model (QRM) with linear coupling between light mode and qubit exhibits the analog of a second-order phase transition for vanishing mode frequency which allows for criticality-enhanced quantum metrology in a few-body system. We show that the QRM including a nonlinear coupling term exhibits much higher measurement precisions due to its first-order-like phase transition at finite frequency, avoiding the detrimental slowing-down effect close to the critical point of the linear QRM. When a bias term is added to the Hamiltonian, the system can be used as a fluxmeter or magnetometer if implemented in circuit QED platforms.

DOI: 10.3390/e24081015

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