Gaussian quantum metrology in a dissipative environment

TL;DR

This paper proposes a Gaussian quantum metrology scheme using bimodal optical fields that can achieve sub-Heisenberg precision, overcoming Markovian decoherence limitations through non-Markovian dynamics.

Contribution

It introduces a novel Gaussian quantum metrology approach that leverages non-Markovian effects to surpass traditional decoherence-induced precision limits.

Findings

Achieves sub-Heisenberg precision in ideal conditions.

Identifies Markovian decoherence as a source of divergence.

Demonstrates non-Markovian dynamics can mitigate decoherence effects.

Abstract

Quantum metrology pursues high-precision measurements of physical quantities by using quantum resources. However, the decoherence generally hinders its performance. Previous work found that the metrological error tends to diverge in the long-encoding-time regime due to the Born-Markovian approximate decoherence, which is called the no-go theorem of noisy quantum metrology. Here we propose a Gaussian quantum metrology scheme using bimodal quantized optical fields as the quantum probe. It achieves the precision of a sub-Heisenberg limit in the ideal case. However, the Markovian decoherence causes the metrological error contributed by the center-of-mass mode of the probe to be divergent. A mechanism to remove this ostensible no-go theorem is found in the non-Markovian dynamics. Our result gives an efficient way to realize high-precision quantum metrology in practical continuous-variable systems.