Supersensitive quantum sensor based on criticality in an antiferromagnetic spinor condensate

TL;DR

This paper proposes a quantum sensor utilizing critical phenomena in an antiferromagnetic spinor Bose-Einstein condensate, achieving supersensitive parameter estimation with precision scaling up to N^4, even considering low-temperature effects.

Contribution

It introduces a novel quantum sensing scheme based on criticality in spinor condensates, demonstrating supersensitivity and high-precision measurement capabilities.

Findings

Precision scales with the number of atoms up to N^4 near critical points.

Supersensitivity is demonstrated using quantum Fisher information.

Sub-shot noise sensitivity is achievable at low temperatures.

Abstract

We consider an antiferromagnetic Bose-Einstein condensate in a traverse magnetic field with a fixed macroscopic magnetization. The system exhibits two different critical behaviors corresponding to transitions from polar to broken-axisymmetry and from antiferromagnetic to broken-axisymmetry phases depending on the value of magnetization. We exploit both types of system criticality as a resource in the precise estimation of control parameter value. We quantify the achievable precision by the quantum Fisher information. We demonstrate supersensitivity and show that the precision scales with the number of atoms up to $N^4$ around critically. In addition, we study the precision based on the error-propagation formula providing the simple-to-measure signal which coincides its scaling with the quantum Fisher information. Finally, we take into account the effect of non-zero temperature and show that the sub-shot noise sensitivity in the estimation of the control parameter is achievable in the low-temperature limit.