Quantum Metrology with Dicke Squeezed States

TL;DR

This paper introduces Dicke squeezed states, a new class of entangled states that enhance quantum measurement precision beyond the standard quantum limit, approaching the Heisenberg limit, and are robust against decoherence.

Contribution

The paper presents the concept of Dicke squeezed states, a novel class of entangled states with a measurable squeezing parameter that bounds entanglement depth and improves quantum metrology.

Findings

Dicke squeezed states can surpass the standard quantum limit in measurement precision.

The Dicke squeezing parameter $\xi_{D}$ bounds entanglement depth.

These states are more robust to decoherence compared to other entangled states.

Abstract

We introduce a new class of quantum many-particle entangled states, called the Dicke squeezed (or DS) states, which can be used to improve the precision in quantum metrology beyond the standard quantum limit. We show that the enhancement in measurement precision is characterized by a single experimentally detectable parameter, called the Dicke squeezing $\xi_{D}$, which also bounds the entanglement depth for this class of states. The measurement precision approaches the ultimate Heisenberg limit as $\xi_{D}$ attains the minimum in an ideal Dicke state. Compared with other entangled states, we show that the Dicke squeezed states are more robust to decoherence and give better measurement precision under typical experimental noise.