Squeezing and overcoming the Heisenberg scaling with spin-orbit coupled quantum gases

TL;DR

This paper demonstrates that spin-orbit coupling in quantum gases can enable measurement precision scaling beyond the Heisenberg limit by using squeezed states and entangled many-body states, with potential robustness to temperature effects.

Contribution

It introduces a novel protocol leveraging spin-orbit coupling and entanglement to surpass traditional quantum measurement limits in atomic gases.

Findings

Quadratic scaling of measurement precision with atom number.

Overcoming the Heisenberg limit using tailored many-body states.

Finite temperature can be advantageous for precision scaling.

Abstract

We predict that exploiting spin-orbit coupling in a harmonically trapped spinor quantum gas can lead to scaling of the optimal measurement precision beyond the Heisenberg scaling. We show that quadratic scaling with the number of atoms can be facilitated via squeezed center-of-mass excitations of the atomic motion using a 1D spin-orbit coupled fermions or strongly interacting bosons (Tonks-Girardeau gas). Based on predictions derived from analytic calculations of the corresponding quantum Fisher information, we then introduce a protocol which overcomes the Heisenberg scaling (and limit) with help of a tailored excited and entangled many-body state of a non-interacting Bose-Einstein condensate. We identify corresponding optimal measurements and argue that even finite temperature as a source of decoherence is, in principle, rather favorable for the obtainable precision scaling.