Engineering entanglement for metrology with rotating matter waves

TL;DR

This paper investigates the detailed structure and phase measurement capabilities of entangled rotating ultracold bosons beyond the lowest Landau level approximation, identifying new regimes for experimental quantum metrology.

Contribution

It demonstrates the importance of going beyond the LLL approximation to accurately characterize entangled states and quantum Fisher information in rotating ultracold bosons.

Findings

Beyond LLL, detailed state structure is identified.

Quantum Fisher information is quantified for phase measurement.

New parameter regimes for entangled state generation are proposed.

Abstract

Entangled states of rotating, trapped ultracold bosons form a very promising scenario for quantum metrology. In order to employ such states for metrology, it is vital to understand their detailed form and the enhanced accuracy with which they could measure phase, in this case generated through rotation. In this work we study the rotation of ultracold bosons in an asymmetric trapping potential beyond the lowest Landau level (LLL) approximation. We demonstrate that whilst the LLL can identify reasonably the critical frequency for a quantum phase transition and entangled state generation, it is vital to go beyond the LLL to identify the details of the state and quantify the quantum Fisher information (which bounds the accuracy of the phase measurement). We thus identify a new parameter regime for useful entangled state generation, amenable to experimental investigation.