Efficient Spin Squeezing with Optimized Pulse Sequences

TL;DR

This paper introduces an optimized quantum control scheme that significantly improves spin squeezing in spinor BECs and trapped ions, approaching the Heisenberg limit with practical, noise-robust pulse sequences.

Contribution

It proposes a new, experimentally feasible pulse sequence optimization method to enhance spin squeezing beyond traditional one-axis twisting schemes.

Findings

Achieves near-Heisenberg limit spin squeezing

Robust against technical noise

Applicable to current experimental platforms

Abstract

Spin squeezed states are a class of entangled states of spins that have practical applications to precision measurements. In recent years spin squeezing with one-axis twisting (OAT) has been demonstrated experimentally with spinor BECs with more than 10^3 atoms. Although the noise is below the standard quantum limit, the OAT scheme cannot reduce the noise down to the ultimate Heisenberg limit. Here we propose an experimentally feasible scheme based on optimized quantum control to greatly enhance the performance of OAT to approach the Heisenberg limit, requiring only an OAT Hamiltonian and the use of several coherent driving pulses. The scheme is robust against technical noise and can be readily implemented for spinor BECs or trapped ions with current technology.