Preserving coherent spin and squeezed spin states of a spin-1 Bose-Einstein condensate with rotary echoes

Abstract

A challenge in precision measurement with squeezed spin state arises from the spin dephasing due to stray magnetic fields. To suppress such environmental noises, we employ a continuous driving protocol, rotary echo, to enhance the spin coherence of a spin-1 Bose-Einstein condensate in stray magnetic fields. Our analytical and numerical results show that the coherent and the squeezed spin states are preserved for a significantly long time, compared to the free induction decay time, if the condition $h\tau =m\pi$ is met with $h$ the pulse amplitude and $\tau$ pulse width. In particular, both the spin average and the spin squeezing, including the direction and the amplitude, are simultaneously fixed for a squeezed spin state. Our results point out a practical way to implement quantum measurements based on a spin-1 condensate beyond the standard quantum limit.

8 pages, 6 eps color figures, RevTex 4

References in corpus (7)

• Twin matter waves for interferometry beyond the classical limit
• Scalable Spin Squeezing for Quantum-Enhanced Magnetometry with Bose-Einstein Condensates
• High-Resolution Magnetometry with a Spinor Bose-Einstein Condensate
• Spin squeezing: transforming one-axis-twisting into two-axis-twisting
• Coherent magnon optics in a ferromagnetic spinor Bose-Einstein condensate
• Decay of the rotary echoes for the spin of a nitrogen-vacancy center in diamond
• Protecting the $\sqrt{SWAP}$ operation from general and residual errors by continuous dynamical decoupling

Cited by in corpus (1)

• Rebuilding of destroyed spin squeezing in noisy environments