Protecting and enhancing spin squeezing from decoherence using weak measurements

Abstract

We propose an efficient method to protect spin squeezing under the action of amplitude-damping, depolarizing and phase-damping channels based on measurement reversal from weak measurement, and consider an ensemble of N independent spin-1/2 particles with exchange symmetry. We show that spin squeezing can be enhanced greatly under three different decoherence channels and spin-squeezing sudden death can be avoided undergoing amplitude-damping and phase-damping channels. Moreover, we find that the spin-squeezing parameters can be completely recovered to its initial value under amplitude-damping channel by changing weak measurement strength irrespective of sufficiently strong decoherence. For the phase-damping channel, the spin-squeezing parameter can be recovered to a certain stationary value in certain conditions. Our results provide an active way to suppress decoherence and enhance the spin squeezing under decoherence, which is rather significant for quantum metrology in open systems.