Decoherence assisted spin squeezing generation in superposition of tripartite GHZ and W states

Abstract:In the present paper, we study spin squeezing under decoherence in the superposition of tripartite maximally entangled GHZ and W states. Here we use amplitude damping, phase damping and depolarisation channel. We have... [ view full abstract ]

Abstract:

In the present paper, we study spin squeezing under decoherence in the superposition of tripartite maximally entangled GHZ and W states. Here we use amplitude damping, phase damping and depolarisation channel. We have investigated the dynamics of spin squeezing with the interplay of superposition and decoherence parameters with different directions of the mean spin vector. We have found the mixture of GHZ and W states is robust against spin squeezing generation for amplitude damping and phase damping channels for certain directions of the mean spin vector. However, the depolarisation channel performs well for spin squeezing generation and generates permanent spin squeezing in the superposition of GHZ and W states.

Methods:

The decoherence dynamics has been studied under amplitude damping, phase damping and depolarization channel by using Kraus operators and spin squeezing generation have been investigated in terms of the qualities of these channels.

Results:

In the present study we have investigated the lucid signatures of spin squeezing generation in superposition of GHZ and W states under decoherence. We also have investigated the sensitive directions of the mean spin vector for which the spin squeezing generation do not take place. The superposition parameter $(\alpha=0.9)$ has been found sensitive, which do not support spin squeezing generation in both amplitude and phase damping channel. Amplitude damping and phase damping channels have an almost same impact on spin squeezing, while depolarization channel has a totally different paradigm. For depolarization channel, as the decoherence rate increases, the degree of squeezing slowly decay but never be zero. So we have found the depolarization channel is a good resource for generating permanent spin squeezing under decoherence in the superposition of GHZ and W states. The present study can also be upgraded to study the spin squeezing generation under particle loss along with decoherence in the superposition of GHZ and W states. So we mention the results obtained in the paper and discussion may be useful for quantum information processing community.

Figures: Few figures are attached.