Sudden death and revival of Gaussian Einstein\u2013Podolsky\u2013Rosen steering in noisy channels

Xiaowei Deng,Meihong Wang,Xiaolong Su,Yang Liu,Kunchi Peng

doi:10.1038/s41534-021-00399-x

Xiaowei Deng, Meihong Wang + Show 3 more

Open Access

https://doi.org/10.1038/s41534-021-00399-x

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Abstract

Einstein–Podolsky–Rosen (EPR) steering is a useful resource for secure quantum information tasks. It is crucial to investigate the effect of inevitable loss and noise in quantum channels on EPR steering. We analyze and experimentally demonstrate the influence of purity of quantum states and excess noise on Gaussian EPR steering by distributing a two-mode squeezed state through lossy and noisy channels, respectively. We show that the impurity of state never leads to sudden death of Gaussian EPR steering, but the noise in quantum channel can. Then we revive the disappeared Gaussian EPR steering by establishing a correlated noisy channel. Different from entanglement, the sudden death and revival of Gaussian EPR steering are directional. Our result confirms that EPR steering criteria proposed by Reid and I. Kogias et al. are equivalent in our case. The presented results pave way for asymmetric quantum information processing exploiting Gaussian EPR steering in noisy environment.

Highlights

Nonlocality, which challenges our comprehension and intuition about the nature, is a key and distinctive feature of quantum world
The one-way EPR steering has been observed for both continuous variable (CV)[9,10,11,12,13] and discrete variable (DV) systems[14,15,16,17]
We show that in a lossy channel, the impurity of the state leads to decrease of steerabilities and two-way steering region, but it never leads to sudden death of Gaussian EPR steering

Summary

Introduction

Nonlocality, which challenges our comprehension and intuition about the nature, is a key and distinctive feature of quantum world. There is a situation that a quantum state may be steerable from Alice to Bob, but not vice versa, which is called the one-way steering[9,10,11,12,13,14,15,16,17]. This intriguing feature comes from the intrinsically asymmetric with respect to the two subsystems. When considering generally bipartite Gaussian states and using Gaussian measurements, the steerability between the submodes is referred as Gaussian steering. EPR steering has been identified as an essential resource for one-sided device-independent quantum key distribution[25,26,27], quantum secret sharing[28,29], secure quantum teleportation[30,31,32], securing quantum networking tasks[33], and subchannel discrimination[34,35]

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