Spatio-Temporal Steering for Testing Nonclassical Correlations in Quantum Networks

Shin-Liang Chen,Guang-Yin Chen,Franco Nori,Che-Ming Li,Neill Lambert,Yueh-Nan Chen,Adam Miranowicz

doi:10.1038/s41598-017-03789-4

Abstract

We introduce the concept of spatio-temporal steering (STS), which reduces, in special cases, to Einstein-Podolsky-Rosen steering and the recently-introduced temporal steering. We describe two measures of this effect referred to as the STS weight and robustness. We suggest that these STS measures enable a new way to assess nonclassical correlations in an open quantum network, such as quantum transport through nano-structures or excitation transfer in a complex biological system. As one of our examples, we apply STS to check nonclassical correlations among sites in a photosynthetic pigment-protein complex in the Fenna-Matthews-Olson model.

Highlights

Nonclassical temporal correlations play a fundamental role in quantum optics research, since the Hanbury-Brown and Twiss experiments[36] and the Glauber theory of quantum coherence[37]
If one replaces the assumption (A2) with (A2’), which means that during each moment of time the system can be described by a quantum state σλ, which is determined by some hidden variables λ independent of the measurements performed before, the hidden variables determine the observed data table p(a x) = ∑λ p(λ)p(a x, λ) at time t = 0, and a priori the quantum state ρ = ∑λ p(λ)σλ at time t
The concept of spatio-temporal quantum entanglement is fundamentally difficult to be described consistently, we showed that spatio-temporal steering (STS), describing a certain type of spatio-temporal nonclassical correlations, can be defined and quantified in an operational way

Summary

Introduction

Nonclassical temporal correlations (like photon antibunching) play a fundamental role in quantum optics research, since the Hanbury-Brown and Twiss experiments[36] and the Glauber theory of quantum coherence[37]. Note that STS can be applied to test quantum-state transfer in quantum networks like those described in refs 49, 50. Quantum mechanics predicts some assemblages, which do not admit the temporal hidden-state model, and we refer to this situation as temporal steering[44].

Results

Conclusion