Engineering asymmetric steady-state Einstein-Podolsky-Rosen steering in macroscopic hybrid systems

Abstract

Generation of quantum correlations between separate objects is of significance both in fundamental physics and in quantum networks. One important challenge is to create the directional "spooky action-at-a-distance" effects that Schrödinger called "steering" between two macroscopic and massive objects. Here, we analyze a generic scheme for generating steering correlations in cascaded hybrid systems in which two distant oscillators with effective masses of opposite signs are coupled to a unidirectional light field, a setup which is known to build up quantum correlations by means of quantum back-action evasion. The unidirectional coupling of the first to the second oscillator via the light field can be engineered to enhance steering in both directions and provides an active method for controlling the asymmetry of steering. We show that the resulting scheme can efficiently generate unconditional steady-state Einstein-Podolsky-Rosen steering between the two subsystems, even in the presence of thermal noise and optical losses. As a scenario of particular technological interest in quantum networks, we use our scheme to engineer enhanced steering from an untrusted node with limited tunability (in terms of interaction strength and type with the light field) to a trusted, highly tunable node, hence offering a path to implementing one-sided device-independent quantum tasks.Here the optical vacuum field is described by the operator b(t) ≡b l (t) +b u (t) = (2π) −1/2 (

Certification and applications of quantum nonlocal correlations

“…For two-qubit states, a theoretical and experimental certification of one-way steering with no assumptions on state fidelity or measurement settings have been performed [103]. Since this asymmetry can be detected in several systems, a proposal for generating asymmetric steering in macroscopic steering is given in [104].…”

Einstein-Podolsky-Rosen steering of quantum phases in a cavity Bose-Einstein condensate with a single impurity

“…Bipartite asymmetry EPR steering was also investigated in the cascaded third and fourth-harmonic generation process [25,26] , respectively. Experimentally, EPR steering has been tested in various physical systems [43][44][45][46][47][48][49][50][51][52]. For instance, Tischler et al [46] gave a conclusive experimental demonstration of one-way steering.…”

“…Fadel et al [49] observed spatial entanglement patterns and EPR steering in Bose-Einstein condensates. Huang et al [50] demonstrated that one can generate and control the asymmetry of steady-state EPR steering by engineering asymmetric couplings to the optical field. Li et al [51] demonstrated quantum steering of orbital angular momentum multiplexed optical fields.…”

Some Measurement-Based Characterizations of Separability of Bipartite States

“…As an intermediary property between Bell nonlocality and entanglement, EPR steering was first observed by Schrödinger [2] in the context of the well-known EPR paradox [1,[20][21][22]. It is also is an important resources in quantum information and then has been recently discussed, please refer to [17,[23][24][25][26][27][28][29][30][31]. Especially, mathematical definitions of Bell nonlocality and EPR steerability of bipartite states were proposed and their characterizations were given in [17] by Cao and Guo. Although entanglement was first recognized as the characteristic trait of quantum mechanics [1], its role has been debated since it does not capture all the quantum features of a quantum system [32][33][34].…”