Continuous-variable quantum teleportation with vacuum-entangled Rindler modes

Abstract

We consider a continuous-variable quantum teleportation protocol between a uniformly accelerated sender in the right Rindler wedge, a conformal receiver restricted to the future light cone, and an inertial observer in the Minkowski vacuum. Using a non-perturbative quantum circuit model, the accelerated observer interacts unitarily with the Rindler modes of the field, thereby accessing entanglement of the vacuum as a resource. We find that a Rindler-displaced Minkowski vacuum state prepared and teleported by the accelerated observer appears mixed according to the inertial observer, despite a reduction of the quadrature variances below classical limits. This is a surprising result, since the same state transmitted directly from the accelerated observer appears as a pure coherent state to the inertial observer. The decoherence of the state is caused by an interplay of opposing effects as the acceleration increases: the reduction of vacuum noise in the output state for a stronger entanglement resource, constrained by the amplification of thermal noise due to the presence of Unruh radiation.

Telefilters, telemirrors, and causality

“…The aims of this paper have been threefold. Firstly, we proposed a new teleportation model for the mode-selective mirror, which is widely used in quantum information and communication [4][5][6], relativistic QFT [9][10][11][12][13][14] and experimental applications in quantum optics [15][16][17][18].…”

“…Apart from this difference, the two approaches are functionally equivalent in terms of the teleported beam. Notably, the all-optical protocol has been recently realised in experiment [43] and has also been recently studied in the context of relativistic, noninertial observers [12]. The circuit diagram for the protocol is shown in equivalent approach to the previous case studied, using homodyne measurements.…”

“…Mode-selective mirrors and beamsplitters have been identified as key tools in future communications and metrology applications [4][5][6][7][8]. Other mode-discriminating interactions such as phase-shifters, displacements and squeezers have been studied in the context of relativistic quantum communication protocols [9][10][11][12][13][14] describing interactions between quantum fields and observers in relativistic reference frames.…”

Is quantum teleportation beyond horizon possible?

“…On the other hand, quantum teleportation in the opposite direction, i.e., from an accelerated observer to an inertial observer, was considered very recently in Ref. [18] in the context of continuous variable scheme, rather than qubits, while involving a beam-splitter with timedependent reflectivity in the future Rindler wedge. It is shown in Ref.…”

“…It is shown in Ref. [18] that the output state obtained by the inertial observer is polluted by thermal noise. The introduction of the time-dependent reflectivity of the beam-splitter was motivated from the quantization in the future Rindler wedge [19,20], which is performed with respect to a timelike conformal Killing vector, rather than a timelike Killing vector, and thus a detector that probes the quantum particles in the future Rindler wedge will need to have time-dependent excitation energy [19], or equivalently it should expand as time elapses [21].…”