We investigate the Unruh effect on entanglement taking into account the spin degree of freedom of the Dirac field. We analyze spin Bell states in this setting, obtaining their entanglement dependance on the acceleration of one of the partners. Then, we consider simple analogs to the occupation number entangled state |00>+|11>, but with spin quantum numbers for |11> showing that, despite their apparent similitude, while the spinless case is always qubit x qubit, for the spin case acceleration produces a qubit x qu4it state. We also introduce a procedure to consistently erase the spin information from our setting preserving occupation numbers. We show how the maximally entangled state for occupation number emerges from our setting, we also analyze its entanglement dependance on acceleration, obtaining a greater entanglement degradation than in the spinless case.
In quantum communication protocols the existence of a shared reference frame between two spatially separated parties is normally presumed. However, in many practical situations we are faced with the problem of misaligned reference frames. In this paper, we study communication between two inertial observers who have partial knowledge about the Lorentz transformation that relates their frames of reference. Since every Lorentz transformation can be decomposed into a pure boost followed by a rotation, we begin by analysing the effects on communication when the parties have partial knowledge about …
Non-Inertial Frames in Minkowski Space-Time, Accelerated either Mathematical or Dynamical Observers and Comments on Non-Inertial Relativistic Quantum Mechanics
In a recent paper (arXiv:1701.04298 [quant-ph]) Toroš, Großardt and Bassi claim that the potential necessary to support a composite particle in a gravitational field must necessarily cancel the relativistic coupling between internal and external degrees of freedom. As such a coupling is responsible for the gravitational redshift measured in numerous experiments, the above statement is clearly incorrect. We identify the simple mistake in the paper responsible for the incorrect claim.
Our recent paper (arXiv:1701.04298 [quant-ph]) discussed the occurrence of a coupling of centre of mass and internal degrees of freedom for complex quantum systems in non-inertial frames. There, we pointed out that an external force supporting the system against gravity plays a crucial role for the coupling between center of mass position to the internal degrees of freedom. In a comment (arXiv:1702.06670 [quant-ph]) to our paper, Pikovski et al. question our conclusion and present the argument that the lack of the coupling term would be in contradiction with the observation of gravitational ti…
A recent analysis by Pikovski et al. [Nat. Phys. 11, 668 (2015)] has triggered interest in the question of how to include relativistic corrections in the quantum dynamics governing many-particle systems in a gravitational field. Here we show how the center-of-mass motion of a quantum system subject to gravity can be derived more rigorously, addressing the ambiguous definition of relativistic center-of-mass coordinates. We further demonstrate that, contrary to the prediction by Pikovski et al., external forces play a crucial role in the relativistic coupling of internal and external degrees of …
The Minkowski vacuum $|0\rangle_M$, which for an inertial observer is devoid of particles, is treated as a thermal bath by Rindler observers living in a single Rindler wedge, as a result of the discrepancy in the definition of positive frequency between the two classes of observers and a strong entanglement between degrees of freedom in the left and right Rindler wedges. We revisit, in the context of a free scalar Klein-Gordon field, the problem of quantification of the correlations between an inertial observer Alice and left/right Rindler observes Rob/AntiRob. We emphasize the analysis of inf…
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 re…
We develop an extension of special relativity in $1+3$ dimensional spacetime to account for superluminal inertial observers and show that such an extension rules out the conventional dynamics of mechanical point-like particles and forces one to use a field-theoretic framework. Therefore we show that field theory can be viewed as a direct consequence of extended special relativity.
Entanglement of Dirac fields has been studied and it is known to decrease with increasing acceleration when a quantum state is shared between users in non-inertial frames. A new form of an entangled vacuum state observed by the accelerated observer is postulated in which it is assumed that entanglement is present between the modes of the quantum field with sharp and opposite momenta defined in two causally disconnected regions of space-time. We find that this assumption does not affect the entanglement of the system.
