Relativistic Quantum Information
I discuss the behaviour of bipartite and
tripartite non-locality between fermionic entangled states shared by observers,
one of whom uniformly accelerates. Although fermionic entanglement persists for
arbitrarily large acceleration, the Bell/CHSH inequalities cannot be violated
for sufficiently large but finite acceleration. However the Svetlichny
inequality, which is a measure of genuine tripartite non-locality, can be violated
for any finite value of the acceleration.
I review the recent work performed on computing the geometric
discord in non-inertial frames. We consider the well-known case of an
inertially maximally entangled state shared by inertial Alice and non-inertial
Robb. It is found that for high accelerations the geometric discord decays to a
negligible amount; this is in stark contrast to the entropic definition of
quantum discord which asymptotes to a finite value in the same limit. Such a
result has two different implications: the first being that usable quantum
We consider quantum teleportation of continuous variables in a relativistic system with the Unruh-DeWitt detectorscoupled to a common quantum field initially in the Minkowski vacuum. An unknown coherent state of an Unruh-DeWitt detector is teleported from one inertial agent (Alice) to an almost uniformly accelerated agent (Rob), using a detector pair initially entangled and shared by these two agents. Results for the averaged physical fidelity of quantum teleportation will be discussed.
A number of works in the field of relativistic quantum information have been devoted to the study of entanglement on certain simple families of Unruh-mode entangled states in non-inertial frames. In the fermionic case remarkable results such as the survival of entanglement at infinite acceleration have been obtained.
We discuss gedanken
experiments for measuring local and non-local observables in QFT that
respect causality, and can by used to test the entanglement between two spatially distant regions in the vacuum. It is shown that the entanglement
decays exponentially with the distance between the regions and does not vanish, in contrast to the
case of lattice models. We discuss in this respect a possible mechanism which might
explain this persistence effect, and a connection between the Reeh-Schlieder
theorem and superoscillations.
This talk aims to review the obstacles met in QFT to
reach an appropriate definition for such a basic concept as localization. The
anti-local character of the square root of the "- Laplace-Beltrami +
mass^2" operator prevents the existence of localized states with a finite
number of quanta. (Bosonic) quantum fields describe elementary excitations of
an extended system whose ground state is the vacuum. No wonder, there is a
complicated relationship between the cardinal