39 research outputs found
Noisy Relativistic Quantum Games in Noninertial Frames
The influence of noise and of Unruh effect on quantum Prisoners' dilemma is
investigated both for entangled and unentangled initial states. The noise is
incorporated through amplitude damping channel. For unentangled initial state,
the decoherence compensates for the adverse effect of acceleration of the frame
and the effect of acceleration becomes irrelevant provided the game is fully
decohered. It is shown that the inertial player always out scores the
noninertial player by choosing defection. For maximally entangled initially
state, we show that for fully decohered case every strategy profile results in
either of the two possible equilibrium outcomes. Two of the four possible
strategy profiles become Pareto Optimal and Nash equilibrium and no dilemma is
leftover. It is shown that other equilibrium points emerge for different region
of values of decoherence parameter that are either Pareto optimal or Pareto
inefficient in the quantum strategic spaces. It is shown that the Eisert et al
miracle move is a special move that leads always to distinguishable results
compare to other moves. We show that the dilemma like situation is resolved in
favor of one player or the other.Comment: 14 pages and 6 figure
Cosmological quantum entanglement
We review recent literature on the connection between quantum entanglement
and cosmology, with an emphasis on the context of expanding universes. We
discuss recent theoretical results reporting on the production of entanglement
in quantum fields due to the expansion of the underlying spacetime. We explore
how these results are affected by the statistics of the field (bosonic or
fermionic), the type of expansion (de Sitter or asymptotically stationary), and
the coupling to spacetime curvature (conformal or minimal). We then consider
the extraction of entanglement from a quantum field by coupling to local
detectors and how this procedure can be used to distinguish curvature from
heating by their entanglement signature. We review the role played by quantum
fluctuations in the early universe in nucleating the formation of galaxies and
other cosmic structures through their conversion into classical density
anisotropies during and after inflation. We report on current literature
attempting to account for this transition in a rigorous way and discuss the
importance of entanglement and decoherence in this process. We conclude with
some prospects for further theoretical and experimental research in this area.
These include extensions of current theoretical efforts, possible future
observational pursuits, and experimental analogues that emulate these cosmic
effects in a laboratory setting.Comment: 23 pages, 2 figures. v2 Added journal reference and minor changes to
match the published versio
Effect of acceleration on information scrambling
The research subjects of information scrambling and the Unruh (anti-Unruh)
effect are closely associated with black hole physics. We study the impact of
acceleration on information scrambling under the Unruh (anti-Unruh) effect for
two types of tripartite entangled states, namely the GHZ and W states. Our
findings indicate that the anti-Unruh effect can result in stronger information
scrambling, as measured by tripartite mutual information (TMI). Additionally,
we show that the W state is more stable than the GHZ state under the influence
of uniformly accelerated motion. Lastly, we extend our analysis to -partite
entangled states and product states
Acceleration-assisted entanglement harvesting and rangefinding
We study entanglement harvested from a quantum field through local
interaction with Unruh-DeWitt detectors undergoing linear acceleration. The
interactions allow entanglement to be swapped locally from the field to the
detectors. We find an enhancement in the entanglement harvesting by two
detectors with anti-parallel acceleration over those with inertial motion. This
enhancement is characterized by the presence of entanglement between two
detectors that would otherwise maintain a separable state in the absence of
relativistic motion (with the same distance of closest approach in both cases).
We also find that entanglement harvesting is degraded for two detectors
undergoing parallel acceleration in the same way as for two static, comoving
detectors in a de Sitter universe. This degradation is known to be different
from that of two inertial detectors in a thermal bath. We comment on the
physical origin of the harvested entanglement and present three methods for
determining distance between two detectors using properties of the harvested
entanglement. Information about the separation is stored nonlocally in the
joint state of the accelerated detectors after the interaction; a single
detector alone contains none. We also find an example of entanglement sudden
death exhibited in parameter space.Comment: 17 pages, 6 figures. Version 2 updated to address referee comments
and minor correction