Entanglement of arbitrary spin modes in an expanding universe (original) (raw)
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Entanglement of arbitrary spin modes in expanding universe
Quantum Information Processing, 2015
Pair particle creation is a well-known effect on the domain of field theory in curved space-time. It is shown that the entanglement generations for spin-0 and spin-1/2 modes are different in Friedmann-Robertson-Walker (FRW) space-time. We consider the spin-1 particles in FRW space-time using Duffin-Kemmer-Petiao (DKP) equation and obtain a measure of the generated entanglement. Also, we consider the spin-3/2 particles. We argue that the absolute value of the spin does not play any role in entanglement generation and the differences are due to the bosonic or fermionic properties.
Entanglement of Dirac fields in an expanding spacetime
Physical Review D, 2010
We study the entanglement generated between Dirac modes in a 2-dimensional conformally flat Robertson-Walker universe. We find radical qualitative differences between the bosonic and fermionic entanglement generated by the expansion. The particular way in which fermionic fields get entangled encodes more information about the underlying space-time than the bosonic case, thereby allowing us to reconstruct the parameters of the history of the expansion. This highlights the importance of bosonic/fermionic statistics to account for relativistic effects on the entanglement of quantum fields.
Entanglement generation in relativistic quantum fields
Journal of Modern Optics, 2013
We present a general, analytic recipe to compute the entanglement that is generated between arbitrary, discrete modes of bosonic quantum fields by Bogoliubov transformations. Our setup allows the complete characterization of the quantum correlations in all Gaussian field states. Additionally, it holds for all Bogoliubov transformations. These are commonly applied in quantum optics for the description of squeezing operations, relate the mode decompositions of observers in different regions of curved spacetimes, and describe observers moving along nonstationary trajectories. We focus on a quantum optical example in a cavity quantum electrodynamics setting: an uncharged scalar field within a cavity provides a model for an optical resonator, in which entanglement is created by non-uniform acceleration. We show that the amount of generated entanglement can be magnified by initial single-mode squeezing, for which we provide an explicit formula. Applications to quantum fields in curved spacetimes, such as an expanding universe, are discussed.
Quantum thermodynamics and quantum entanglement entropies in an expanding universe
International Journal of Modern Physics A
We investigate an asymptotically spatially flat Robertson–Walker space–time from two different perspectives. First, using von Neumann entropy, we evaluate the entanglement generation due to the encoded information in space–time. Then, we work out the entropy of particle creation based on the quantum thermodynamics of the scalar field on the underlying space–time. We show that the general behavior of both entropies are the same. Therefore, the entanglement can be applied to the customary quantum thermodynamics of the universe. Also, using these entropies, we can recover some information about the parameters of space–time.
Entanglement of self-interacting scalar fields in an expanding spacetime
EPL (Europhysics Letters), 2016
We evaluate self-interaction effects on the quantum correlations of field modes of opposite momenta for scalar λφ 4 theory in a two-dimensional asymptotically flat Robertson-Walker spacetime. Such correlations are encoded both in the von-Neumann entropy defined through the reduced density matrix in one of the modes and in the covariance expressed in terms of the expectation value of the number operators for each mode in the evolved state. The entanglement between field modes carries information about the underlying spacetime evolution.
Entanglement of arbitrary spin fields in noninertial frames
2011
We generalize the study of fermionic and bosonic entanglement in noninertial frames to fields of arbitrary spin and beyond the single-mode approximation. After the general analysis we particularize for two interesting cases: entanglement between an inertial and an accelerated observer for massless fields of spin 1 (electromagnetic) and spin 3/2 (Rarita-Schwinger). We show that, in the limit of infinite acceleration, no significant differences appear between the different spin fields for the states considered.
Generation and evolution of spin entanglement in nonrelativistic QED
Physical Review A, 2003
Analysis on the generation of spin entanglement from non-relativistic QED is presented. The results of entanglement are obtained with relativistic correction to the leading order of ( v c ) 2 . It is shown that to this order the degree of entanglement of a singlet state does not change under time evolution whereas the triplet state can change.
Dirac fermion, cosmological event horizons, and quantum entanglement
Physical Review D
We discuss the field quantization of a free massive Dirac fermion in the two causally disconnected static patches of the de Sitter spacetime, by using mode functions that are normalizable on the cosmological event horizon. Using this, we compute the entanglement entropy of the vacuum state corresponding to these two regions, for a given fermionic mode. Further extensions of this result to more general static spherically symmetric and stationary axisymmetric spacetimes are discussed. For the stationary axisymmetric Kerr-de Sitter spacetime in particular, the variations of the entanglement entropy with respect to various eigenvalues and spacetime parameters are depicted numerically. We also comment on such variations when instead we consider the nonextremal black hole event horizon of the same spacetime.
2020
We investigate the matching point between non-inertial frames and local inertial frames. This localization of gravity lead to an emergence of a timeless state of the universe in a mathematically consistent way. I find a geometric interpretation of the speed of light and mass. I find also a relation between every mass measured and the black hole entropy which introduces an information-matter equation from gravity. The experimental evidence of the timeless state of the universe is the quantum entanglement. Since the spin measurement is the manifestation of quantum entanglement measurement. Therefore, the spin of quantum particle can be understood as a relative gravitational red-shift. Therefore the spin quantum number is understood as a quantum gravity measurement in local inertial frames. We introduce also guidance that leads to the least computations of gravitational measurement which is achieved when the ratio equal to the difference.
Preprint typeset in JHEP style- HYPER VERSION arXiv:1304.nnnn [hep-th] On Spacetime Entanglement
2016
Abstract: We examine the idea that in quantum gravity, the entanglement entropy of a general region should be finite and the leading contribution is given by the Bekenstein-Hawking area law. Using holographic entanglement entropy calculations, we show that this idea is realized in the Randall-Sundrum II braneworld for sufficiently large regions in smoothly curved backgrounds. Extending the induced gravity action on the brane to include the curvature-squared interactions, we show that the Wald entropy closely matches the expression describing the entanglement entropy. The difference is that for a general region, the latter includes terms involving the extrinsic curvature of the entangling surface, which do not appear in the Wald entropy. We also consider various limitations on the validity of these results. ar X iv