scholarly journals Ellis wormholes in anti-de Sitter space

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Jose Luis Blázquez-Salcedo ◽  
Xiao Yan Chew ◽  
Jutta Kunz ◽  
Dong-han Yeom
Keyword(s):  
De Sitter Space ◽  
Radial Mode ◽  
Radial Coordinate ◽  
De Sitter ◽  
Asymptotically Flat ◽  
Phantom Field ◽  
Traversable Wormholes

AbstractWe construct traversable wormholes with anti-de Sitter asymptotics supported by a phantom field. These wormholes are massless and symmetric with respect to reflection of the radial coordinate $$\eta \rightarrow - \eta $$ η → - η . Their circumferential radius decreases monotonically from radial infinity to their single throat. Analogous to their asymptotically flat counterparts, these anti-de Sitter wormholes possess an unstable radial mode.

scholarly journals Traversable wormholes in Einsteinian cubic gravity

2019 ◽  
Vol 35 (06) ◽  
pp. 2050017 ◽  
Author(s):  
Mohammad Reza Mehdizadeh ◽  
Amir Hadi Ziaie
Keyword(s):  
Equation Of State ◽  
Gravitational Lensing ◽  
Energy Condition ◽  
Higher Order ◽  
Energy Conditions ◽  
Geodesic Motion ◽  
De Sitter ◽  
Asymptotically Flat ◽  
Traversable Wormholes ◽  
Standard Energy

In this work, we investigate wormhole configurations described by a constant redshift function in Einstein-Cubic gravity ( ECG ). We derive analytical wormhole geometries by assuming a particular equation of state ( EoS ) and investigate the possibility that these solutions satisfy the standard energy conditions. We introduce exact asymptotically flat and anti-de Sitter (AdS) spacetimes that admit traversable wormholes. These solutions are obtained by imposing suitable values for the parameters of the theory so that the resulted geometries satisfy the weak energy condition ( WEC ) in the vicinity of the throat, due to the presence of higher-order curvature terms. Moreover, we find that AdS solutions satisfy the WEC throughout the spacetime. A description of the geodesic motion of time-like and null particles is presented for the obtained wormhole solutions. Also, using gravitational lensing effects, observational features of the wormhole structure are discussed.

scholarly journals Traversable wormholes in the bulge of Milky Way galaxy with Global Monopole Charge

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Susmita Sarkar ◽  
Nayan Sarkar ◽  
Farook Rahaman
Keyword(s):  
Milky Way ◽  
Shape Function ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Radial Coordinate ◽  
Global Monopole ◽  
Milky Way Galaxy ◽  
Asymptotically Flat ◽  
Traversable Wormholes ◽  
Crucial Effect

AbstractThe present work looks for the existence of completely new wormhole geometries in the bulge of the Milky Way galaxy (MWG) situated on the dark matter (DM) density profile followed from MacMillan (MNRAS 76:465, 2017) and Boshkayev and Malafarina (MNRAS 484:3325, 2019) concerned with Global Monopole Charge. The obtained shape function is positively increasing against the radial coordinate and it increases faster with the increasing values of Global Monopole Charge. Moreover, the reported shape function satisfies all the essential criterions and hence it constructs wormhole geometry in the bulge of the MWG. Further, the DM candidate around bulge is suitable to harbor wormhole by violating the null energy condition(NEC) corresponding to three different redshift functions. The striking point of our solution is that for zero Global Monopole Charge the wormholes are asymptotically flat corresponding to the first two choices of redshift functions while for positive values of Global Monopole Charge wormhole becomes non asymptotically flat and Global Monopole Charge also has the crucial effect on the violation of NEC. In our solutions, one can note that the total amount of averaged NEC violating matter in the wormhole spacetime depends on the Global Monopole Charge $$\eta $$ η . Furthermore, the respective wormhole solutions are in equilibrium positions.

scholarly journals Gravitational turbulent instability of anti-de Sitter space

2012 ◽  
Vol 29 (19) ◽  
pp. 194002 ◽  
Author(s):  
Óscar J C Dias ◽  
Gary T Horowitz ◽  
Jorge E Santos
Keyword(s):  
De Sitter Space ◽  
De Sitter

scholarly journals Hamiltonian charges in the asymptotically de Sitter spacetimes

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Maciej Kolanowski ◽  
Jerzy Lewandowski
Keyword(s):  
Phase Space ◽  
Initial Data ◽  
Exact Solutions ◽  
Gravitational Waves ◽  
Physical Meaning ◽  
De Sitter ◽  
Killing Vectors ◽  
Asymptotically Flat ◽  
Angular Momenta ◽  
The One

Abstract We generalize a notion of ‘conserved’ charges given by Wald and Zoupas to the asymptotically de Sitter spacetimes. Surprisingly, our construction is less ambiguous than the one encountered in the asymptotically flat context. An expansion around exact solutions possessing Killing vectors provides their physical meaning. In particular, we discuss a question of how to define energy and angular momenta of gravitational waves propagating on Kottler and Carter backgrounds. We show that obtained expressions have a correct limit as Λ → 0. We also comment on the relation between this approach and the one based on the canonical phase space of initial data at ℐ+.

scholarly journals Open quantum entanglement: a study of two atomic system in static patch of de Sitter space

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Samim Akhtar ◽  
Sayantan Choudhury ◽  
Satyaki Chowdhury ◽  
Debopam Goswami ◽  
Sudhakar Panda ◽  
...  
Keyword(s):  
Scalar Field ◽  
Density Matrix ◽  
Master Equation ◽  
Quantum Entanglement ◽  
De Sitter Space ◽  
Thermal Bath ◽  
Massless Scalar Field ◽  
De Sitter ◽  
Open Quantum ◽  
Non Locality

Abstract In this work, our prime objective is to study non-locality and long range effect of two body correlation using quantum entanglement from various information theoretic measure in the static patch of de Sitter space using a two body Open Quantum System (OQS). The OQS is described by a system of two entangled atoms, surrounded by a thermal bath, which is modelled by a massless probe scalar field. Firstly, we partially trace over the bath field and construct the Gorini Kossakowski Sudarshan Lindblad (GSKL) master equation, which describes the time evolution of the reduced subsystem density matrix. This GSKL master equation is characterized by two components, these are-Spin chain interaction Hamiltonian and the Lindbladian. To fix the form of both of them, we compute the Wightman functions for probe massless scalar field. Using this result alongwith the large time equilibrium behaviour we obtain the analytical solution for reduced density matrix. Further using this solution we evaluate various entanglement measures, namely Von-Neumann entropy, R$$e'$$e′nyi entropy, logarithmic negativity, entanglement of formation, concurrence and quantum discord for the two atomic subsystem on the static patch of De-Sitter space. Finally, we have studied violation of Bell-CHSH inequality, which is the key ingredient to study non-locality in primordial cosmology.

scholarly journals Probing Planckian physics in de Sitter space with quantum correlations

2014 ◽  
Vol 351 ◽  
pp. 872-899 ◽  
Author(s):  
Jun Feng ◽  
Yao-Zhong Zhang ◽  
Mark D. Gould ◽  
Heng Fan ◽  
Cheng-Yi Sun ◽  
...  
Keyword(s):  
De Sitter Space ◽  
Quantum Correlations ◽  
De Sitter
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