scholarly journals Soft photon theorem in the small negative cosmological constant limit

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Nabamita Banerjee ◽  
Karan Fernandes ◽  
Arpita Mitra
Keyword(s):  
Cosmological Constant ◽  
Tree Level ◽  
Leading Order ◽  
Asymptotically Flat ◽  
Soft Factor ◽  
Flat Spacetime ◽  
Electromagnetic Interactions ◽  
Flat Spacetimes ◽  
Perturbative Corrections ◽  
Soft Factors

Abstract We study the effect of electromagnetic interactions on the classical soft theorems on an asymptotically AdS background in 4 spacetime dimensions, in the limit of a small cosmological constant or equivalently a large AdS radius l. This identifies 1/l2 perturbative corrections to the known asymptotically flat spacetime leading and subleading soft factors. Our analysis is only valid to leading order in 1/l2. The leading soft factor can be expected to be universal and holds beyond tree level. This allows us to derive a 1/l2 corrected Ward identity, following the known equivalence between large gauge Ward identities and soft theorems in asymptotically flat spacetimes.

scholarly journals A Sharp Version of Price’s Law for Wave Decay on Asymptotically Flat Spacetimes

2021 ◽  
Author(s):  
Peter Hintz
Keyword(s):  
Order Term ◽  
Angular Frequency ◽  
Leading Order ◽  
Full Generality ◽  
Asymptotically Flat ◽  
Low Energies ◽  
Flat Spacetimes ◽  
Explicit Constant ◽  
Sharp Version ◽  
Linear Scalar

AbstractWe prove Price’s law with an explicit leading order term for solutions $$\phi (t,x)$$ ϕ ( t , x ) of the scalar wave equation on a class of stationary asymptotically flat $$(3+1)$$ ( 3 + 1 ) -dimensional spacetimes including subextremal Kerr black holes. Our precise asymptotics in the full forward causal cone imply in particular that $$\phi (t,x)=c t^{-3}+{\mathcal {O}}(t^{-4+})$$ ϕ ( t , x ) = c t - 3 + O ( t - 4 + ) for bounded |x|, where $$c\in {\mathbb {C}}$$ c ∈ C is an explicit constant. This decay also holds along the event horizon on Kerr spacetimes and thus renders a result by Luk–Sbierski on the linear scalar instability of the Cauchy horizon unconditional. We moreover prove inverse quadratic decay of the radiation field, with explicit leading order term. We establish analogous results for scattering by stationary potentials with inverse cubic spatial decay. On the Schwarzschild spacetime, we prove pointwise $$t^{-2 l-3}$$ t - 2 l - 3 decay for waves with angular frequency at least l, and $$t^{-2 l-4}$$ t - 2 l - 4 decay for waves which are in addition initially static. This definitively settles Price’s law for linear scalar waves in full generality. The heart of the proof is the analysis of the resolvent at low energies. Rather than constructing its Schwartz kernel explicitly, we proceed more directly using the geometric microlocal approach to the limiting absorption principle pioneered by Melrose and recently extended to the zero energy limit by Vasy.

scholarly journals Soft theorems from boundary terms in the classical point particle currents

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Colby DeLisle ◽  
Jordan Wilson-Gerow ◽  
Philip Stamp
Keyword(s):  
Scalar Field ◽  
Quantum Gravity ◽  
Stress Tensor ◽  
Point Particle ◽  
Tree Level ◽  
Leading Order ◽  
Soft Factor ◽  
Boundary Terms ◽  
Perturbative Quantum ◽  
Classical Point

Abstract Soft factorization has been shown to hold to sub-leading order in QED and to sub-sub-leading order in perturbative quantum gravity, with various loop and non-universal corrections that can be found. Here we show that all terms factorizing at tree level can be uniquely identified as boundary terms that exist already in the classical expressions for the electric current and stress tensor of a point particle. Further, we show that one cannot uniquely identify such boundary terms beyond the sub-leading or sub-sub-leading orders respectively, providing evidence that the factorizability of the tree level soft factor only holds to these orders. Finally, we show that these boundary terms factor out of all tree level amplitudes as expected, in a theory where gravitons couple to a scalar field.

scholarly journals Classical Soft Theorem in the AdS-Schwarzschild spacetime in small cosmological constant limit

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Nabamita Banerjee ◽  
Arindam Bhattacharjee ◽  
Arpita Mitra
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Mass Parameter ◽  
Flat Space ◽  
Leading Order ◽  
Probe Particle ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Soft Factor ◽  
Soft Limit

Abstract We have studied scattering of a probe particle by a four dimensional AdS-Schwarzschild black hole at large impact factor. Our analysis is consistent perturbatively to leading order in the AdS radius and black hole mass parameter. Next we define a proper “soft limit” of the radiation and extract out the “soft factor” from it. We find the correction to the well known flat space Classical Soft graviton theorem due to the presence of an AdS background.

scholarly journals BMS field theories and Weyl anomaly

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Arjun Bagchi ◽  
Sudipta Dutta ◽  
Kedar S. Kolekar ◽  
Punit Sharma
Keyword(s):  
Three Dimensions ◽  
Field Theories ◽  
Partition Functions ◽  
Two Dimensional ◽  
Speed Of Light ◽  
Asymptotically Flat ◽  
Weyl Invariance ◽  
Flat Spacetimes ◽  
Liouville Action ◽  
Null Surfaces

Abstract Two dimensional field theories with Bondi-Metzner-Sachs symmetry have been proposed as duals to asymptotically flat spacetimes in three dimensions. These field theories are naturally defined on null surfaces and hence are conformal cousins of Carrollian theories, where the speed of light goes to zero. In this paper, we initiate an investigation of anomalies in these field theories. Specifically, we focus on the BMS equivalent of Weyl invariance and its breakdown in these field theories and derive an expression for Weyl anomaly. Considering the transformation of partition functions under this symmetry, we derive a Carrollian Liouville action different from ones obtained in the literature earlier.

scholarly journals Islands and stretched horizon

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Yoshinori Matsuo
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hawking Radiation ◽  
Entanglement Entropy ◽  
Total System ◽  
Island Rule ◽  
Asymptotically Flat ◽  
Flat Spacetime ◽  
Ads Spacetime ◽  
Hole Geometry

Abstract Recently it was proposed that the entanglement entropy of the Hawking radiation contains the information of a region including the interior of the event horizon, which is called “island.” In studies of the entanglement entropy of the Hawking radiation, the total system in the black hole geometry is separated into the Hawking radiation and black hole. In this paper, we study the entanglement entropy of the black hole in the asymptotically flat Schwarzschild spacetime. Consistency with the island rule for the Hawking radiation implies that the information of the black hole is located in a different region than the island. We found an instability of the island in the calculation of the entanglement entropy of the region outside a surface near the horizon. This implies that the region contains all the information of the total system and the information of the black hole is localized on the surface. Thus the surface would be interpreted as the stretched horizon. This structure also resembles black holes in the AdS spacetime with an auxiliary flat spacetime, where the information of the black hole is localized at the interface between the AdS spacetime and the flat spacetime.

scholarly journals Observations of Hawking radiation: the Page curve and baby universes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Donald Marolf ◽  
Henry Maxfield
Keyword(s):  
Black Holes ◽  
Quantum Systems ◽  
Late Time ◽  
Asymptotically Flat ◽  
Black Hole Information ◽  
Flat Spacetimes ◽  
The Cost ◽  
Baby Universes ◽  
Time Extrapolation ◽  
Asymptotic Observers

AbstractWe reformulate recent insights into black hole information in a manner emphasizing operationally-defined notions of entropy, Lorentz-signature descriptions, and asymptotically flat spacetimes. With the help of replica wormholes, we find that experiments of asymptotic observers are consistent with black holes as unitary quantum systems, with density of states given by the Bekenstein-Hawking formula. However, this comes at the cost of superselection sectors associated with the state of baby universes. Spacetimes studied by Polchinski and Strominger in 1994 provide a simple illustration of the associated concepts and techniques, and we argue them to be a natural late-time extrapolation of replica wormholes. The work aims to be self-contained and, in particular, to be accessible to readers who have not yet mastered earlier formulations of the ideas above.

scholarly journals On mean curvature flow of spacelike hypersurfaces in asymptotically flat spacetimes

1993 ◽  
Vol 55 (1) ◽  
pp. 41-59 ◽  
Author(s):  
Klaus Ecker
Keyword(s):  
Mean Curvature ◽  
Mean Curvature Flow ◽  
A Priori Estimates ◽  
A Priori ◽  
Curvature Flow ◽  
Lorentzian Manifold ◽  
Asymptotically Flat ◽  
Spacelike Hypersurfaces ◽  
Flat Spacetimes ◽  
Weaker Conditions

AbstractWe prove a priori estimates for the gradient and curvature of spacelike hypersurfaces moving by mean curvature in a Lorentzian manifold. These estimates are obtained under much weaker conditions than have been previously assumed. We also use mean curvature flow in the construction of maximal slices in asymptotically flat spacetimes. An essential tool is a maximum principle for sub-solutions of a parabolic operator on complete Riemannian manifolds with time-dependent metric.

scholarly journals Soft Factor In the Implementation of Quality Management Program in Majlis Agama Islam Selangor (MAIS)

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Musaiyadah Ahmadun ◽  
Siti Arni Basir ◽  
Osman Md Rasip
Keyword(s):  
Quality Management ◽  
Qualitative Method ◽  
Training And Development ◽  
Management Program ◽  
Depth Information ◽  
Soft Or ◽  
Structured Interviews ◽  
Soft Factor ◽  
Soft Factors

Many studies on the implementation of quality management programs were carried out by previous researchers. However, the study on the soft or human factors in the implementation of quality management programs is still poorly explored. Therefore, this article aims to analyze soft factors in the implementation of quality management programs at Selangor Islamic Religious Council or Majlis Agama Islam Selangor (MAIS). This study uses a qualitative method involving MAIS as a case study. Semi-structured interviews were used as a data collection method and supported by relevant documents collected from MAIS. A total of fifteen informants comprising top management and MAIS officers were interviewed to obtain in-depth information on the subjects studied. The findings reveal that there are six soft factors emerged in the implementation of quality management programs at MAIS namely leadership, training and development, teamwork, customer focus, Syura and rewards. This study demonstrates that soft factors has helped facilitate the implementation of quality management programs in MAIS. The results of this study can be used as guidance by managers in public or corporate organizatons in their efforts to implement quality management programs effectively.

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