Title:	Spherical collapse and black hole evaporation
Authors:	Varadarajan, Madhavan
Keywords:	genaral relativity quantum aspects of black holes quantum fields in curved spacetime
Issue Date:	8-Jan-2025
Publisher:	American Physical Society
Citation:	Physical Review D, 2025, Vol. 111, p026005
Abstract:	We consider spherically symmetric gravity coupled to a spherically symmetric scalar field with a specific coupling which depends on the areal radius. Appropriate to spherical collapse, we require the existence of an axis of symmetry and consequently a single asymptotic past and future (rather than a pair of “left” and “right” ones). The scalar field stress energy takes the form of null dust. Its classical collapse is described by the Vaidya solution. From a two dimensional “(𝑟,𝑡)” perspective, the scalar field is conformally coupled so that its quantum stress energy expectation value is well defined. Quantum backreaction is then incorporated through an explicit formulation of the 4D semiclassical Einstein equations. The semiclassical solution describes black hole formation together with its subsequent evaporation along a timelike dynamical horizon (i.e. a timelike outer marginally trapped “tube”). A balance law at future null infinity relates the rate of change of a backreaction-corrected Bondi mass to a manifestly positive flux. The detailed form of this balance law together with a proposal for the dynamics of the true degrees of freedom underlying the putative nonperturbative quantum gravity theory is supportive of the paradigm of singularity resolution and information recovery proposed by Ashtekar and Bojowald. In particular all the information including that in the collapsing matter is expected, in our proposed scenario, to emerge along a single “quantum extended” future null infinity. Our analysis is on the one hand supported and informed by earlier numerical work of Lowe [Phys. Rev. D 47, 2446 (1993)] and Parentani and Piran [Phys. Rev. Lett. 73, 2805 (1994)] and on the other, serves to clarify certain aspects of their work through our explicit requirement of the existence of an axis of symmetry.
Description:	Open Access
URI:	http://hdl.handle.net/2289/8376
Alternative Location:	https://arxiv.org/abs/2406.09176 https://doi.org/10.1103/PhysRevD.111.026005 https://ui.adsabs.harvard.edu/abs/2025PhRvD.111b6005V/abstract https://inspirehep.net/literature/2797762
Copyright:	2025 American Physical Society
Appears in Collections:	Research Papers (TP)

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