Vacuum polarization on topological black holes with Robin boundary conditions

Morley, Thomas; Winstanley, Elizabeth; Taylor, PM

doi:10.1103/physrevd.103.045007

Cited by 10 publications

(5 citation statements)

References 84 publications

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“…Previous work, [15][16][17]35] has indicated that boundary conditions play a very important role in whether or not anti-correlation effects are present. Moreover, other studies on the vacuum polarization [41,42] suggest that the Dirichlet boundary conditions on quantum fields in asymptotically AdS spacetimes are special in that the vacuum polarization asymptotes to the same value on the spacetime boundary in all Robin boundary conditions except for the Dirichlet case.…”

Section: Discussionmentioning

confidence: 99%

Response of an Unruh-DeWitt detector near an extremal black hole

Conroy,

Taylor

2021

Preprint

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We consider the response of an Unruh-DeWitt detector near an extremal charged black hole, modeling the near-horizon region of this extremal spacetime by the Bertotti-Robinson spacetime. The advantage of employing the Bertotti-Robinson limit is that the two-point functions for a massless scalar field are obtainable in closed form for the field in a number of quantum states of interest. We consider the detector coupled to a massless field in both the Boulware vacuum state and arbitrary thermal states, including the Hartle-Hawking state, and analyse the detector's response for a broad range of trajectories. Particular attention is paid to the thermalization of the detector, the anti-Unruh and anti-Hawking effect.

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Section: Discussionmentioning

confidence: 99%

Response of an Unruh-DeWitt detector near an extremal black hole

Conroy,

Taylor

2021

Preprint

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“…In this work, our approximations pertained to a scalar field satisfying Dirichlet boundary conditions at the timelike boundary of spatial infinity, but other boundary conditions are, of course, possible. In fact, the asymptotic values of the expectation values are generically not those produced by the Dirichlet boundary conditions [69,70], but instead all other Robin boundary conditions except the Dirichlet case asymptote to the same value. It would be interesting therefore to examine how strongly dependent is the backreaction on the choice of boundary condition.…”

Section: Discussionmentioning

confidence: 94%

Semiclassical backreaction on asymptotically anti–de Sitter black holes

Taylor

Breen

2021

Phys. Rev. D

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We consider a quantum scalar field on the classical background of an asymptotically anti-de Sitter black hole and the backreaction the field's stress-energy tensor induces on the black hole geometry. The backreaction is computed by solving the reduced-order semiclassical Einstein field equations sourced by simple analytical approximations for the renormalized expectation value of the scalar field stress-energy tensor. When the field is massless and conformally coupled, we adopt Page's approximation to the renormalized stress-energy tensor, while for massive fields we adopt a modified version of the DeWitt-Schwinger approximation. The latter approximation must be modified so that it possesses the correct renormalization freedom required to ensure the semiclassical equations are consistent. Equipped with these approximations, the reduced-order field equations are easily integrated and the first-order (in ℏ) corrections to the metric are obtained. We also compute the corrections to the black hole event horizon, surface gravity, and minimum temperature as well as corrections to the photon sphere and quadratic curvature invariants. We pay particular attention to the temperature profiles of the semiclassical black holes compared with their classical counterparts, pointing out some interesting qualitative features produced by the backreaction. These results ought to provide reasonable approximations to the first-order (one-loop) quantum backreaction on the geometry of asymptotically anti-de Sitter black holes when the exact numerical stressenergy tensor sources the semiclassical equations.

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“…At the same time, it is difficult to determine the concrete value of the nonuniform vacuum energy density because, according to (38), it contains an eikonal function Θ k , which is determined by the integral (36). For instance, one has Θ k (η, r) = q Θk,q (η)e iqr from ( 35), (36) and Θk,q (η) = 1 k…”

Section: Galactic Dm As a F -Vacuum Polarizationmentioning

confidence: 99%

“…The conventional renormalization procedure of the quantum field theory applied to vacuum energy near a massive object [31][32][33][34][35][36], leads to modification of the gravitational potential only at small distances of the order of gravitational radius that are unobservable with current technologies. That is, the renormalization excludes the manifestation of micro-scale phenomena on the macro-scales (nevertheless, see [20]).…”

Section: Introductionmentioning

confidence: 99%

Vacuum Polarization Instead of “Dark Matter” in a Galaxy

Cherkas

Калашников

2022

Universe

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We considered a vacuum polarization inside a galaxy in the eikonal approximation and found that two possible types of polarization exist. The first type is described by the equation of state p=ρ/3, similar to radiation. Using the conformally unimodular metric allows us to construct a non-singular solution for this vacuum “substance” if a compact astrophysical object exists in the galaxy’s center. As a result, a “dark” galactical halo appears that increases the rotation velocity of a test particle as a function of the distance from a galactic center. The second type of vacuum polarization has a more complicated equation of state. As a static physical effect, it produces the renormalization of the gravitational constant, thus, causing no static halo. However, a non-stationary polarization of the second type, resulting from an exponential increase (or decrease) of the galactic nuclei mass with time in some hypothetical time-dependent process, produces a gravitational potential, appearing similar to a dark matter halo.

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Vacuum polarization on topological black holes with Robin boundary conditions

Cited by 10 publications

References 84 publications

Response of an Unruh-DeWitt detector near an extremal black hole

Response of an Unruh-DeWitt detector near an extremal black hole

Semiclassical backreaction on asymptotically anti–de Sitter black holes

Vacuum Polarization Instead of “Dark Matter” in a Galaxy

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