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Full-Text Articles in Physics

Renormalized Stress-Energy Tensor For Scalar Fields In Hartle-Hawking, Boulware, And Unruh States In The Reissner-Nordström Spacetime, Julio Arrechea, Cormac Breen, Adrian Ottewill, Peter Taylor Dec 2023

Renormalized Stress-Energy Tensor For Scalar Fields In Hartle-Hawking, Boulware, And Unruh States In The Reissner-Nordström Spacetime, Julio Arrechea, Cormac Breen, Adrian Ottewill, Peter Taylor

Articles

In this paper, we consider a quantum scalar field propagating on the Reissner-Nordström black hole spacetime. We compute the renormalized stress-energy tensor for the field in the Hartle-Hawking, Boulware and Unruh states. When the field is in the Hartle-Hawking state, we renormalize using the recently developed “extended coordinate” prescription. This method, which relies on Euclidean techniques, is very fast and accurate. Once, we have renormalized in the Hartle-Hawking state, we compute the stress-energy tensor in the Boulware and Unruh states by leveraging the fact that the difference between stress-energy tensors in different quantum states is already finite. We consider a …


A Mode-Sum Prescription For The Renormalized Stress Energy Tensor On Black Hole Spacetimes, Peter Taylor, Cormac Breen, Adrian Ottewill Sep 2022

A Mode-Sum Prescription For The Renormalized Stress Energy Tensor On Black Hole Spacetimes, Peter Taylor, Cormac Breen, Adrian Ottewill

Articles

In this paper, we describe an extremely efficient method for computing the renormalized stress-energy tensor of a quantum scalar field in spherically symmetric black hole spacetimes. The method applies to a scalar field with arbitrary field parameters. We demonstrate the utility of the method by computing the renormalized stress-energy tensor for a scalar field in the Schwarzschild black hole spacetime, applying our results to discuss the null energy condition and the semiclassical backreaction.


Mode-Sum Prescription For Vacuum Polarization In Black Hole Spacetimes In Even Dimensions, Peter Taylor, Cormac Doran Nov 2017

Mode-Sum Prescription For Vacuum Polarization In Black Hole Spacetimes In Even Dimensions, Peter Taylor, Cormac Doran

Articles

We present a mode-sum regularization prescription for computing the vacuum polarization of a scalar field in static spherically symmetric black hole spacetimes in even dimensions. This is the first general and systematic approach to regularized vacuum polarization in higher even dimensions, building upon a previous scheme we developed for odd dimensions. Things are more complicated here since the even-dimensional propagator possesses logarithmic singularities which must be regularized. However, in spite of this complication, the regularization parameters can be computed in closed form in arbitrary even dimensions and for arbitrary metric function f(r). As an explicit example of our method, we …


Mode-Sum Prescription For The Vacuum Polarization In Odd Dimensions, Peter Taylor, Cormac Breen Dec 2016

Mode-Sum Prescription For The Vacuum Polarization In Odd Dimensions, Peter Taylor, Cormac Breen

Articles

We present a new mode-sum regularization prescription for computing the vacuum polarization of a scalar field in static spherically-symmetric black hole spacetimes in odd dimensions. This is the first general and systematic approach to regularized vacuum polarization in higher dimensions. Remarkably, the regularization parameters can be computed in closed form in arbitrary dimensions and for arbitrary metric function $f(r)$. In fact, we show that in spite of the increasing severity and number of the divergences to be regularized, the method presented is mostly agnostic to the number of dimensions. Finally, as an explicit example of our method, we show plots …


Creating A Uniform Magnetic Field For The Equi-Biaxial Physical Testing Of Magnetorheological Elastomers; Electromagnet Design, Development And Testing., Dave Gorman, Stephen Jerrams, Ray Ekins, Niall Murphy Sep 2011

Creating A Uniform Magnetic Field For The Equi-Biaxial Physical Testing Of Magnetorheological Elastomers; Electromagnet Design, Development And Testing., Dave Gorman, Stephen Jerrams, Ray Ekins, Niall Murphy

Conference Papers

No abstract provided.


A Suggested Building Block Geometry Without Continuous Radial Joints Of Possible Relevance For Particle Detectors, Jim Mcgovern Jul 2010

A Suggested Building Block Geometry Without Continuous Radial Joints Of Possible Relevance For Particle Detectors, Jim Mcgovern

Articles

A geometry for concentrc shells or tubes, built-up from a single rhombohedral block type, is described. Continuous radial joints are avoided.


An Approach To Unification Using A Linear Systems Model For The Propagation Of Broad-Band Signals, Jonathan Blackledge Jan 2007

An Approach To Unification Using A Linear Systems Model For The Propagation Of Broad-Band Signals, Jonathan Blackledge

Articles

We review the inhomogeneous scalar Helmholtz equation in three-dimensions and the scattering of scalar wavefields from a scatterer of compact support. An asymptotic solution is then considered representing the effect of the frequency approaching zero when a ‘wavefield’ reduces to a ‘field’. The characteristics of ultra-low frequency Helmholtz scattering are then considered and the physical significance discussed of a model that is based on the scattering of Helmholtz wavefields over a broad frequency spectrum. This is equivalent to using a linear systems approach for modelling the propagation, interaction and detection of broad-band signals and provides an approach to the classification …


Generalized Moonshine And Orbifold Constructions, Michael Tuite, Rossen Ivanov Jan 2002

Generalized Moonshine And Orbifold Constructions, Michael Tuite, Rossen Ivanov

Conference papers

A brief review is given of some of our recent work on Generalised Monstrous Moonshine using abelian orbifoldings of the Moonshine Module.


Some Irrational Generalised Moonshine From Orbifolds, Rossen Ivanov, Michael Tuite Jan 2002

Some Irrational Generalised Moonshine From Orbifolds, Rossen Ivanov, Michael Tuite

Articles

We verify the Generalised Moonshine conjectures for some irrational modular functions for theMonster centralisers related to the Harada-Norton, Held, M12 and L3(3) simple groups based on certain orbifolding constraints. We find explicitly the fixing groups of the hauptmoduls arising in each case.


Rational Generalized Moonshine From Abelian Orbifoldings Of The Moonshine Module, Rossen Ivanov, Michael Tuite Jan 2002

Rational Generalized Moonshine From Abelian Orbifoldings Of The Moonshine Module, Rossen Ivanov, Michael Tuite

Articles

We consider orbifoldings of the Moonshine Module with respect to the abelian group generated by a pair of commuting Monster group elements with one of prime order p = 2, 3, 5, 7 and the other of order pk for k = 1 or k prime. We show that constraints arising from meromorphic orbifold conformal field theory allow us to demonstrate that each orbifold partition function with rational coefficients is either constant or is a hauptmodul for an explicitly found modular fixing group of genus zero. We thus confirm in the cases considered the Generalised Moonshine conjectures for all rational …


Rational Generalised Moonshine From Orbifolds, Rossen Ivanov, Michael Tuite Jan 2000

Rational Generalised Moonshine From Orbifolds, Rossen Ivanov, Michael Tuite

Articles

Frenkel, Lepowsky and Meurman constructed the Moonshine Module (MM) as a Z2 orbifold of the Leech Lattice Meromorphic Conformal field theory. The group of automorphisms of this theory is the 'Monster Group' M - the largest finite sporadic simple group (with order ~ 8. 1053 ). 'Monstrous Moonshine' is the famous observation that the Thompson series, corresponding to each class of M, is a hauptmodule for some genus zero fixing group. Norton considered Generalised Moonshine Functions (GMF), depending on two commuting Monster elements, and suggested that they are also hauptmodules. Using meromorphid Abelian orbifoldings of MM we identify …