8 research outputs found
Effective source approach to self-force calculations
Numerical evaluation of the self-force on a point particle is made difficult
by the use of delta functions as sources. Recent methods for self-force
calculations avoid delta functions altogether, using instead a finite and
extended "effective source" for a point particle. We provide a review of the
general principles underlying this strategy, using the specific example of a
scalar point charge moving in a black hole spacetime. We also report on two new
developments: (i) the construction and evaluation of an effective source for a
scalar charge moving along a generic orbit of an arbitrary spacetime, and (ii)
the successful implementation of hyperboloidal slicing that significantly
improves on previous treatments of boundary conditions used for
effective-source-based self-force calculations. Finally, we identify some of
the key issues related to the effective source approach that will need to be
addressed by future work.Comment: Invited review for NRDA/Capra 2010 (Theory Meets Data Analysis at
Comparable and Extreme Mass Ratios), Perimeter Institute, June 2010, CQG
special issue - 22 pages, 8 figure
Quantization of fermions on Kerr space-time
We study a quantum fermion field on a background nonextremal Kerr black hole. We discuss the definition of the standard black hole quantum states (Boulware, Unruh, and Hartle-Hawking), focussing particularly on the differences between fermionic and bosonic quantum field theory. Since all fermion modes (both particle and antiparticle) have positive norm, there is much greater flexibility in how quantum states are defined compared with the bosonic case. In particular, we are able to define a candidate Boulware-like state, empty at both past and future null infinity, and a candidate Hartle-Hawking-like equilibrium state, representing a thermal bath of fermions surrounding the black hole. Neither of these states have analogues for bosons on a nonextremal Kerr black hole and both have physically attractive regularity properties. We also define a number of other quantum states, numerically compute differences in expectation values of the fermion current and stress-energy tensor between two states, and discuss their physical properties
Black hole determinants and quasinormal modes
We derive an expression for functional determinants in thermal spacetimes as
a product over the corresponding quasinormal modes. As simple applications we
give efficient computations of scalar determinants in thermal AdS, BTZ black
hole and de Sitter spacetimes. We emphasize the conceptual utility of our
formula for discussing `1/N' corrections to strongly coupled field theories via
the holographic correspondence.Comment: 28 pages. v2: slightly improved exposition, references adde
Self-force: Computational Strategies
Building on substantial foundational progress in understanding the effect of
a small body's self-field on its own motion, the past 15 years has seen the
emergence of several strategies for explicitly computing self-field corrections
to the equations of motion of a small, point-like charge. These approaches
broadly fall into three categories: (i) mode-sum regularization, (ii) effective
source approaches and (iii) worldline convolution methods. This paper reviews
the various approaches and gives details of how each one is implemented in
practice, highlighting some of the key features in each case.Comment: Synchronized with final published version. Review to appear in
"Equations of Motion in Relativistic Gravity", published as part of the
Springer "Fundamental Theories of Physics" series. D. Puetzfeld et al.
(eds.), Equations of Motion in Relativistic Gravity, Fundamental Theories of
Physics 179, Springer, 201