158 research outputs found
Einstein-Dirac-Maxwell wormholes in quantum field theory
Charged Dirac fields minimally coupled to gravity have spherically symmetric
wormhole solutions known as Einstein-Dirac-Maxwell (EDM) wormholes. EDM
wormholes do not make use of exotic matter and exist in asymptotically flat
general relativity. We construct static spherically symmetric EDM wormhole
configurations in quantum field theory using semiclassical approximations for
gravity and the electromagnetic field. Our framework is able to describe a
broader class of EDM wormholes than previously considered and, being
constructed in quantum field theory, puts EDM wormholes on firmer theoretical
ground.Comment: 12 pages, 5 figures; v2: typos correcte
Einstein-Dirac in semiclassical gravity
We study the Dirac equation minimally coupled to general relativity using
quantum field theory and the semiclassical gravity approximation. Previous
studies of the Einstein-Dirac system did not quantize the Dirac field and
required multiple independent Dirac fields to preserve spherical symmetry. We
canonically quantize a single Dirac field in a static spherically symmetric
curved spacetime background. Using the semiclassical gravity approximation, in
which the Einstein field equations are sourced by the expectation value of the
stress-energy-momentum tensor, we derive a system of equations whose solutions
describe static spherically symmetric self-gravitating configurations of
identical quantum spin-1/2 particles. We self-consistently solve these
equations and present example configurations. Although limiting cases of our
semiclassical system of equations reproduce the multi-field system of equations
found in the literature, our system of equations is derived from the
excitations of a single quantum field.Comment: 17 pages, 2 figure
Retrofitting Models of Inflation
I use the method of retrofitting, developed by Dine, Feng and Silverstein, to
generate the scale of inflation dynamically, allowing it to be naturally small.
This is a general procedure that may be performed on existing models of
supersymmetric inflation. I illustrate this idea on two such models, one an
example of F-term inflation and the other an example of D-term inflation.Comment: 11 page
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