1,385 research outputs found
Inflation Driven by Unification Energy
We examine the hypothesis that inflation is primarily driven by vacuum energy
at a scale indicated by gauge coupling unification. Concretely, we consider a
class of hybrid inflation models wherein the vacuum energy associated with a
grand unified theory condensate provides the dominant energy during inflation,
while a second "inflaton" scalar slow-rolls. We show that it is possible to
obtain significant tensor-to-scalar ratios while fitting the observed spectral
index.Comment: 5 double column pages, 1 figure. V2: Updated to resemble version
published in PR
Anyonic Realization of the Quantum Affine Lie Algebra U_q(A_N)
We give a realization of quantum affine Lie algebra in
terms of anyons defined on a two-dimensional lattice, the deformation parameter
being related to the statistical parameter of the anyons by . In the limit of the deformation parameter going to one we recover
the Feingold-Frenkel fermionic construction of undeformed affine Lie algebra.Comment: 13p LaTeX Document (should be run twice
Some Calculable Contributions to Entanglement Entropy
Entanglement entropy appears as a central property of quantum systems in
broad areas of physics. However, its precise value is often sensitive to
unknown microphysics, rendering it incalculable. By considering parametric
dependence on correlation length, we extract finite, calculable contributions
to the entanglement entropy for a scalar field between the interior and
exterior of a spatial domain of arbitrary shape. The leading term is
proportional to the area of the dividing boundary; we also extract finite
subleading contributions for a field defined in the bulk interior of a
waveguide in 3+1 dimensions, including terms proportional to the waveguide's
cross-sectional geometry; its area, perimeter length, and integrated curvature.
We also consider related quantities at criticality and suggest a class of
systems for which these contributions might be measurable.Comment: 4+ pages, 1 figure. v2: Some clarifications and more references;
updated to resemble version published in PR
Model study of the sign problem in the mean-field approximation
We argue the sign problem of the fermion determinant at finite density. It is
unavoidable not only in Monte-Carlo simulations on the lattice but in the
mean-field approximation as well. A simple model deriving from Quantum
Chromodynamics (QCD) in the double limit of large quark mass and large quark
chemical potential exemplifies how the sign problem arises in the Polyakov loop
dynamics at finite temperature and density. In the color SU(2) case our
mean-field estimate is in excellent agreement with the lattice simulation. We
combine the mean-field approximation with a simple phase reweighting technique
to circumvent the complex action encountered in the color SU(3) case. We also
investigate the mean-field free energy, from the saddle-point of which we can
estimate the expectation value of the Polyakov loop.Comment: 14 page, 18 figures, typos corrected, references added, some
clarification in sec.I
Gravitational Correction to Running of Gauge Couplings
We calculate the contribution of graviton exchange to the running of gauge
couplings at lowest non-trivial order in perturbation theory. Including this
contribution in a theory that features coupling constant unification does not
upset this unification, but rather shifts the unification scale. When
extrapolated formally, the gravitational correction renders all gauge couplings
asymptotically free.Comment: 4 pages, 2 figures; v2: Clarified awkward sentences and notations.
Corrected typos. Added references and discussion thereof in introduction.
Minor copy editting changes to agree with version to be published in Physical
Review Letter
On the Electromagnetic Interactions of Anyons
Using the appropriate representation of the Poincare group and a definition
of minimal coupling, we discuss some aspects of the electromagnetic
interactions of charged anyons. In a nonrelativistic expansion, we derive a
Schrodinger-type equation for the anyon wave function which includes
spin-magnetic field and spin-orbit couplings. In particular, the gyromagnetic
ratio for charged anyons is shown to be 2; this last result is essentially a
reflection of the fact that the spin is parallel to the momentum in (2+1)
dimensions.Comment: 13 pages, RU-92-17-B,CU-TP-584, CERN-TH6768/9
Electroweak symmetry breaking and cold dark matter from strongly interacting hidden sector
We consider a hidden sector with a vectorlike confining gauge theory like QCD
with colors and light quarks in the hidden
sector. Then a scale would be generated by dimensional
transmutation, and chiral symmetry breaking occurs in the hidden sector. This
scale can play a role of the SM Higgs mass parameter, triggering
electroweak symmetry breaking (EWSB). Furthermore the lightest mesons in the
hidden sector is stable by flavor conservation of the hidden sector strong
interaction, and could be a good cold dark matter (CDM). We study collider
phenomenology, and relic density and direct detection rates of the CDM of this
model.Comment: The version which appeared in Phys. Lett.
Equation of State in a Strongly Interacting Relativistic System
We study the evolution of the equation of state of a strongly interacting
quark system as a function of the diquark interaction strength. We show that
for the system to avoid collapsing into a pressureless Boson gas at
sufficiently strong diquark coupling strength, the diquark-diquark repulsion
has to be self-consistently taken into account. In particular, we find that the
tendency at zero temperature of the strongly interacting diquark gas to
condense into the system ground state is compensated by the repulsion between
diquarks if the diquark-diquark coupling constant is higher than a critical
value . Considering such diquark-diquark repulsion, a positive
pressure with no significant variation along the whole strongly interacting
region is obtained. A consequence of the diquark-diquark repulsion is that the
system maintains its BCS character in the whole strongly interacting region.Comment: 9 pages, 7 figs, To appear in Phys. Rev.
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