388 research outputs found
Exact metric around a wiggly cosmic string
The exact metric around a wiggly cosmic string is found by modifying the
energy momentum-tensor of a straight infinitely thin cosmic string to include
an electric current along the symmetry axis.Comment: 5 page
Anomaly/Transport in an Ideal Weyl gas
We study some of the transport processes which are specific to an ideal gas
of relativistic Weyl fermions and relate the corresponding transport
coefficients to various anomaly coefficients of the system. We propose that
these transport processes can be thought of as arising from the continuous
injection of chiral states and their subsequent adiabatic flow driven by
vorticity. This in turn leads to an elegant expression relating the anomaly
induced transport coefficients to the anomaly polynomial of the Ideal Weyl gas.Comment: 35 pages, JHEP forma
Fractional Super Lie Algebras and Groups
n^{th} root of a Lie algebra and its dual (that is fractional supergroup)
based on the permutation group invariant forms are formulated in the Hopf
algebra formalism. Detailed discussion of -graided algebras is
done.Comment: 13 pages, detailed discussion of -graided is adde
Membranes in the two-Higgs standard model
We present some non-topological static wall solutions in two-Higgs extensions
of the standard model. They are classically stable in a large region of
parameter space, compatible with perturbative unitarity and with present
phenomenological bounds.Comment: 7 pages, latex, 3 figures available upon reques
Cosmic Strings Lens Phenomenology: Model of Poisson Energy Distribution
We present a novel approach for investigating lens phenomenology of cosmic
strings in order to elaborate detection strategies in galaxy deep field images.
To account for the complexity of the projected energy distribution of string
networks we assume their lens effects to be similar to those of a straight
string carrying a {\em random} lineic energy distribution. In such a model we
show that, unlike the case of uniform strings, critical phenomena naturally
appear. We explore the properties of the critical lines and caustics. In
particular, assuming that the energy coherence length along the string is much
smaller than the observation scale, we succeeded in computing the total length
of critical lines per unit string length and found it to be . The length of the associated caustic lines can also be computed to be
. The picture we obtain here for the
phenomenology of cosmic string detection is clearly at variance with common
lore.Comment: 10 pages, 5 figures. Minor correction
Chiral Heat Wave and mixing of Magnetic, Vortical and Heat waves in chiral media
We show that a hot rotating fluid of relativistic chiral fermions possesses a
new gapless collective mode associated with coherent propagation of energy
density and chiral density waves along the axis of rotation. This mode, which
we call the Chiral Heat Wave, emerges due to a mixed gauge-gravitational
anomaly. At finite density the Chiral Heat Wave couples to the Chiral Vortical
Wave while in the presence of an external magnetic field it mixes with the
Chiral Magnetic Wave. The coupling of the Chiral Magnetic and Chiral Vortical
Waves is also demonstrated. We find that the coupled waves - which are coherent
fluctuations of the vector, axial and energy currents - have generally
different velocities compared to the velocities of the individual waves.Comment: 33 pages, 6 figures; v2: minor changes, published versio
Evolution Equation for Generalized Parton Distributions
The extension of the method [arXiv:hep-ph/0503109] for solving the leading
order evolution equation for Generalized Parton Distributions (GPDs) is
presented. We obtain the solution of the evolution equation both for the flavor
nonsinglet quark GPD and singlet quark and gluon GPDs. The properties of the
solution and, in particular, the asymptotic form of GPDs in the small x and \xi
region are discussed.Comment: REVTeX4, 34 pages, 3 figure
Cosmological Measures without Volume Weighting
Many cosmologists (myself included) have advocated volume weighting for the
cosmological measure problem, weighting spatial hypersurfaces by their volume.
However, this often leads to the Boltzmann brain problem, that almost all
observations would be by momentary Boltzmann brains that arise very briefly as
quantum fluctuations in the late universe when it has expanded to a huge size,
so that our observations (too ordered for Boltzmann brains) would be highly
atypical and unlikely. Here it is suggested that volume weighting may be a
mistake. Volume averaging is advocated as an alternative. One consequence may
be a loss of the argument that eternal inflation gives a nonzero probability
that our universe now has infinite volume.Comment: 15 pages, LaTeX, added references for constant-H hypersurfaces and
also an idea for minimal-flux hypersurface
Dynamics of Gravitating Magnetic Monopoles
According to previous work on magnetic monopoles, static regular solutions
are nonexistent if the vacuum expectation value of the Higgs field is
larger than a critical value , which is of the order of the
Planck mass. In order to understand the properties of monopoles for
, we investigate their dynamics numerically. If is
large enough (), a monopole expands exponentially and a
wormhole structure appears around it, regardless of coupling constants and
initial configuration. If is around , there are three
types of solutions, depending on coupling constants and initial configuration:
a monopole either expands as stated above, collapses into a black hole, or
comes to take a stable configuration.Comment: 11 pages, revtex, postscript figures; results for various initial
conditions are added; to appear in Phys. Rev.
The no-boundary measure in string theory: Applications to moduli stabilization, flux compactification, and cosmic landscape
We investigate the no-boundary measure in the context of moduli
stabilization. To this end, we first show that for exponential potentials,
there are no classical histories once the slope exceeds a critical value. We
also investigate the probability distributions given by the no-boundary wave
function near maxima of the potential. These results are then applied to a
simple model that compactifies 6D to 4D (HBSV model) with fluxes. We find that
the no-boundary wave function effectively stabilizes the moduli of the model.
Moreover, we find the a priori probability for the cosmological constant in
this model. We find that a negative value is preferred, and a vanishing
cosmological constant is not distinguished by the probability measure. We also
discuss the application to the cosmic landscape. Our preliminary arguments
indicate that the probability of obtaining anti de Sitter space is vastly
greater than for de Sitter.Comment: 27 pages, 8 figure
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