953 research outputs found
Properties of Odd Gap Superconductors
A new class of superconductors with the gap function {\it odd} under time
reversal is considered. Some of the physical properties of these
superconductors such as the Meissner effect, composite condensate, gapless
spectrum and transition from the {\it odd} gap superconductor to the BCS state
at lower temperatures are discussed.Comment: 9 pages + 2 fig, LA-UR-93-299
Response of SBDs to MeV protons, tritons and alphas: evidence that the charged particle sensitive depth is not generally the depletion layer depth
Super black hole as spinning particle: Supersymmetric baglike core
We consider particlelike solutions to supergravity based on the Kerr-Newman
black hole (BH) solution. The BH singularity is regularized by means of a phase
transition to a new vacuum state near the core region confining a dual gauge
field. Supersymmetric BPS-saturated domain wall model is suggested which can
provide this phase transition and formation the stable charged superconducting
core. For spinning particle the core takes the form of thin, relativistically
rotaiting disk.Comment: 9 pages, Latex, plenary talks given at the School-Workshop
Praha-Spin-2001 (Prague,July 15-28,2001) and at the XXIV International
Workshop on Fundamental Problems of HEP and Field Theory (IHEP, June 2001,
Protvino
On the effective potential for Horava-Lifshitz-like theories with the arbitrary critical exponent
We calculate the one-loop effective potential for Horava-Lifshitz-like QED
and Yukawa-like theory for arbitrary values of the critical exponent and the
space-time dimension.Comment: 10 pages, version accepted in PL
Probing the Planck Scale with Neutrino Oscillations
Quantum gravity "foam", among its various generic Lorentz non-invariant
effects, would cause neutrino mixing. It is shown here that, if the foam is
manifested as a nonrenormalizable effect at scale M, the oscillation length
generically decreases with energy as (E/M)^(-2). Neutrino observatories and
long-baseline experiments should have therefore already observed foam-induced
oscillations, even if M is as high as the Planck energy scale. The null
results, which can be further strengthened by better analysis of current data
and future experiments, can be taken as experimental evidence that Lorentz
invariance is fully preserved at the Planck scale, as is the case in critical
string theory.Comment: 11 pages, 2 figures. Final version published in PRD. 1 figure,
references, clarifications and explanations added. Results unchange
Decoherence and CPT Violation in a Stringy Model of Space-Time Foam
I discuss a model inspired from the string/brane framework, in which our
Universe is represented as a three brane, propagating in a bulk space time
punctured by D0-brane (D-particle) defects. As the D3-brane world moves in the
bulk, the D-particles cross it, and from an effective observer on D3 the
situation looks like a ``space-time foam'' with the defects ``flashing'' on and
off (``D-particle foam''). The open strings, with their ends attached on the
brane, which represent matter in this scenario, can interact with the
D-particles on the D3-brane universe in a topologically non-trivial manner,
involving splitting and capture of the strings by the D0-brane defects. Such
processes are described by logarithmic conformal field theories on the
world-sheet. Physically, they result in effective decoherence of the string
matter on the D3 brane, and as a result, of CPT Violation, but of a type that
implies an ill-defined nature of the effective CPT operator. Due to electric
charge conservation, only electrically neutral (string) matter can exhibit such
interactions with the D-particle foam. This may have unique, experimentally
detectable, consequences for electrically-neutral entangled quantum matter
states on the brane world, in particular the modification of the pertinent EPR
Correlation of neutral mesons in a meson factory.Comment: 41 pages Latex, five eps figures incorporated. Uses special macro
Standard Model Higgs boson mass from inflation: two loop analysis
We extend the analysis of \cite{Bezrukov:2008ej} of the Standard Model Higgs
inflation accounting for two-loop radiative corrections to the effective
potential. As was expected, higher loop effects result in some modification of
the interval for allowed Higgs masses m_min<m_H<m_max, which somewhat exceeds
the region in which the Standard Model can be considered as a viable effective
field theory all the way up to the Planck scale. The dependence of the index
n_s of scalar perturbations on the Higgs mass is computed in two different
renormalization procedures, associated with the Einstein (I) and Jordan (II)
frames. In the procedure I the predictions of the spectral index of scalar
fluctuations and of the tensor-to-scalar ratio practically do not depend on the
Higgs mass within the admitted region and are equal to n_s=0.97 and r=0.0034
respectively. In the procedure II the index n_s acquires the visible dependence
on the Higgs mass and and goes out of the admitted interval at m_H below m_min.
We compare our findings with the results of \cite{DeSimone:2008ei}.Comment: 24 paged, 9 figures. Journal version (typos fixed, expanded
discussions
Detection Limits for Super-Hubble Suppression of Causal Fluctuations
We investigate to what extent future microwave background experiments might
be able to detect a suppression of fluctuation power on large scales in flat
and open universe models. Such suppression would arise if fluctuations are
generated by causal processes, and a measurement of a small suppression scale
would be problematic for inflation models, but consistent with many defect
models. More speculatively, a measurement of a suppression scale of the order
of the present Hubble radius could provide independent evidence for a
fine-tuned inflation model leading to a low-density universe. We find that,
depending on the primordial power spectrum, a suppression scale modestly larger
than the visible Horizon can be detected, but that the detectability drops very
rapidly with increasing scale. For models with two periods of inflation, there
is essentially no possibility of detecting a causal suppression scale.Comment: 8 pages, 4 figures, revtex, In Press Physical Review D 200
Observers in an accelerated universe
If the current acceleration of our Universe is due to a cosmological
constant, then a Coleman-De Luccia bubble will nucleate in our Universe. In
this work, we consider that our observations could be likely in this framework,
consisting in two infinite spaces, if a foliation by constant mean curvature
hypersurfaces is taken to count the events in the spacetime. Thus, we obtain
and study a particular foliation, which covers the existence of most observers
in our part of spacetime.Comment: revised version, accepted in EPJ
The ambiguity-free four-dimensional Lorentz-breaking Chern-Simons action
The four dimensional Lorentz-breaking finite and determined Chern-Simons like
action is generated as a one loop perturbative correction via an appropriate
Lorentz-breaking coupling of the gauge field with the spinor field. Unlike the
known schemes of calculations, within this scheme this term is found to be
regularization independent.Comment: Revtex4, 4 page
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