3,513 research outputs found

### Energy Functions in Box Ball Systems

The box ball system is studied in the crystal theory formulation. New
conserved quantities and the phase shift of the soliton scattering are obtained
by considering the energy function (or $H$-function) in the combinatorial
$R$-matrix.Comment: 15 pages, LaTeX2e: one paragraph replaced and reference added in
Introduction, a paragraph added in Section 2.5, remark 2) after Th 4.6 adde

### Quantum Interference to Measure Spacetime Curvature: A Proposed Experiment at the Intersection of Quantum Mechanics and General Relativity

An experiment in Low Earth Orbit (LEO) is proposed to measure components of
the Riemann curvature tensor using atom interferometry. We show that the
difference in the quantum phase $\Delta\phi$ of an atom that can travel along
two intersecting geodesics is given by $mR_{0i0j}/\hbar$ times the spacetime
volume contained within the geodesics. Our expression for $\Delta\phi$ also
holds for gravitational waves in the long wavelength limit.Comment: 7 pages LaTeXed with RevTeX 4.0, 2 figures. Submitted to the 2003
Gravity Research Foundation Essay Contes

### Polar Perturbations of Self-gravitating Supermassive Global Monopoles

Spontaneous global symmetry breaking of O(3) scalar field gives rise to
point-like topological defects, global monopoles. By taking into account
self-gravity,the qualitative feature of the global monopole solutions depends
on the vacuum expectation value v of the scalar field. When v < sqrt{1 / 8 pi},
there are global monopole solutions which have a deficit solid angle defined at
infinity. When sqrt{1 / 8 pi} <= v < sqrt{3 / 8 pi}, there are global monopole
solutions with the cosmological horizon, which we call the supermassive global
monopole. When v >= sqrt{3 / 8 pi}, there is no nontrivial solution. It was
shown that all of these solutions are stable against the spherical
perturbations. In addition to the global monopole solutions, the de Sitter
solutions exist for any value of v. They are stable against the spherical
perturbations when v sqrt{3 / 8 pi}.
We study polar perturbations of these solutions and find that all
self-gravitating global monopoles are stable even against polar perturbations,
independently of the existence of the cosmological horizon, while the de Sitter
solutions are always unstable.Comment: 10 pages, 6 figures, corrected some type mistakes (already corrected
in PRD version

### Holographic storage of multiple coherence gratings in a Bose-Einstein condensate

We demonstrate superradiant conversion between a two-mode collective atomic
state and a single-mode light field in an elongated cloud of Bose-condensed
atoms. Two off-resonant write beams induce superradiant Raman scattering,
producing two independent coherence gratings with a different wave vector in
the cloud. By applying phase-matched read beams after a controllable delay, the
gratings can be selectively converted into the light field also in a
superradiant way. Due to the large cooperativity parameter and the small
velocity width of the condensate, a high conversion efficiency of $> 70$ % and
a long storage time of $> 120$ $\mu$s were achieved.Comment: 5 pages, 4 figure

### Observation of an energetic radiation burst from mountain-top thunderclouds

During thunderstorms on 2008 September 20, a simultaneous detection of gamma
rays and electrons was made at a mountain observatory in Japan located 2770 m
above sea level. Both emissions, lasting 90 seconds, were associated with
thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV,
can be interpreted as consisting of bremsstrahlung gamma rays arriving from a
source which is 60 - 130 m in distance at 90% confidence level. The observed
electrons are likely to be dominated by a primary population escaping from an
acceleration region in the clouds.Comment: 12 pages, 3 figures, accepted for publication in Physical Review
Letter

### Abelian Higgs Hair for AdS-Schwarzschild Black Hole

We show that the Abelian Higgs field equations in the background of the four
dimensional AdS-Schwarzschild black hole have a vortex line solution. This
solution, which has axial symmetry, is a generalization of the AdS spacetime
Nielsen-Olesen string. By a numerical study of the field equations, we show
that black hole could support the Abelian Higgs field as its Abelian hair.
Also, we conside the self gravity of the Abelian Higgs field both in the pure
AdS spacetime and AdS-Schwarzschild black hole background and show that the
effect of string as a black hole hair is to induce a deficit angle in the
AdS-Schwarzschild black hole.Comment: 19 pages, 33 figure

### Cosmic Colored Black Holes

We present spherically symmetric static solutions (a particle-like solution
and a black hole solution) in the Einstein-Yang-Mills system with a
cosmological constant.Although their gravitational structures are locally
similar to those of the Bartnik-McKinnon particles or the colored black holes,
the asymptotic behavior becomes quite different because of the existence of a
cosmological horizon. We also discuss their stability by means of a catastrophe
theory as well as a linear perturbation analysis and find the number of
unstable modes.Comment: 12 pages, latex, 4 figures (available upon request

### Looking for a charge asymmetry in cosmic rays

We combine the data from PAMELA and FERMI-LAT cosmic ray experiments by
introducing a simple sum rule. This allows to investigate whether the lepton
excess observed by these experiments is charge symmetric or not. We also show
how the data can be used to predict the positron fraction at energies yet to be
explored by the AMS-02 experiment.Comment: Contribution to the proceedings of DISCRETE 2010, 5 pages, 2 figure

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