515,937 research outputs found
A New Proof of the Faithfulness of Brauer's Representation of Temperley-Lieb Algebras
The faithfulness of the orthogonal group case of Brauer's representation of
the Brauer centralizer algebras restricted to their Temperley-Lieb subalgebras,
which was established by Vaughan Jones, is here proved in a new, elementary and
self-contained, manner.Comment: 10 pages, minor correction
Gamma-ray bursts: a Centauro's cry?
A new candidate for the gamma-ray bursts central engine is proposed: if in
some energetic cosmic event a macroscopic amount of bubbles of the disoriented
chiral condensate can be formed, then their subsequent decays will produce a
relativistic fireball without the baryon loading problem. The neutron star to
strange star transition is considered as a candidate example of such cosmic
event.Comment: 12 pages, LaTeX, somewhat modified, references adde
Thomas rotation and Mocanu paradox -- not at all paradoxical
Non-commutativity of the Einstein velocity addition, in case of non-collinear
velocities, seemingly gives rise to a conflict with reciprocity principle.
However, Thomas rotation comes at a rescue and the paradox is avoided. It is
shown that such a resolution of the so called Mocanu paradox is completely
natural from the point of view of basic premises of special relativity.Comment: 6 pages, 3 figures, revtex
Comment on the sums
This is a comment on the papers N. D. Elkies, Amer. Math. Monthly 110 (2003),
561-573 and Cvijovic and J. Klinowski, J. Comput. Appl. Math. 142 (2002),
435-439. We provide an explicit expression for the kernel of the integral
operator introduced in the first paper. This explicit expression considerably
simplifies the calculation of S(n) and enables a simple derivation of Cvijovic
and Klinowski's integral representation for .Comment: 11 pages, to be published in Georgian Mathematical Journal.
arXiv:1003.3602 is more extended version of this short not
Maxwell's demon through the looking glass
Mechanical Maxwell's demons, such as Smoluchowski's trapdoor and Feynman's
ratchet and pawl need external energy source to operate. If you cease to feed a
demon the Second Law of thermodynamics will quickly stop its operation.
Nevertheless, if the parity is an unbroken symmetry of nature, it may happen
that a small modification leads to demons which do not need feeding. Such
demons can act like perpetuum mobiles of the second kind: extract heat energy
from only one reservoir, use it to do work and be isolated from the rest of
ordinary world. Yet the Second Law is not violated because the demons pay their
entropy cost in the hidden (mirror) sector of the world by emitting mirror
photons.Comment: 28 pages, 3 figures, revtex
TeV scale gravity, mirror universe, and ... dinosaurs
This is somewhat extended version of the talk given at the Gran Sasso Summer
Institute: Massive Neutrinos in Physics and Astrophysics. It describes general
ideas about mirror world, extra spatial dimensions and dinosaur extinction.
Some suggestions are made how these seemingly different things can be related
to each other.Comment: 36 pages, 6 figures, presented at the Gran Sasso Summer Institute:
Massive Neutrinos in Physics and Astrophysics, 13-24 September, 1999. New
references added and some misprints corrected. To be published in Acta Phys.
Polonic
Pionium in the elementary particle decays
Some atomic decays of elementary particles with pionium
(-dimesoatom) in the final state are considered. Only for K-meson
atomic decays are the corresponding branching ratios big enough to make their
experimental study realistic. The order corrections to the lifetime
of pionium are also calculated.Comment: 12 pages, to appear in Pis'ma Zh. Eks. Teor. Fiz. 60(1994),67
Mirror dark matter discovered?
Recent astrophysical data indicates that dark matter shows a controversial
behaviour in galaxy cluster collisions. In case of the notorious Bullet
cluster, dark matter component of the cluster behaves like a collisionless
system. However, its behaviour in the Abell 520 cluster indicates a significant
self-interaction cross-section. It is hard for the WIMP based dark matter
models to reconcile such a diverse behaviour. Mirror dark matter models, on the
contrary, are more flexible and for them diverse behaviour of the dark matter
is a natural expectation.Comment: 13 pages, 5 figures, a typo correcte
Using the DIRBE/IRAS All-Sky Reddening Map To Select Low-Reddening Windows Near the Galactic Plane
Recently Schlegel, Finkbeiner & Davis published an all-sky reddening map
based on the COBE/DIRBE and IRAS/ISSA infrared sky surveys. Using the reddening
map of Baade's Window and sample of 19 low-latitude () Galactic
globular clusters I find that the DIRBE/IRAS reddening map overestimates
at low galactic latitudes by a factor of . I also
demonstrate the usefulness of this high resolution map for selecting
low-reddening windows near the Galactic plane.Comment: submitted to the ApJ Letters, 8 pages, 4 figure
Fermion Zero Modes and Cosmological Constant
A general condition for the existence of fermion zero modes is derived for
the M-5-brane, the M-2-brane and the D=4, N=2 Majumdar-Papapetrou 0-brane. The
fermion zero modes of these p-branes do not exist if the supersymmetry spinor
generator goes to a constant at the horizon and they exist only if it vanishes
there. In particular it is shown that the fermion zero mode of the M-2-brane in
D=11 can be forbidden from existence if Rarita-Schwinger gamma tracelessness
condition is imposed on the gravitino field. Non-existence of fermion zero mode
is interpreted, in analogy to the three dimensional example of Becker et.al.,
as a world with zero cosmological constant without supersymmetric excited
states. Also derived are the spin of the M-5-brane and its 3-form electric and
magnetic dipole moments.Comment: 11 pages of plain TeX. Harvmac
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