20,583 research outputs found
The Bragg regime of the two-particle Kapitza-Dirac effect
We analyze the Bragg regime of the two-particle Kapitza-Dirac arrangement,
completing the basic theory of this effect. We provide a detailed evaluation of
the detection probabilities for multi-mode states, showing that a complete
description must include the interaction time in addition to the usual
dimensionless parameter w. The arrangement can be used as a massive
two-particle beam splitter. In this respect, we present a comparison with
Hong-Ou-Mandel-type experiments in quantum optics. The analysis reveals the
presence of dips for massive bosons and a differentiated behavior of
distinguishable and identical particles in an unexplored scenario. We suggest
that the arrangement can provide the basis for symmetrization verification
schemes
Trace elements accumulation in the sea lamprey along the major hydrographic basins of Portugal
Trace elements accumulation in the sea lamprey along the major hydrographic basins of Portuga
A new proof of the Herman-Avila-Bochi formula for Lyapunov exponents of SL(2,R)-cocycles
We study the geometry of the action of SL(2,R) on the projective line in
order to present a new and simpler proof of the Herman-Avila-Bochi formula.
This formula gives the average Lyapunov exponent of a class of 1-families of
SL(2,R)-cocycles.Comment: 13 pages, 2 figure
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Optical interferometry- from astronomy to art
After more than a century, Michelson’s interferometer is still at the forefront of scientific investigation. While the first application was in astronomy, it is now used as a novel technique in a wide range of subjects, notably in the form of Optical Coherence Tomography used primarily for biomedical applications. This paper will introduce a new application of the interferometer for the examination of art for conservation purposes
Precise analysis of pion-pion scattering data from Roy equations and forward dispersion relations
We review our recent analysis of pion-pion scattering data in terms of Roy
equations and Forward Dispersion Relations, and present some preliminary
results in terms of a new set of once-subtracted coupled equations for partial
waves. The first analysis consists of independent fits to the different
pion-pion channels that satisfies rather well the dispersive representation. In
the second analysis we constrain the fit with the dispersion relations. The
latter provides a very precise and model independent description of data using
just analyticity, causality and crossing.Comment: 6 pages, two figures. To appear in the proceedings of the Workshop on
Scalar Mesons and Related Topics, Lisbon, Portugal, 11-16 Feb 200
Gravitational waves from the Papaloizou-Pringle instability in black hole-torus systems
Black hole (BH)--torus systems are promising candidates for the central
engine of gamma-ray bursts (GRBs), and also possible outcomes of the collapse
of supermassive stars to supermassive black holes (SMBHs). By three-dimensional
general relativistic numerical simulations, we show that an
nonaxisymmetric instability grows for a wide range of self-gravitating tori
orbiting BHs. The resulting nonaxisymmetric structure persists for a timescale
much longer than the dynamical one, becoming a strong emitter of large
amplitude, quasiperiodic gravitational waves. Our results indicate that both,
the central engine of GRBs and newly formed SMBHs, can be strong gravitational
wave sources observable by forthcoming ground-based and spacecraft detectors.Comment: 4 pages, 4 figure, to be published in PR
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