29,832 research outputs found
On the possibility of an astronomical detection of chromaticity effects in microlensing by wormhole-like objects
We study the colour changes induced by blending in a wormhole-like
microlensing scenario with extended sources. The results are compared with
those obtained for limb darkening. We assess the possibility of an actual
detection of the colour curve using the difference image analysis method.Comment: Accepted for publication in Modern Physics Letters A. 13 report
pages, 7 figure
Radiation effects on the electronic structure of bilayer graphene
We report on the effects of laser illumination on the electronic properties
of bilayer graphene. By using Floquet theory combined with Green's functions we
unveil the appeareance of laser-induced gaps not only at integer multiples of
but also at the Dirac point with features which are shown to
depend strongly on the laser polarization. Trigonal warping corrections are
shown to lead to important corrections for radiation in the THz range, reducing
the size of the dynamical gaps. Furthermore, our analysis of the topological
properties at low energies reveals that when irradiated with linearly polarized
light, ideal bilayer graphene behaves as a trivial insulator, whereas circular
polarization leads to a non-trivial insulator per valley.Comment: 5 pages 3 figure
Chromaticity effects in microlensing by wormholes
Chromaticity effects introduced by the finite source size in microlensing
events by presumed natural wormholes are studied. It is shown that these
effects provide a specific signature that allow to discriminate between
ordinary and negative mass lenses through the spectral analysis of the
microlensing events. Both galactic and extragalactic situations are discussed.Comment: To appear in Modern Physics Letters A, 200
Nonequilibrium many-body quantum dynamics: from full random matrices to real systems
We present an overview of our studies on the nonequilibrium dynamics of
quantum systems that have many interacting particles. Our emphasis is on
systems that show strong level repulsion, referred to as chaotic systems. We
discuss how full random matrices can guide and support our studies of realistic
systems. We show that features of the dynamics can be anticipated from a
detailed analysis of the spectrum and the structure of the initial state
projected onto the energy eigenbasis. On the other way round, if we only have
access to the dynamics, we can use it to infer the properties of the spectrum
of the system. Our focus is on the survival probability, but results for other
observables, such as the spin density imbalance and Shannon entropy are also
mentioned.Comment: 14 pages, 7 figures, chapter for the book "Thermodynamics in the
Quantum Regime - Recent Progress and Outlook
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