27,059 research outputs found
Effective interactions from q-deformed inspired transformations
From the mass term for the transformed quark fields, we obtain effective
contact interactions of the NJL type. The parameters of the model that maps a
system of non-interacting transformed fields into quarks interacting via NJL
contact terms are discussed
Charge migration mechanisms in the DNA at finite temperature revisited; from quasi-ballistic to subdiffusive transport
Various charge migration mechanisms in the DNA are studied within the
framework of the Peyrard-Bishop-Holstein model which has been widely used to
address charge dynamics in this macromolecule. To analyze these mechanisms we
consider characteristic size and time scales of the fluctuations of the
electronic and vibrational subsystems. It is shown, in particular, that due to
substantial differences in these timescales polaron formation is unlikely
within a broad range of temperatures. We demonstrate that at low temperatures
electronic transport can be quasi-ballistic. For high temperatures, we propose
an alternative to polaronic charge migration mechanism: the
fluctuation-assisted one, in which the electron dynamics is governed by
relatively slow fluctuations of the vibrational subsystem. We argue also that
the discussed methods and mechanisms can be relevant for other organic
macromolecular systems, such as conjugated polymers and molecular aggregates
Influence of Small-Scale Inhomogeneities on the Cosmological Consistency Tests
The current cosmological dark sector (dark matter plus dark energy) is
challenging our comprehension about the physical processes taking place in the
Universe. Recently, some authors tried to falsify the basic underlying
assumptions of such dark matter-dark energy paradigm. In this Letter, we show
that oversimplifications of the measurement process may produce false positives
to any consistency test based on the globally homogeneous and isotropic LCDM
model and its expansion history based on distance measurements. In particular,
when local inhomogeneity effects due to clumped matter or voids are taken into
account, an apparent violation of the basic assumptions ("Copernican
Principle") seems to be present. Conversely, the amplitude of the deviations
also probes the degree of reliability underlying the phenomenological
Dyer-Roeder procedure by confronting its predictions with the accuracy of the
weak lensing approach. Finally, a new method is devised to reconstruct the
effects of the inhomogeneities in a LCDM model, and some suggestions of how to
distinguish between clumpiness (or void) effects from different cosmologies are
discussed.Comment: 18 pages, 2 figures. Improved version accepted for publication as a
Letter in MNRA
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