1,228 research outputs found
Temperature Dependence of Magnetophonon Resistance Oscillations in GaAs/AlAs Heterostructures at High Filling Factors
The temperature dependence of phonon-induced resistance oscillations has been
investigated in two-dimensional electron system with moderate mobility at large
filling factors at temperature range T = 7.4 - 25.4 K. The amplitude of
phonon-induced oscillations has been found to be governed by quantum relaxation
time which is determined by electron-electron interaction effects. This is in
agreement with results recently obtained in ultra-high mobility two-dimensional
electron system with low electron density [A. T. Hatke et al., Phys. Rev. Lett.
102, 086808 (2009)]. The shift of the main maximum of the magnetophonon
resistance oscillations to higher magnetic fields with increasing temperature
is observed.Comment: 5 pages, 4 figure
Photocurrent, Rectification, and Magnetic Field Symmetry of Induced Current Through Quantum Dots
We report mesoscopic dc current generation in an open chaotic quantum dot
with ac excitation applied to one of the shape-defining gates. For excitation
frequencies large compared to the inverse dwell time of electrons in the dot
(i.e., GHz), we find mesoscopic fluctuations of induced current that are fully
asymmetric in the applied perpendicular magnetic field, as predicted by recent
theory. Conductance, measured simultaneously, is found to be symmetric in
field. In the adiabatic (i.e., MHz) regime, in contrast, the induced current is
always symmetric in field, suggesting its origin is mesoscopic rectification.Comment: related papers at http://marcuslab.harvard.ed
Matrix and vector models in the strong coupling limit
In this paper we consider matrix and vector models in the large N limit ( matrices and vectors with N^{2} components). For the case of
zero-dimensional model (D=0) it is proved that in the strong coupling limit statistical sums of both models coincide up to a coefficient. This
is also true for D=1.Comment: 8 page
Coherent radiation from neutral molecules moving above a grating
We predict and study the quantum-electrodynamical effect of parametric
self-induced excitation of a molecule moving above the dielectric or conducting
medium with periodic grating. In this case the radiation reaction force
modulates the molecular transition frequency which results in a parametric
instability of dipole oscillations even from the level of quantum or thermal
fluctuations. The present mechanism of instability of electrically neutral
molecules is different from that of the well-known Smith-Purcell and transition
radiation in which a moving charge and its oscillating image create an
oscillating dipole.
We show that parametrically excited molecular bunches can produce an easily
detectable coherent radiation flux of up to a microwatt.Comment: 4 page
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