14,209 research outputs found
Vibrational cooling, heating, and instability in molecular conducting junctions: Full counting statistics analysis
We study current-induced vibrational cooling, heating, and instability in a
donor-acceptor rectifying molecular junction using a full counting statistics
approach. In our model, electron-hole pair excitations are coupled to a given
molecular vibrational mode which is either harmonic or highly anharmonic. This
mode may be further coupled to a dissipative thermal environment. Adopting a
master equation approach, we confirm the charge and heat exchange fluctuation
theorem in the steady-state limit, for both harmonic and anharmonic models.
Using simple analytical expressions, we calculate the charge current and
several measures for the mode effective temperature. At low bias, we observe
the effect of bias-induced cooling of the vibrational mode. At higher bias, the
mode effective temperature is higher than the environmental temperature, yet
the junction is stable. Beyond that, once the vibrational mode (bias-induced)
excitation rate overcomes its relaxation rate, instability occurs. We identify
regimes of instability as a function of voltage bias and coupling to an
additional phononic thermal bath. Interestingly, we observe a reentrant
behavior where an unstable junction can properly behave at a high enough bias.
The mechanism for this behavior is discussed
A simple status quo that ensures participation (with application to efficient bargaining)
We consider Bayesian incentive-compatible mechanisms with independent types and either private values or interdependent values that satisfy a form of "congruence." We show that in these settings, interim participation constraints are satisfied when the status quo is the randomized allocation that has the same distribution as the equilibrium allocation in the mechanism. Moreover, when utilities are convex in the allocation, we can instead satisfy participation constraints with the deterministic status quo equal to the expected equilibrium allocation in the mechanism. For quasilinear settings, these observations imply the possibility of efficient bargaining when the status quo specifies the expected efficient decision provided that the total surplus is convex in the decision.Efficient property rights, asymmetric information bargaining, transaction costs
Twisted equivariant K-theory, groupoids and proper actions
In this paper we define twisted equivariant K-theory for actions of Lie
groupoids. For a Bredon-compatible Lie groupoid, this defines a periodic
cohomology theory on the category of finite CW-complexes with equivariant
stable projective bundles. A classification of these bundles is shown. We also
obtain a completion theorem and apply these results to proper actions of
groups.Comment: 26 page
Analysis of AIS Data of the Recluse Oil Field, Recluse, Wyoming
Airborne Imaging Spectrometer (AIS) data were flown over the Recluse, Wyoming oil field on September 9, 1984. Processing software was developed at Earth Satellite Corporation (EarthSat) for interactive analysis of the AIS data. EarthSat's AIS processing capabilities include destriping, solar irradiance corrections, residual calculations, geometric resampling, equal energy normalization, interactive spectral classifications and a variety of compressive algorithms to reduce the data to 8-bit format with a minimum of information loss. The in-house photolab facilities of EarthSat can routinely produce high-quality color renditions of the enhanced AIS data. A total of 80 lithologic samples were collected under the AIS flight lines. Correlation (within the atmospheric windows) between the laboratory and the AIS spectra of sample sites was generally poor. Reasonable correlation was only possible in large, freshly plowed fields. Mixed pixels and contrast between the natural and sample's surfaces were believed responsible for the poor correlation. Finally, a drift of approximately three channels was observed in the diffraction grating position within the 1.8 to 2.1 micron quadrant
A spin-boson thermal rectifier
Rectification of heat transfer in nanodevices can be realized by combining
the system inherent anharmonicity with structural asymmetry. we analyze this
phenomenon within the simplest anharmonic system -a spin-boson nanojunction
model. We consider two variants of the model that yield, for the first time,
analytical solutions: a linear separable model in which the heat reservoirs
contribute additively, and a non-separable model suitable for a stronger
system-bath interaction. Both models show asymmetric (rectifying) heat
conduction when the couplings to the heat reservoirs are different.Comment: 5 pages, 3 figures, RevTeX
Looking into DNA breathing dynamics via quantum physics
We study generic aspects of bubble dynamics in DNA under time dependent
perturbations, for example temperature change, by mapping the associated
Fokker-Planck equation to a quantum time-dependent Schroedinger equation with
imaginary time. In the static case we show that the eigenequation is exactly
the same as that of the -deformed nuclear liquid drop model, without the
issue of non-integer angular momentum. A universal breathing dynamics is
demonstrated by using an approximate method in quantum mechanics. The
calculated bubble autocorrelation function qualitatively agrees with
experimental data. Under time dependent modulations, utilizing the adiabatic
approximation, bubble properties reveal memory effects.Comment: 5 pages, 1 figur
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