91 research outputs found
Transient Temperature Dynamics of Reservoirs Connected Through an Open Quantum System
The dynamics of open quantum systems connected with several reservoirs
attract great attention due to its importance in quantum optics, biology,
quantum thermodynamics, transport phenomena, etc. In many problems, the Born
approximation is applicable which implies that the influence of the open
quantum system on the reservoirs can be neglected. However, in the case of a
long-time dynamics or mesoscopic reservoir, the reverse influence can be
crucial. In this paper, we investigate the transient dynamics of several
bosonic reservoirs connected through an open quantum system. We use an
adiabatic approach to study the temporal dynamics of temperatures of the
reservoirs during relaxation to thermodynamic equilibrium. We show that there
are various types of temperature dynamics that strongly depend on the values of
dissipative rates and initial temperatures. We demonstrate that temperatures of
the reservoirs can exhibit non-monotonic behavior. Moreover, there are moments
of time during which the reservoir with initially intermediate temperature
becomes the hottest or coldest reservoir. The obtained results pave the way for
managing energy flows in mesoscale and nanoscale systems
Molecular dynamics analysis of particle number fluctuations in the mixed phase of a first-order phase transition
Molecular dynamics simulations are performed for a finite non-relativistic
system of particles with Lennard-Jones potential. We study the effect of
liquid-gas mixed phase on particle number fluctuations in coordinate subspace.
A metastable region of the mixed phase, the so-called nucleation region, is
analyzed in terms of a non-interacting cluster model. Large fluctuations due to
spinodal decomposition are observed. They arise due to the interplay between
the size of the acceptance region and that of the liquid phase. These effects
are studied with a simple geometric model. The model results for the scaled
variance of particle number distribution are compared with those obtained from
the direct molecular dynamic simulations.Comment: 13 pages, 9 figure
The spall strength limit of matter at ultrahigh strain rates induced by laser shock waves
New results concerning the process of dynamic fracture of
materials (spallation) by laser-induced shock waves are presented.
The Nd-glass laser installations SIRIUS and KAMERTON were used
for generation of shock waves with pressure up to 1 Mbar in
plane Al alloy targets. The wavelengths of laser radiation were
1.06 and 0.53 μm, the target thickness was changed from
180 to 460 μm, and the laser radiation was focused in a
spot with a 1-mm diameter on the surface of AMg6M aluminum alloy
targets. Experimental results were compared to predictions of
a numerical code which employed a real semiempirical wide-range
equation of state. Strain rates in experiments were changed
from 106 to 5 × 107 s−1.
Two regimes of spallation were evidenced: the already known
dynamic regime and a new quasi-stationary regime. An ultimate
dynamic strength of 80 kbar was measured. Finally, experiments
on targets with artificial spall layers were performed showing
material hardening due to shock-wave compression
van der Waals Interactions and Hadron Resonance Gas: Role of resonance widths modeling on conserved charges fluctuations
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