3,712 research outputs found
Haldane Exclusion Statistics and the Boltzmann Equation
We generalize the collision term in the one-dimensional Boltzmann-Nordheim
transport equation for quasiparticles that obey the Haldane exclusion
statistics. For the equilibrium situation, this leads to the ``golden rule''
factor for quantum transitions. As an application of this, we calculate the
density response function of a one-dimensional electron gas in a periodic
potential, assuming that the particle-hole excitations are quasiparticles
obeying the new statistics. We also calculate the relaxation time of a nuclear
spin in a metal using the modified golden rule.Comment: version accepted for publication in J. of Stat. Phy
Re-equilibration after quenches in athermal martensites:Conversion-delays for vapour to liquid domain-wall phases
Entropy barriers and ageing states appear in martensitic
structural-transition models, slowly re-equilibrating after temperature
quenches, under Monte Carlo dynamics. Concepts from protein folding and ageing
harmonic oscillators turn out to be useful in understanding these
nonequilibrium evolutions. We show how the athermal, non-activated delay time
for seeded parent-phase austenite to convert to product-phase martensite,
arises from an identified entropy barrier in Fourier space. In an ageing state
of low Monte Carlo acceptances, the strain structure factor makes
constant-energy searches for rare pathways, to enter a Brillouin zone `golf
hole' enclosing negative energy states, and to suddenly release entropically
trapped stresses. In this context, a stress-dependent effective temperature can
be defined, that re-equilibrates to the quenched bath temperature.Comment: 11 pages, 12 figures. Under process with Phys. Rev. B (2015
End wall flows in rotors and stators of a single stage compressor
A computer code for solving the parabolized Navier-Stokes equations for internal flows was developed. Oscillations that develop in the calculation procedure are discussed. The measurements made in the hub and annulus wall boundary layers are summarized. The flow in the hub wall boundary layer, starting ahead of the inlet guide vanes to the inlet of the rotor is traced
A growth walk model for estimating the canonical partition function of Interacting Self Avoiding Walk
We have explained in detail why the canonical partition function of
Interacting Self Avoiding Walk (ISAW), is exactly equivalent to the
configurational average of the weights associated with growth walks, such as
the Interacting Growth Walk (IGW), if the average is taken over the entire
genealogical tree of the walk. In this context, we have shown that it is not
always possible to factor the the density of states out of the canonical
partition function if the local growth rule is temperature-dependent. We have
presented Monte Carlo results for IGWs on a diamond lattice in order to
demonstrate that the actual set of IGW configurations available for study is
temperature-dependent even though the weighted averages lead to the expected
thermodynamic behavior of Interacting Self Avoiding Walk (ISAW).Comment: Revised version consisting of 12 pages (RevTeX manuscript, plus three
.eps figure files); A few sentences in the second paragraph on Page 4 are
rewritten so as to make the definition of the genealogical tree, , clearer. Also, the second equality of Eq.(1) on Page 4, and its
corresponding statement below have been remove
Magnetic phenomena at and near nu =1/2 and 1/4: theory, experiment and interpretation
I show that the hamiltonian theory of Composite Fermions (CF) is capable of
yielding a unified description in fair agreement with recent experiments on
polarization P and relaxation rate 1/T_1 in quantum Hall states at filling nu =
p/(2ps+1), at and near nu = 1/2 and 1/4, at zero and nonzero temperatures. I
show how rotational invariance and two dimensionality can make the underlying
interacting theory behave like a free one in a limited context.Comment: Latex 4 pages, 2 figure
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