6,465 research outputs found
Kinetic Theory of Transient Condensation and Evaporation at a Plane Surface
The phenomenon of transient condensation onto, or evaporation from, a liquid sheet in contact
with its pure vapor is treated from a kinetic theory viewpoint. The Maxwell moment method is used
to formulate the detailed transient problem. A steady surface mass flux rate exists for times large in
comparison with the collision time, that is, in the continuum regime, and explicit formulas are given
for this limit. The complete gasdynamic field, however, is nonsteady for all times. The calculations are
carried out utilizing four moments, and the effects of incorporating additional moments are negligible.
Finally, the analysis is extended to incorporate imperfect mass and temperature accommodation.
Examination of the transient solution and a matched asymptotic "quasisteady" solution shows that
the gasdynamic field consists of a diffusion process near the liquid surface coupled through an expansion
or compression wave to the constant far field state
On the perturbative expansion of boundary reflection factors of the supersymmetric sinh-Gordon model
The supersymmetric sinh-Gordon model on a half-line with integrable boundary
conditions is considered perturbatively to verify conjectured exact reflection
factors to one loop order. Propagators for the boson and fermion fields
restricted to a half-line contain several novel features and are developed as
prerequisites for the calculations.Comment: 19 pages, 2 figure
Exact Haldane mapping for all and super universality in spin chains
The low energy dynamics of the anti-ferromagnetic Heisenberg spin chain
in the semiclassical limit is known to map onto the O(3) nonlinear
model with a term in 1+1 dimension. Guided by the underlying
dual symmetry of the spin chain, as well as the recently established
topological significance of "dangling edge spins," we report an {\em exact}
mapping onto the O(3) model that avoids the conventional large
approximation altogether. Our new methodology demonstrates all the super
universal features of the angle concept that previously arose in the
theory of the quantum Hall effect. It explains why Haldane's original ideas
remarkably yield the correct answer in spite of the fundamental complications
that generally exist in the idea of semiclassical expansions
Nanoindentation Technique for Characterizing Cantilever Beam Style RF Microelectromechanical Systems (MEMS) Switches
A nanoindentation technique was used to mechanically actuate a radio frequency micro-switch along with the measurement of contact resistance to investigate its applicability to characterize deflection and contact resistance behaviors of micro-sized cantilever beam switches. The resulting load–displacement relationship showed a discontinuity in slope when the micro-switch closed. The measured spring constants reasonably agreed with theoretical values obtained from the simple beam models. The change in contact resistance during test clearly indicated micro-switch closure but it did not coincide exactly with the physical contact between two electric contacts due to a resistive contaminated film
RVB gauge theory and the Topological degeneracy in the Honeycomb Kitaev model
We relate the Z gauge theory formalism of the Kitaev model to the SU(2)
gauge theory of the resonating valence bond (RVB) physics. Further, we
reformulate a known Jordan-Wigner transformation of Kitaev model on a torus in
a general way that shows that it can be thought of as a Z gauge fixing
procedure. The conserved quantities simplify in terms of the gauge invariant
Jordan-Wigner fermions, enabling us to construct exact eigen states and
calculate physical quantities. We calculate the fermionic spectrum for flux
free sector for different gauge field configurations and show that the ground
state is four-fold degenerate on a torus in thermodynamic limit. Further on a
torus we construct four mutually anti-commuting operators which enable us to
prove that all eigenstates of this model are four fold degenerate in
thermodynamic limit.Comment: 12 pages, 3 figures. Added affiliation and a new section,
'Acknowledgements'.Typos correcte
Origin of charge density wave formation in insulators from a high resolution photoemission study of BaIrO3
We investigate the origin of charge density wave (CDW) formation in
insulators by studying BaIrO3 using high resolution (1.4 meV) photoemission
spectroscopy. The spectra reveal the existence of localized density of states
at the Fermi level in the vicinity of room temperature. These localized states
are found to vanish as the temperature is lowered thereby, opening a soft gap
at the Fermi level, as a consequence of CDW transition. In addition, the energy
dependence of the spectral density of states reveals the importance of magnetic
interactions, rather than well-known Coulomb repulsion effect, in determining
the electronic structure thereby implying a close relationship between
ferromagnetism and CDW observed in this compound. Also, Ba core level spectra
surprisingly exhibit an unusual behavior prior to CDW transition.Comment: 4 pages, 4 figures. To appear in Physical Review Letter
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