44,434 research outputs found
Intrinsic rotation drive by collisionless trapped electron mode turbulence
Both the parallel residual stress and parallel turbulent acceleration driven
by electrostatic collisionsless trapped electron mode (CTEM) turbulence are
calculated analytically using gyrokinetic theory. Quasilinear results show that
the parallel residual stress contributes an outward flux of co-current rotation
for normal magnetic shear and turbulence intensity profile increasing outward.
This may induce intrinsic counter-current rotation or flattening of the
co-current rotation profile. The parallel turbulent acceleration driven by CTEM
turbulence vanishes, due to the absence of a phase shift between density
fluctuation and ion pressure fluctuation. This is different from the case of
ion temperature gradient (ITG) turbulence, for which the turbulent acceleration
can provide co-current drive for normal magnetic shear and turbulence intensity
profile increasing outward. Its order of magnitude is predicted to be the same
as that of the divergence of the residual stress [Lu Wang and P.H. Diamond,
Phys. Rev. Lett. {\bf 110}, 265006 (2013)]. A possible connection of these
theoretical results to experimental observations of electron cyclotron heating
effects on toroidal rotation is discussed.Comment: Accepted by Phys. Plasma
Antimagnetic Rotation Band in Nuclei: A Microscopic Description
Covariant density functional theory and the tilted axis cranking method are
used to investigate antimagnetic rotation (AMR) in nuclei for the first time in
a fully self-consistent and microscopic way. The experimental spectrum as well
as the B(E2) values of the recently observed AMR band in 105Cd are reproduced
very well. This gives a further strong hint that AMR is realized in specific
bands in nuclei.Comment: 10 pages, 4 figure
Ballistic transport at room temperature in micrometer size multigraphene
The intrinsic values of the carriers mobility and density of the graphene
layers inside graphite, the well known structure built on these layers in the
Bernal stacking configuration, are not well known mainly because most of the
research was done in rather bulk samples where lattice defects hide their
intrinsic values. By measuring the electrical resistance through
microfabricated constrictions in micrometer small graphite flakes of a few tens
of nanometers thickness we studied the ballistic behavior of the carriers. We
found that the carriers' mean free path is micrometer large with a mobility
cm/Vs and a carrier density cm per graphene layer at room temperature. These distinctive
transport and ballistic properties have important implications for
understanding the values obtained in single graphene and in graphite as well as
for implementing this last in nanoelectronic devices.Comment: 6 pages, 6 figure
Random solids and random solidification: What can be learned by exploring systems obeying permanent random constraints?
In many interesting physical settings, such as the vulcanization of rubber,
the introduction of permanent random constraints between the constituents of a
homogeneous fluid can cause a phase transition to a random solid state. In this
random solid state, particles are permanently but randomly localized in space,
and a rigidity to shear deformations emerges. Owing to the permanence of the
random constraints, this phase transition is an equilibrium transition, which
confers on it a simplicity (at least relative to the conventional glass
transition) in the sense that it is amenable to established techniques of
equilibrium statistical mechanics. In this Paper I shall review recent
developments in the theory of random solidification for systems obeying
permanent random constraints, with the aim of bringing to the fore the
similarities and differences between such systems and those exhibiting the
conventional glass transition. I shall also report new results, obtained in
collaboration with Weiqun Peng, on equilibrium correlations and
susceptibilities that signal the approach of the random solidification
transition, discussing the physical interpretation and values of these
quantities both at the Gaussian level of approximation and, via a
renormalization-group approach, beyond.Comment: Paper presented at the "Unifying Concepts in Glass Physics" workshop,
International Centre for Theoretical Physics, Trieste, Italy (September
15-18, 1999
In-medium Properties of as a KN structure in Relativistic Mean Field Theory
The properties of nuclear matter are discussed with the relativistic
mean-field theory (RMF).Then, we use two models in studying the in-medium
properties of : one is the point-like in the usual RMF and
the other is a KN structure for the pentaquark. It is found that the
in-medium properties of are dramatically modified by its internal
structure. The effective mass of in medium is, at normal nuclear
density, about 1030 MeV in the point-like model, while it is about 1120 MeV in
the model of KN pentaquark. The nuclear potential depth of in
the KN model is approximately -37.5 MeV, much shallower than -90 MeV in
the usual point-like RMF model.Comment: 8 pages, 5 figure
Inf-convolution of G-expectations
In this paper we will discuss the optimal risk transfer problems when risk
measures are generated by G-expectations, and we present the relationship
between inf-convolution of G-expectations and the inf-convolution of drivers G.Comment: 23 page
Probing multipartite entanglement in a coupled Jaynes-Cummings system
We show how to probe multipartite entanglement in coupled Jaynes-Cummings
cells where the degrees of freedom are the electronic energies of each of the
atoms in separate single-mode cavities plus the single-mode fields
themselves. Specifically we propose probing the combined system as though it is
a dielectric medium. The spectral properties and transition rates directly
reveal multipartite entanglement signatures. It is found that the Hilbert space
of the cell system can be confined to the totally symmetric subspace of two
states only that are maximally-entangled W states with 2N degrees of freedom
Effects of using different plasmonic metals in metal/dielectric/metal subwavelength waveguides on guided dispersion characteristics
The fundamental guided dispersion characteristics of guided light in a
subwavelength dielectric slit channel embedded by two different plasmonic
metals are investigated when varying the gap width. As a result, an overall and
salient picture of the guided dispersion characteristics is obtained over a
wide spectrum range below and above the plasma frequencies of the two different
plasmonic metals, which is important preliminary information for analyzing this
type of subwavelength waveguide. In particular, the effects of using two
different metals on the guided mode dispersions are emphasized in comparison
with the effects of using the same plasmonic metal cladding.Comment: 13 pages, 3 figures, typos corrected, reference added, text modifie
Spin and Charge Structure of the Surface States in Topological Insulators
We investigate the spin and charge densities of surface states of the
three-dimensional topological insulator , starting from the continuum
description of the material [Zhang {\em et al.}, Nat. Phys. 5, 438 (2009)]. The
spin structure on surfaces other than the 111 surface has additional complexity
because of a misalignment of the contributions coming from the two sublattices
of the crystal. For these surfaces we expect new features to be seen in the
spin-resolved ARPES experiments, caused by a non-helical spin-polarization of
electrons at the individual sublattices as well as by the interference of the
electron waves emitted coherently from two sublattices. We also show that the
position of the Dirac crossing in spectrum of surface states depends on the
orientation of the interface. This leads to contact potentials and surface
charge redistribution at edges between different facets of the crystal.Comment: Use the correct spin operator. Changes affect the surface states spin
structure, but not the spectru
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