29,883 research outputs found
Non-Extensive Bose-Einstein Condensation Model
The imperfect Boson gas supplemented with a gentle repulsive interaction is
completely solved. In particular it is proved that it has non-extensive
Bose-Einstein condensation, i.e., there is condensation without macroscopic
occupation of the ground state (k=0) level
Long spin relaxation times in wafer scale epitaxial graphene on SiC(0001)
We developed an easy, upscalable process to prepare lateral spin-valve
devices on epitaxially grown monolayer graphene on SiC(0001) and perform
nonlocal spin transport measurements. We observe the longest spin relaxation
times tau_S in monolayer graphene, while the spin diffusion coefficient D_S is
strongly reduced compared to typical results on exfoliated graphene. The
increase of tau_S is probably related to the changed substrate, while the cause
for the small value of D_S remains an open question.Comment: 16 pages, 3 figures, 1 tabl
Application of ERTS-1 imagery in coastal studies
The basic ERTS output is four black-and-white photographs presenting the same scene recorded in each multispectral scanner band. Mosaics covering large regions at a 1:250,000 scale can be compiled from these photographs. Office study of the image of each band separately, in combination with other bands, and in conjunction with other available data (navigation charts, tide tables, etc.) permits extraction of data useful in coastal engineering planning and coastal processes studies. Specific examples in which significant information on regional shoreline configuration or nearshore water movements has been obtained from unenhanced ERTS imagery are: (1) tidal inlet configuration; (2) navigation information; and (3) nearshore water movements
Application of NASA ERTS-1 satellite imagery in coastal studies
There are no author-identified significant results in this report. Review of ERTS-1 imagery indicates that it contains information of great value in coastal engineering studies. A brief introduction is given to the methods by which imagery is generated, and examples of its application to coastal engineering. Specific applications discussed include study of the movement of coastal and nearshore sediment-laden water masses and information for planning and construction in remote areas of the world
The Canonical Perfect Bose Gas in Casimir Boxes
We study the problem of Bose-Einstein condensation in the perfect Bose gas in
the canonical ensemble, in anisotropically dilated rectangular parallelpipeds
(Casimir boxes). We prove that in the canonical ensemble for these anisotropic
boxes there is the same type of generalized Bose-Einstein condensation as in
the grand-canonical ensemble for the equivalent geometry. However the amount of
condensate in the individual states is different in some cases and so are the
fluctuations.Comment: 23 page
Localized states influence spin transport in epitaxial graphene
We developed a spin transport model for a diffusive channel with coupled
localized states that result in an effective increase of spin precession
frequencies and a reduction of spin relaxation times in the system. We apply
this model to Hanle spin precession measurements obtained on monolayer
epitaxial graphene on SiC(0001) (MLEG). Combined with newly performed
measurements on quasi-free-standing monolayer epitaxial graphene on SiC(0001)
our analysis shows that the different values for the diffusion coefficient
measured in charge and spin transport measurements in MLEG and the high values
for the spin relaxation time can be explained by the influence of localized
states arising from the buffer layer at the interface between the graphene and
the SiC surface.Comment: 6 pages, 3 figures, including supplementary materia
A Multicanonical Algorithm and the Surface Free Energy in SU(3) Pure Gauge Theory
We present a multicanonical algorithm for the SU(3) pure gauge theory at the
deconfinement phase transition. We measure the tunneling times for lattices of
size L^3x2 for L=8,10, and 12. In contrast to the canonical algorithm the
tunneling time increases only moderately with L. Finally, we determine the
interfacial free energy applying the multicanonical algorithm.Comment: 6 pages, HLRZ-92-3
Properties of the non-Gaussian fixed point in 4D compact U(1) lattice gauge theory
We examine selected properties of the gauge-ball spectrum and fermionic
variables in the vicinity of the recently discussed non-Gaussian fixed point of
4D compact U(1) lattice gauge theory within the quenched approximation.
Approaching the critical point from within the confinement phase, our data
support scaling of gauge-ball states in units of the string tension
square root. The analysis of the chiral condensate within the framework of a
scaling form for the equation of state suggests non mean-field values for the
magnetic exponents and .Comment: 73K postscript fil
Large deviations for ideal quantum systems
We consider a general d-dimensional quantum system of non-interacting
particles, with suitable statistics, in a very large (formally infinite)
container. We prove that, in equilibrium, the fluctuations in the density of
particles in a subdomain of the container are described by a large deviation
function related to the pressure of the system. That is, untypical densities
occur with a probability exponentially small in the volume of the subdomain,
with the coefficient in the exponent given by the appropriate thermodynamic
potential. Furthermore, small fluctuations satisfy the central limit theorem.Comment: 28 pages, LaTeX 2
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