32,647 research outputs found
Two-dimensional gases of generalized statistics in a uniform magnetic field
We study the low temperature properties of two-dimensional ideal gases of
generalized statistics in a uniform magnetic field. The generalized statistics
considered here are the parafermion statistics and the exclusion statistics.
Similarity in the behaviours of the parafermion gas of finite order and the
gas with exclusion coefficient at very low temperatures is noted. These
two systems become exactly equivalent at . Qumtum Hall effect with these
particles as charge carriers is briefly discussed.Comment: Latex file, 14 pages, 5 figures available on reques
Thermal capacitator design rationale. Part 1: Thermal and mechanical property data for selected materials potentially useful in thermal capacitor design and construction
The thermal properties of paraffin hydrocarbons and hydrocarbon mixtures which may be used as the phase change material (PCM) in thermal capacitors are discussed. The paraffin hydrocarbons selected for consideration are those in the range from C11H24 (n-Undecane) to C20H42 (n-Eicosane). A limited amount of data is included concerning other properties of paraffin hydrocarbons and the thermal and mechanical properties of several aluminum alloys which may find application as constructional materials. Data concerning the melting temperature, transition temperature, latent heat of fusion, heat of transition, specific heat, and thermal conductivity of pure and commercial grades of paraffin hydrocarbons are given. An index of companies capable of producing paraffin hydrocarbons and information concerning the availability of various grades (purity levels) is provided
Hole burning in a nanomechanical resonator coupled to a Cooper pair box
We propose a scheme to create holes in the statistical distribution of
excitations of a nanomechanical resonator. It employs a controllable coupling
between this system and a Cooper pair box. The success probability and the
fidelity are calculated and compared with those obtained in the atom-field
system via distinct schemes. As an application we show how to use the
hole-burning scheme to prepare (low excited) Fock states.Comment: 7 pages, 10 figure
Metal-Insulator Transition of the LaAlO3-SrTiO3 Interface Electron System
We report on a metal-insulator transition in the LaAlO3-SrTiO3 interface
electron system, of which the carrier density is tuned by an electric gate
field. Below a critical carrier density n_c ranging from 0.5-1.5 * 10^13/cm^2,
LaAlO3-SrTiO3 interfaces, forming drain-source channels in field-effect devices
are non-ohmic. The differential resistance at zero channel bias diverges within
a 2% variation of the carrier density. Above n_c, the conductivity of the ohmic
channels has a metal-like temperature dependence, while below n_c conductivity
sets in only above a threshold electric field. For a given thickness of the
LaAlO3 layer, the conductivity follows a sigma_0 ~(n - n_c)/n_c characteristic.
The metal-insulator transition is found to be distinct from that of the
semiconductor 2D systems.Comment: 4 figure
Representation of SO(3) Group by a Maximally Entangled State
A representation of the SO(3) group is mapped into a maximally entangled two
qubit state according to literatures. To show the evolution of the entangled
state, a model is set up on an maximally entangled electron pair, two electrons
of which pass independently through a rotating magnetic field. It is found that
the evolution path of the entangled state in the SO(3) sphere breaks an odd or
even number of times, corresponding to the double connectedness of the SO(3)
group. An odd number of breaks leads to an additional phase to the
entangled state, but an even number of breaks does not. A scheme to trace the
evolution of the entangled state is proposed by means of entangled photon pairs
and Kerr medium, allowing observation of the additional phase.Comment: 4 pages, 3 figure
On the Connection Between Momentum Cutoff and Operator Cutoff Regularizations
Operator cutoff regularization based on the original Schwinger's proper-time
formalism is examined. By constructing a regulating smearing function for the
proper-time integration, we show how this regularization scheme simulates the
usual momentum cutoff prescription yet preserves gauge symmetry even in the
presence of the cutoff scales. Similarity between the operator cutoff
regularization and the method of higher (covariant) derivatives is also
observed. The invariant nature of the operator cutoff regularization makes it a
promising tool for exploring the renormalization group flow of gauge theories
in the spirit of Wilson-Kadanoff blocking transformation.Comment: 28 pages in plain TeX, no figures. revised and expande
Flow Equations for U_k and Z_k
By considering the gradient expansion for the wilsonian effective action S_k
of a single component scalar field theory truncated to the first two terms, the
potential U_k and the kinetic term Z_k, I show that the recent claim that
different expansion of the fluctuation determinant give rise to different
renormalization group equations for Z_k is incorrect. The correct procedure to
derive this equation is presented and the set of coupled differential equations
for U_k and Z_k is definitely established.Comment: 5 page
Effect of excluded volume on the dipole moments of chain molecules
Dielectric constants have been determined for dimethylsiloxane chains (CH3)3Si[OSi(CH3)2]x OSi(CH3)3 in the thermodynamically good solvent cyclohexane and in the undiluted state, for degrees of polymerization x + 1 ranging from 102 to 103, at a number of temperatures in the range 10–60 °C. These data indicate that at constant temperature the dipole moment ratio 〈μ2〉/nm2〈μ2〉∕nm2 (where 〈μ2〉〈μ2〉 is the mean‐square dipole moment of a chain consisting of n = 2x + 2 bond dipoles of magnitude m) is independent of chain length, as has been predicted for chains of such structural symmetry. Unfortunately, comparison of the experimental values of the dipole moment ratio with those predicted from rotational isomeric state theory is complicated by pronounced specific solvent effects and comparison of experimental and theoretical values of d ln 〈μ2〉/dT〈μ2〉∕dT is also difficult because of the very small magnitude of this coefficient.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69812/2/JCPSA6-59-7-3825-1.pd
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