2,860 research outputs found
Study of Apollo water impact. Volume 9 - Mode shapes and natural frequencies analysis Final report
Numerical analysis on vibrational modes and frequencies in Apollo water impac
Study of Apollo water impact. Volume 2 - Dynamic response of shells of revolution during vertical impact into water - No interaction Final report
Mathematical model for predicting dynamic response of thin elastic shells of revolution during water impac
Study of Apollo water impact. Volume 8 - Unsymmetric shells of revolution analysis Final report
Numerical analysis of static, and dynamic shell response to water impact load
Classification of Quantum Hall Universality Classes by $\ W_{1+\infty}\ $ symmetry
We show how two-dimensional incompressible quantum fluids and their
excitations can be viewed as edge conformal field theories,
thereby providing an algebraic characterization of incompressibility. The
Kac-Radul representation theory of the algebra leads then to
a purely algebraic complete classification of hierarchical quantum Hall states,
which encompasses all measured fractions. Spin-polarized electrons in
single-layer devices can only have Abelian anyon excitations.Comment: 11 pages, RevTeX 3.0, MPI-Ph/93-75 DFTT 65/9
Spontaneous symmetry breaking in the non-abelian anyon fluid
We study the theory of non-relativistic matter with non-Abelian U(2) Chern-Simons gauge interaction in (2+1) dimensions. We adopt the mean field approximation in the current-algebra formulation already applied to the Abelian anyons. We first show that this method is able to describe both ``boson-based'' and ``fermion-based'' anyons and yields consistent results over the whole range of fractional statistics. In the non-Abelian theory, we find a superfluid (and superconductive) phase, which is smoothly connected with the Abelian superfluid phase originally discovered by Laughlin. The characteristic massless excitation is the Goldstone particle of the specific mechanism of spontaneous symmetry breaking. An additional massive mode is found by diagonalizing the non-Abelian, non-local, Hamiltonian in the radial gauge
A note on the topological order of noncommutative Hall fluids
We evaluate the ground state degeneracy of noncommutative Chern-Simons models
on the two-torus, a quantity that is interpreted as the "topological order" of
associated phases of Hall fluids. We define the noncommutative theory via
T-duality from an ordinary Chern-Simons model with non-abelian 't Hooft
magnetic fluxes. Motivated by this T-duality, we propose a discrete family of
noncommutative, non-abelian fluid models, arising as a natural generalization
of the standard noncommutative Chern-Simons effective models. We compute the
topological order for these universality classes, and comment on their possible
microscopic interpretation.Comment: 14 page
(2+1)-Gravity with Moving Particles in an Instantaneous Gauge
By defining a regular gauge which is conformal-like and provides
instantaneous field propagation, we investigate classical solutions of
(2+1)-Gravity coupled to arbitrarily moving point-like particles. We show how
to separate field equations from self-consistent motion and we provide a
solution for the metric and the motion in the two-body case with arbitrary
speed, up to second order in the mass parameters.Comment: 16 pages, LaTeX, no figure
Non-Perturbative Particle Dynamics
We construct a non-perturbative, single-valued solution for the metric and
the motion of two interacting particles in ()-Gravity, by using a Coulomb
gauge of conformal type. The method provides the mapping from multivalued (
minkowskian ) coordinates to single-valued ones, which solves the non-abelian
monodromies due to particles's momenta and can be applied also to the general
N-body case.Comment: 11 pages, LaTeX, no figure
Thermal broadening of the Coulomb blockade peaks in quantum Hall interferometers
We demonstrate that the differential magnetic susceptibility of a fractional
quantum Hall disk, representing a Coulomb island in a Fabry--Perot
interferometer, is exactly proportional to the island's conductance and its
paramagnetic peaks are the equilibrium counterparts of the Coulomb blockade
conductance peaks. Using as a thermodynamic potential the partition functions
of the edge states' effective conformal field theory we find the positions of
the Coulomb blockade peaks, when the area of the island is varied, the
modulations of the distance between them as well as the thermal decay and
broadening of the peaks when temperature is increased. The finite-temperature
estimates of the peak's heights and widths could give important information
about the experimental observability of the Coulomb blockade. In addition, the
predicted peak asymmetry and displacement at finite temperature due to neutral
multiplicities could serve to distinguish different fractional quantum Hall
states with similar zero-temperature Coulomb blockade patterns.Comment: 6 pages, 6 figures; published versio
O(N) Sigma Model as a Three Dimensional Conformal Field Theory
We study a three dimensional conformal field theory in terms of its partition
function on arbitrary curved spaces. The large limit of the nonlinear sigma
model at the non-trivial fixed point is shown to be an example of a conformal
field theory, using zeta--function regularization. We compute the critical
properties of this model in various spaces of constant curvature (, , , , and ) and we argue that what distinguishes the
different cases is not the Riemann curvature but the conformal class of the
metric. In the case (constant negative curvature), the
symmetry is spontaneously broken at the critical point. In the case (constant positive curvature) we find that the free energy vanishes,
consistent with conformal equivalence of this manifold to , although the
correlation length is finite. In the zero curvature cases, the correlation
length is finite due to finite size effects. These results describe two
dimensional quantum phase transitions or three dimensional classical ones.Comment: 35 pages, TeX, (Revised version, to appear in Nucl. Phys. B--paper
shortened, a discussion added and other minor corrections
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