62 research outputs found
Global quantum Hall phase diagram from visibility diagrams
We propose a construction of a global phase diagram for the quantum Hall
effect. This global phase diagram is based on our previous constructions of
visibility diagrams in the context of the Quantum Hall Effect. The topology of
the phase diagram we obtain is in good agreement with experimental observations
(when the spin effect can be neglected). This phase diagram does not show
floating.Comment: LaTeX2e, 9 pages, 5 eps figure
Temperature inversion symmetry in the Casimir effect with an antiperiodic boundary condition
We present explicitly another example of a temperature inversion symmetry in
the Casimir effect for a nonsymmetric boundary condition. We also give an
interpretation for our result.Comment: 4 page
RG Flow Irreversibility, C-Theorem and Topological Nature of 4D N=2 SYM
We determine the exact beta function and a RG flow Lyapunov function for N=2
SYM with gauge group SU(n). It turns out that the classical discriminants of
the Seiberg-Witten curves determine the RG potential. The radial
irreversibility of the RG flow in the SU(2) case and the non-perturbative
identity relating the -modulus and the superconformal anomaly, indicate the
existence of a four dimensional analogue of the c-theorem for N=2 SYM which we
formulate for the full SU(n) theory. Our investigation provides further
evidence of the essentially topological nature of the theory.Comment: 9 pages, LaTeX file. Discussion on WDVV and integrability. References
added. Version published in PR
Gauge Invariance and the Critical Properties of Quantum Hall Plateaux Transitions
A model consisting of a single massless scalar field with a topological
coupling to a pure gauge field is defined and studied. It possesses an SL(2,Z)
symmetry as a consequence of the gauge invariance. We propose that by adding
impurities the model can be used to describe transitions between Quantum Hall
plateaux. This leads to a correlation length exponent of 20/9, in excellent
agreement with the most recent experimental measurements.Comment: 25 pages, minor changes in data discussion, Section V on connection
with staircase model is expanded References added. Interpretive comments
added in section 3 about the critical condition. with improved terminolog
A Vector Non-abelian Chern-Simons Duality
Abelian Chern-Simons gauge theory is known to possess a `-self-dual'
action where its coupling constant is inverted {\it i.e.} . Here a vector non-abelian duality is found in the
pure non-abelian Chern-Simons action at the classical level. The dimensional
reduction of the dual Chern-Simons action to two-dimensions constitutes a dual
Wess-Zumino-Witten action already given in the literature.Comment: 14+1 pages, LaTeX file, no figures, version to appear in Phys. Rev
Duality and Universality for the Chern-Simons bosons
By mapping the relativistic version of the Chern-Simons-Landau-Ginzburg
theory in 2+1 dimensions to the 3D lattice Villain x-y model coupled with the
Chern-Simons gauge field, we investigate phase transitions of Chern-Simons
bosons in the limit of strong coupling. We construct algebraically exact
duality and flux attachment transformations of the lattice theories,
corresponding to analogous transformations in the continuum limit. These
transformations are used to convert the model with arbitrary fractional
Chern-Simons coefficient to a model with either zero or one.
Depending on this final value of , the phase transition in the original
model is either in the universality class of the 3D x-y model or a
``fermionic'' universality class, unless the irrelevant corrections of cubic
and higher power in momenta render the transition of the first order.Comment: 14 two-column pages, revtex 3.0, multicol and epsf.sty (optional),
one PostScript figure, Submitted to Phys. Rev. B The changes intended to
simplify the arguments and eliminate logical gaps. We also show how the
filling factor is changed by the duality transformatio
Radiative Corrections to the Casimir Energy
The lowest radiative correction to the Casimir energy density between two
parallel plates is calculated using effective field theory. Since the
correlators of the electromagnetic field diverge near the plates, the
regularized energy density is also divergent. However, the regularized integral
of the energy density is finite and varies with the plate separation L as
1/L^7. This apparently paradoxical situation is analyzed in an equivalent, but
more transparent theory of a massless scalar field in 1+1 dimensions confined
to a line element of length L and satisfying Dirichlet boundary conditions.Comment: 7 pages, Late
SO(5) Invariance and Effective Field Theory for High-Tc Superconductors
We set up the effective field theories which describe the SO(5)-invariant
picture of the high-Tc cuprates in various regimes. We use these to get
quantitative conclusions concerning the size of SO(5)-breaking effects. We
consider two applications in detail: (i) the thermodynamic free energy, which
describe the phase diagram and critical behaviour, and (ii) the Lagrangian
governing the interactions of the pseudo-Goldstone bosons with each other and
with the electron quasiparticles deep within the ordered phases. We use these
effective theories to obtain predictions for the critical behaviour near the
possible bicritical point and the pseudo-Goldstone boson dispersion relations,
as well as some preliminary results concerning their contribution to response
functions. We systematically identify which predictions are independent of the
microscopic details of the underlying electron dynamics, and which depend on
more model-dependent assumptions.Comment: 40 pages, plain TeX, companion article for the letter
cond-mat/961107
On S-duality in (2+1)-Chern-Simons Supergravity
Strong/weak coupling duality in Chern-Simons supergravity is studied. It is
argued that this duality can be regarded as an example of superduality. The use
of supergroup techniques for the description of Chern-Simons supergravity
greatly facilitates the analysis.Comment: 10+1 pages, latex, no figure
A review of the Cis-Andean species of Hemibrycon Günther (Teleostei: Characiformes: Characidae: Stevardiinae), with description of two new species
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