1,598 research outputs found
The embedding structure and the shift operator of the U(1) lattice current algebra
The structure of block-spin embeddings of the U(1) lattice current algebra is
described. For an odd number of lattice sites, the inner realizations of the
shift automorphism areclassified. We present a particular inner shift operator
which admits a factorization involving quantum dilogarithms analogous to the
results of Faddeev and Volkov.Comment: 14 pages, Plain TeX; typos and a terminological mishap corrected;
version to appear in Lett.Math.Phy
Representation Theory of Lattice Current Algebras
Lattice current algebras were introduced as a regularization of the left- and
right moving degrees of freedom in the WZNW model. They provide examples of
lattice theories with a local quantum symmetry U_q(\sg). Their representation
theory is studied in detail. In particular, we construct all irreducible
representations along with a lattice analogue of the fusion product for
representations of the lattice current algebra. It is shown that for an
arbitrary number of lattice sites, the representation categories of the lattice
current algebras agree with their continuum counterparts.Comment: 35 pages, LaTeX file, the revised version of the paper, to be
published in Commun. Math. Phys. , the definition of the fusion product for
lattice current algebras is correcte
2D Conformal Field Theories and Holography
It is known that the chiral part of any 2d conformal field theory defines a
3d topological quantum field theory: quantum states of this TQFT are the CFT
conformal blocks. The main aim of this paper is to show that a similar CFT/TQFT
relation exists also for the full CFT. The 3d topological theory that arises is
a certain ``square'' of the chiral TQFT. Such topological theories were studied
by Turaev and Viro; they are related to 3d gravity. We establish an
operator/state correspondence in which operators in the chiral TQFT correspond
to states in the Turaev-Viro theory. We use this correspondence to interpret
CFT correlation functions as particular quantum states of the Turaev-Viro
theory. We compute the components of these states in the basis in the
Turaev-Viro Hilbert space given by colored 3-valent graphs. The formula we
obtain is a generalization of the Verlinde formula. The later is obtained from
our expression for a zero colored graph. Our results give an interesting
``holographic'' perspective on conformal field theories in 2 dimensions.Comment: 29+1 pages, many figure
Physical phase space of lattice Yang-Mills theory and the moduli space of flat connections on a Riemann surface
It is shown that the physical phase space of \g-deformed Hamiltonian
lattice Yang-Mills theory, which was recently proposed in refs.[1,2], coincides
as a Poisson manifold with the moduli space of flat connections on a Riemann
surface with handles and therefore with the physical phase space of
the corresponding -dimensional Chern-Simons model, where and are
correspondingly a total number of links and vertices of the lattice. The
deformation parameter \g is identified with and is an
integer entering the Chern-Simons action.Comment: 12 pages, latex, no figure
Fractional and unquantized dc voltage generation in THz-driven semiconductor superlattices
We consider the spontaneous creation of a dc voltage across a strongly
coupled semiconductor superlattice subjected to THz radiation. We show that the
dc voltage may be approximately proportional either to an integer or to a half-
integer multiple of the frequency of the applied ac field, depending on the
ratio of the characteristic scattering rates of conducting electrons. For the
case of an ac field frequency less than the characteristic scattering rates, we
demonstrate the generation of an unquantized dc voltage.Comment: 6 pages, 3 figures, RevTEX, EPSF. Revised version v3: corrected typo
Linear magnetoresistance in compensated graphene bilayer
We report a nonsaturating linear magnetoresistance in charge-compensated
bilayer graphene in a temperature range from 1.5 to 150 K. The observed linear
magnetoresistance disappears away from charge neutrality ruling out the
traditional explanation of the effect in terms of the classical random resistor
network model. We show that experimental results qualitatively agree with a
phenomenological two-fluid model taking into account electron-hole
recombination and finite-size sample geometry
Matrix equations and trilinear commutation relations
In this paper we discuss a general algebraic approach to treating static
equations of matrix models with a mass-like term. In this approach the
equations of motions are considered as consequence of parafermi-like trilinear
commutation relations. In this context we consider several solutions, including
construction of noncommutative spheres. The equivalence of fuzzy spheres and
parafermions is underlined.Comment: 10 pages, an incorrect claim is removed, one reference is adde
Electroproduction, photoproduction, and inverse electroproduction of pions in the first resonance region
Methods are set forth for determining the hadron electromagnetic structure in
the sub--threshold timelike region of the virtual-photon ``mass'' and
for investigating the nucleon weak structure in the spacelike region from
experimental data on the process at low energies. These
methods are formulated using the unified description of photoproduction,
electroproduction, and inverse electroproduction of pions in the first
resonance region in the framework of the dispersion-relation model and on the
basis of the model-independent properties of inverse electroproduction.
Applications of these methods are also shown.Comment: The revised published version; Revtex4, 18 pages, 6 figure
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