5,398 research outputs found
(p,q)-string in matrix-regularized membrane and type IIB duality
We consider a lightcone wrapped supermembrane compactified on 2-torus in the
matrix regularization. We examine the double dimensional reduction technique
and deduce the free matrix string of (p,q)-string in type IIB superstring
theory explicitly from the matrix-regularized wrapped supermembrane. In
addition we obtain the (2+1)-dimensional super Yang-Mills action in curved
background. We also examine the duality.Comment: 25 page
Wrapped membranes, matrix string theory and an infinite dimensional Lie algebra
We examine the algebraic structure of the matrix regularization for the
wrapped membrane on in the light-cone gauge. We give a
concrete representation for the algebra and obtain the matrix string theory
having the boundary conditions for the matrix variables corresponding to the
wrapped membrane, which is referred to neither Seiberg and Sen's arguments nor
string dualities. We also embed the configuration of the multi-wrapped membrane
in matrix string theory.Comment: 19 pages, 1 figure, references added, minor change
Comments on the global constraints in light-cone string and membrane theories
In the light-cone closed string and toroidal membrane theories, we associate
the global constraints with gauge symmetries. In the closed string case, we
show that the physical states defined by the BRS charge satisfy the
level-matching condition. In the toroidal membrane case, we show that the
Faddeev-Popov ghost and anti-ghost corresponding to the global constraints are
essentially free even if we adopt any gauge fixing condition for the local
constraint. We discuss the quantum double-dimensional reduction of the wrapped
supermembrane with the global constraints.Comment: 12 pages, typos corrected, to appear in JHE
Spontaneous Breakdown of U(1) symmetry in DLCQ without Zero Mode
We show that the spontaneous breakdown of U(1) symmetry in a Higgs model can
be described in discretized light cone formulation even by neglecting zero
mode. We obtain correctly the energy of a ground state with the symmetry
breakdown. We also show explicitly the presence of a Goldstone mode and its
absence when the U(1) symmetry is gauged. In spite of obtaining the favorable
results, we lose a merit in the formulation without zero modes that a naive
Fock vacuum is the true ground state.Comment: 7 page
Sliding Tokens on a Cactus
Given two independent sets I and J of a graph G, imagine that a token (coin) is placed on each vertex in I. Then, the Sliding Token problem asks if one could transforms I to J using a sequence of elementary steps, where each step requires sliding a token from one vertex to one of its neighbors, such that the resulting set of vertices where tokens are placed still remains independent. In this paper, we describe a polynomial-time algorithm for solving Sliding Token in case the graph G is a cactus. Our algorithm is designed based on two observations. First, all structures that forbid the existence of a sequence of token slidings between I and J, if exist, can be found in polynomial time. A no-instance may be easily deduced using this characterization. Second, without such forbidden structures, a sequence of token slidings between I and J does exist
Magnon-Hole Scattering and Charge Order in
The magnon thermal conductivity of the hole doped
spin ladders in has been investigated at low
doping levels . The analysis of reveals a strong
doping and temperature dependence of the magnon mean free path
which is a local probe for the interaction of magnons with
the doped holes in the ladders. In particular, this novel approach to studying
charge degrees of freedom via spin excitations shows that charge ordering of
the holes in the ladders leads to a freezing out of magnon-hole scattering
processes
Projectile-shape dependence of impact craters in loose granular media
We report on the penetration of cylindrical projectiles dropped from rest
into a dry, noncohesive granular medium. The cylinder length, diameter,
density, and tip shape are all explicitly varied. For deep penetrations, as
compared to the cylinder diameter, the data collapse onto a single scaling law
that varies as the 1/3 power of the total drop distance, the 1/2 power of
cylinder length, and the 1/6 power of cylinder diameter. For shallow
penetrations, the projectile shape plays a crucial role with sharper objects
penetrating deeper.Comment: 3 pages, 3 figures; experimen
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