515 research outputs found

### Background Independent Algebraic Structures in Closed String Field Theory

We construct a Batalin-Vilkovisky (BV) algebra on moduli spaces of Riemann
surfaces. This algebra is background independent in that it makes no reference
to a state space of a conformal field theory. Conformal theories define a
homomorphism of this algebra to the BV algebra of string functionals. The
construction begins with a graded-commutative free associative algebra \C
built from the vector space whose elements are orientable subspaces of moduli
spaces of punctured Riemann surfaces. The typical element here is a surface
with several connected components. The operation $\Delta$ of sewing two
punctures with a full twist is shown to be an odd, second order derivation that
squares to zero. It follows that (\C, \Delta) is a Batalin-Vilkovisky
algebra. We introduce the odd operator $\delta = \partial + \hbar\Delta$, where
$\partial$ is the boundary operator. It is seen that $\delta^2=0$, and that
consistent closed string vertices define a cohomology class of $\delta$. This
cohomology class is used to construct a Lie algebra on a quotient space of
\C. This Lie algebra gives a manifestly background independent description of
a subalgebra of the closed string gauge algebra.Comment: phyzzx.tex, MIT-CTP-234

### Adjoint torelons, and the persistence of color electric flux tubes in the deconfined phase

It is argued that the adjoint torelon loop, i.e. a Polyakov loop in the
adjoint representation running in a spatial, rather than temporal, direction,
is an observable which is sensitive to the presence of long color electric flux
tubes at high temperatures. We show via lattice Monte Carlo simulations that
this observable has a sharp peak at the deconfinement transition, remains much
larger than the vacuum value for some range of $T>T_c$, and falls below the
vacuum value for $T > 2T_c$. This result suggests that long electric flux tubes
may persist for a finite range of temperatures past the deconfinement
transition, and at some stage disappear, presumably melting into a plasma of
gluons. As a side remark, we point out that our results at $T<T_c$ imply that
the eigenvalues of ordinary Polyakov loop holonomies in the confinement phase
have a slight tendency to attract rather than repel, which may be relevant to
certain models of confinement.Comment: 6 pages, 4 figure

### Properties of new unflavored mesons below 2.4 GeV

The global features of spectrum of highly excited light nonstrange mesons can
be well understood within both chiral symmetry restoration scenario combined
with the relation $M^2\sim J+n$ and within nonrelativistic description based on
the relation $M^2\sim L+n$. The predictions of these two alternative
classifications for missing states are different and only future experiments
can distinguish between the two. We elaborate and compare systematically the
predictions of both schemes, which may serve as a suggestion for future
experiments devoted to the search for missing states.Comment: 5 pages, to appear in Phys. Rev. C XX, 005200 (2007

### Stable Non-BPS States in F- theory

F-theory on K3 admits non-BPS states that are represented as string junctions extending between 7-branes. We classify the non-BPS states which are guaranteed to be stable on account of charge conservation and the existence of a region of moduli space where the 7-branes supporting the junction can be isolated from the rest of the branes. We find three possibilities; the 7-brane configurations carrying: (i) the D_1 algebra representing a D7-brane near an orientifold O7-plane, whose stable non-BPS state was identified before, (ii) the exotic affine E_1 algebra, whose stable non-BPS state seems to be genuinely non-perturbative, and, (iii) the affine E_2 algebra representing a D7-brane near a pair of O7-planes. As a byproduct of our work we construct explicitly all 7-brane configurations that can be isolated in a K3. These include non-collapsible configurations of affine type

### Evolution of a black hole-inhabited brane close to reconnection

Last moments of a mini black hole escaping from a brane are studied. It is
argued that at the point of reconnection, where the piece of the brane attached
to the black hole separates from the rest, the worldsheet of the brane becomes
isotropic (light-like). The degenerate mode of evolution, with the worldsheet
isotropic everywhere, is investigated. In particular, it is shown that the
brane approaches the reconnection point from below if it reconnects within a
certain limit distance, and from above if it reconnects beyond that distance.
The rate of relaxation to the degenerate mode is established. If the dimension
of the brane is $p$, the nondegeneracy, measured by the determinant of the
relevant part of the induced metric tensor, falls down as (latitudinal
angle)$^{2(p - 1)}$.Comment: 20 pages, 4 figure

### Vortex-boson duality in four space-time dimensions

A continuum version of the vortex-boson duality in (3+1) dimensions is
formulated and its implications studied in the context of a pair Wigner crystal
in underdoped cuprate superconductors. The dual theory to a phase fluctuating
superconductor (or superfluid) is shown to be a theory of bosonic strings
interacting through a Kalb-Ramond rank-2 tensorial gauge field. String
condensation produces Higgs mass for the gauge field and the expected Wigner
crystal emerges as an interesting space-time analog of the Abrikosov lattice.Comment: 4 pages REVTeX; for related work and info visit
http://www.physics.ubc.ca/~fran

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