150 research outputs found
Thermodynamics of Spinning Branes and their Dual Field Theories
We present a general analysis of the thermodynamics of spinning black
p-branes of string and M-theory. This is carried out both for the
asymptotically-flat and near-horizon case, with emphasis on the latter. In
particular, we use the conjectured correspondence between the near-horizon
brane solutions and field theories with 16 supercharges in various dimensions
to describe the thermodynamic behavior of these field theories in the presence
of voltages under the R-symmetry. Boundaries of stability are computed for all
spinning branes both in the grand canonical and canonical ensemble, and the
effect of multiple angular momenta is considered. A recently proposed
regularization of the field theory is used to compute the corresponding
boundaries of stability at weak coupling. For the D2, D3, D4, M2 and M5-branes
the critical values of Omega/T in the weak and strong coupling limit are
remarkably close. Finally, we also show that for the spinning D3-brane the tree
level R^4 correction supports the conjecture of a smooth interpolating function
between the free energy at weak and strong coupling.Comment: 59 pages, JHEP class. Minor typos corrected, added remark on
positivity of temperature, Sec. 6.1 improved, references adde
Heterotic/Type-I Duality in D<10 Dimensions, Threshold Corrections and D-Instantons
We continue our study of heterotic/type-I duality in D<10 dimensions. We
consider the heterotic and type-I theories compactified on tori to lower
dimensions. We calculate the special (``BPS saturated'') F^4 and R^4 terms in
the effective one-loop heterotic action. These terms are expected to be
non-perturbatively exact for D>4.
The heterotic result is compared with the associated type-I result. In D<9
dimensions, the type-I theory has instanton corrections due to D1 instantons.
In D=8 we use heterotic-type I duality to give a simple prescription of the
D-instanton calculation on the type I side. We allow arbitrary Wilson lines and
show that the D1-instanton determinant is the affine character-valued elliptic
genus evaluated at the induced complex structure of the D1-brane world-volume.
The instanton result has an expansion in terms of Hecke operators that suggest
an interpretation in terms of an SO(N) matrix model of the D1-brane. The total
result can be written in terms of generalized prepotentials revealing an
underlying holomorphic structure.
In D<8 we calculate again the heterotic perturbative thresholds and show that
they agree with the D1-instanton calculation using the rules derived in D=8.Comment: Latex, 67 pages, 1 figur
Phase Structure of Non-Commutative Field Theories and Spinning Brane Bound States
General spinning brane bound states are constructed, along with their
near-horizon limits which are relevant as dual descriptions of non-commutative
field theories. For the spinning D-brane world volume theories with a B-field a
general analysis of the gauge coupling phase structure is given, exhibiting
various novel features, already at the level of zero angular momenta. We show
that the thermodynamics is equivalent to the commutative case at large N and we
discuss the possibility and consequences of finite N. As an application of the
general analysis, the range of validity of the thermodynamics for the NCSYM is
discussed. In view of the recently conjectured existence of a 7-dimensional
NCSYM, the thermodynamics of the spinning D6-brane theory, for which a stable
region can be found, is presented in detail. Corresponding results for the
spinning M5-M2 brane bound state, including the near-horizon limit and
thermodynamics, are given as well.Comment: 34 pages, JHEP class. minor corrections, final JHEP versio
Phases of Kaluza-Klein Black Holes: A Brief Review
We review the latest progress in understanding the phase structure of static
and neutral Kaluza-Klein black holes, i.e. static and neutral solutions of pure
gravity with an event horizon that asymptote to a d-dimensional Minkowski-space
times a circle. We start by reviewing the (mu,n) phase diagram and the split-up
of the phase structure into solutions with an internal SO(d-1) symmetry and
solutions with Kaluza-Klein bubbles. We then discuss the uniform black string,
non-uniform black string and localized black hole phases, and how those three
phases are connected, involving issues such as classical instability and
horizon-topology changing transitions. Finally, we review the bubble-black hole
sequences, their place in the phase structure and interesting aspects such as
the continuously infinite non-uniqueness of solutions for a given mass and
relative tension.Comment: 23 pages, 5 figures. v2: Typo fixe
Semi-Classical Blocks and Correlators in Rational and Irrational Conformal Field Theory
The generalized Knizhnik-Zamolodchikov equations of irrational conformal
field theory provide a uniform description of rational and irrational conformal
field theory. Starting from the known high-level solution of these equations,
we first construct the high-level conformal blocks and correlators of all the
affine-Sugawara and coset constructions on simple g. Using intuition gained
from these cases, we then identify a simple class of irrational processes whose
high-level blocks and correlators we are also able to construct.Comment: 53 pages, Latex. Revised version with extended discussion of phases
and secondarie
Solving the Ward Identities of Irrational Conformal Field Theory
The affine-Virasoro Ward identities are a system of non-linear differential
equations which describe the correlators of all affine-Virasoro constructions,
including rational and irrational conformal field theory. We study the Ward
identities in some detail, with several central results. First, we solve for
the correlators of the affine-Sugawara nests, which are associated to the
nested subgroups . We also find an
equivalent algebraic formulation which allows us to find global solutions
across the set of all affine-Virasoro constructions. A particular global
solution is discussed which gives the correct nest correlators, exhibits
braiding for all affine-Virasoro correlators, and shows good physical behavior,
at least for four-point correlators at high level on simple . In rational
and irrational conformal field theory, the high-level fusion rules of the
broken affine modules follow the Clebsch-Gordan coefficients of the
representations.Comment: 45 pages, Latex, UCB-PTH-93/18, LBL-34111, BONN-HE-93/17. We
factorize the biconformal nest correlators of the first version, obtaining
the conformal correlators of the affine-Sugawara nests on g/h_1/.../h_
Ward Identities for Affine-Virasoro Correlators
Generalizing the Knizhnik-Zamolodchikov equations, we derive a hierarchy of
non-linear Ward identities for affine-Virasoro correlators. The hierarchy
follows from null states of the Knizhnik-Zamolodchikov type and the assumption
of factorization, whose consistency we verify at an abstract level. Solution of
the equations requires concrete factorization ans\"atze, which may vary over
affine-Virasoro space. As a first example, we solve the non-linear equations
for the coset constructions, using a matrix factorization. The resulting coset
correlators satisfy first-order linear partial differential equations whose
solutions are the coset blocks defined by Douglas.Comment: 53 pages, Latex, LBL-32619, UCB-PTH-92/24, BONN-HE-92/2
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