Related papers: Electromagnetic Strings: Complementarity between T…

We investigate the Hagedorn transitions of string networks with Y-junctions as may occur, for example, with (p,q) cosmic superstrings. In a simplified model with three different types of string, the partition function reduces to three…

We study the condensate phase dynamics in a low-temperature equilibrium gas of weakly interacting bosons, harmonically trapped and isolated from the environment. We find that at long times, much longer than the collision time between…

These are lecture notes for the 1992 Erice Workshop on String Quantum Gravity and Physics at the Planck Energy Scale. In this talk a review of earlier work on finite temperature strings was presented. Several topics were covered, including…

We have investigated the finite temperature systems of non-BPS D-branes and D-brane-anti-D-brane pairs in the previous papers. It has been shown that non-BPS D9-branes and D9-anti-D9 pairs become stable near the Hagedorn temperature on the…

We consider large-N confining gauge theories with a Hagedorn density of states. In such theories the potential between a pair of colour-singlet sources may diverge at a critical distance r_c = 1/ T_H. We consider, in particular, pure N=1…

This thesis concerns the study of high-temperature string theory on curved backgrounds, generalizing the notions of Hagedorn temperature and thermal scalar to general backgrounds. Chapter 2 contains a review on string thermodynamics in flat…

N=4 Super Yang-Mills theory supplies us with a non-Abelian 4D gauge theory with a meaningful perturbation expansion, both in the UV and in the IR. We calculate the free energy on a 3-sphere and observe a deconfinement transition for large N…

We give examples of modeling the string free energy whose behavior mimics that of QCD: a power-law at high temperature and an exponential decrease at low temperature. Although the effective description is in terms of strings, no limiting…

We study the spacetime decay to nothing in string theory and M-theory. First we recall a nonsupersymmetric version of heterotic M-theory, in which bubbles of nothing -- connecting the two E_8 boundaries by a throat -- are expected to be…

We illustrate the main points behind the computation of the gravitational wave spectrum originated from a phase in the early universe where the energy density is dominated by highly excited fundamental string degrees of freedom - a Hagedorn…

Using an effective theory for an ensemble of center vortices, we observe the area law fall-off in the continuum limit for the SU($2$) gauge group in three-dimensional Euclidean space-time. The string tension is obtained in terms of the…

An ensemble of short open strings in equilibrium with the heat bath provided by the Euclidean worldvolume of a stack of Dbranes undergoes a thermal phase transition to a long string phase. The transition temperature is just below the string…

On an unstable D-brane, the rolling of the tachyon away from the maximum of its potential is described by time-dependent solutions in string theory. Subsequent analysis leads to an understanding of physics around the tachyon vacuum in terms…

It has recently been argued that D-branes in bosonic string theory can be described as noncommutative solitons, outside whose core the tachyon is condensed to its ground state. We conjecture that, in addition, the local U(1) gauge symmetry…

We review recent progress in string cosmology, where string dualities are applied so as to obtain complete cosmological evolutions, free of any essential singularities. Two classes of models are analyzed. The first class consists of string…

The dual theory describing the 4D Coulomb gas of point-like magnetically charged objects, which confines closed electric strings, is considered. The respective generalization of the theory of confining strings to confining membranes is…

We consider the critical behavior for a string theory near the Hagedorn temperature. We use the factorization of the worldsheet to isolate the Hagedorn divergences at all genera. We show that the Hagedorn divergences can be resummed by…

Induced by the Hagedorn instability, weakly-coupled $U(N)$ gauge theories on a compact manifold exhibit a confinement/deconfinement phase transition in the large-$N$ limit. Recently we discover that the thermal entropy of a free theory on…

We conjecture chronology is protected in string theory due to the condensation of light winding strings near closed null curves. This condensation triggers a Hagedorn phase transition, whose end-point target space geometry should be…

We study the Hagedorn temperature $T_H$ of strongly coupled quantum field theories admitting a holographic string or M-theory description in various regimes and scenarios. In the first part of the paper we propose a ``thermal scalar''…