Searcharxiv⌕ Search

arXiv subjects

Emil Martinec

Publications and source records attributed to Emil Martinec.

29 records · Page 2Linked to original sources
arXiv1998

AdS Dynamics from Conformal Field Theory

We explore the extent to which a local string theory dynamics in anti-de Sitter space can be determined from its proposed Conformal Field Theory (CFT) description. Free fields in the bulk are constructed from the CFT operators, but difficulties are encountered when one attempts to incorporate interactions. We also discuss general features of black hole dynamics as seen from the CFT perspective. In particular, we argue that the singularity of AdS_3 black holes is resolved in the CFT description.

hep-th↗
arXiv1998

Probing Matrix Black Holes

Black holes in matrix theory may consist of interacting clusters (correlated domains) which saturate the uncertainty principle. We show that this assumption qualitatively accounts for the thermodynamic properties of both charged and neutral black holes, and reproduces the asymptotic geometry seen by probes.

hep-th↗
arXiv1997

M-theory and N=2 Strings

N=2 heterotic strings may provide a window into the physics of M-theory radically different than that found via the other supersymmetric string theories. In addition to their supersymmetric structure, these strings carry a four-dimensional self-dual structure, and appear to be completely integrable systems with a stringy density of states. These lectures give an overview of N=2 heterotic strings, as well as a brief discussion of possible applications of both ordinary and heterotic N=2 strings to D-branes and matrix theory.

hep-th↗
arXiv1997

Matrix Black Holes

Four and five dimensional extremal black holes with nonzero entropy have simple presentations in M-theory as gravitational waves bound to configurations of intersecting M-branes. We discuss realizations of these objects in matrix models of M-theory, investigate the properties of zero-brane probes, and propose a measure of their internal density. A scenario for black hole dynamics is presented.

hep-th↗
arXiv1996

Geometrical Structures of M-Theory

N=(2,1) heterotic string theory provides clues about hidden structure in M-theory related to string duality; in effect it geometrizes some aspects of duality. The program whereby one may deduce this hidden structure is outlined, together with the results obtained to date. Speculations are made as to the eventual shape of the theory. Talk presented at Strings '96 (Santa Barbara, July 20-25, 1996).

hep-th↗
arXiv1996

Vacua of M-theory and N=2 strings

String and membrane dynamics may be unified into a theory of 2+2 dimensional self-dual world-volumes living in a 10+2 dimensional target space. Some of the vacua of this M-theory are described by the N=(2,1) heterotic string, whose target space theory describes the world-volume dynamics of 2+2 dimensional `M-branes'. All classes of string and membrane theories are realized as particular vacua of the N=(2,1) string: Type IIA/B strings and supermembranes arise in the standard moduli space of toroidal compactifications, while type ${\rm I}'$ and heterotic strings arise from a $\bf Z_2$ orbifold of the N=2 algebra. Yet another vacuum describes M-theory on a ${\bf T}^5/{\bf Z}_2$ orientifold, the type I string on $ {\bf T}^4$, and the six-dimensional self-dual string. We find that open membranes carry `Chan-Paton fields' on their boundaries, providing a common origin for gauge symmetries in M-theory. The world-volume interactions of M-brane fluctuations agree with those of Born-Infeld effective dynamics of the Dirichlet two-brane in the presence of a non-vanishing electromagnetic field on the brane.

hep-th↗
arXiv1995

String field theory in curved spacetime and the resolution of spacelike singularities

We attempt to understand the fate of spacelike gravitational singularities in string theory via the quantum stress tensor for string matter in a fixed background. We first approximate the singularity with a homogeneous anisotropic background and review the minisuperspace equations describing the evolution of the scale factors and the dilaton. We then review and discuss the behavior of large strings in such models. In a simple model which expands isotropically for a finite period of time we compute the number density of strings produced by quantum pair production and find that this number, and thus the stress tensor, becomes infinite when the Hubble volume of the expansion exceeds the string scale, in a manner reminiscent of the Hagedorn transition. Based on this calculation we argue that either the region near the singularity undergoes a phase transition when the density reaches the order of a string mass per string volume, or that the backreaction of the produced string matter dramatically modifies the geometry.

hep-th↗
arXiv1994

Spacelike Singularities and String Theory

An interpretation of spacelike singularities in string theory uses target space duality to relate the collapsing Schwarzschild geometry near the singularity to an inflationary cosmology in dual variables. An appealing picture thus results whereby gravitational collapse seeds the formation of a new universe.

hep-th↗
arXiv1993

The Light Cone in String Theory

The causal boundary of string propagation -- defined as the hypersurface in loop space bordering the timelike(spacelike) domains in which two successive measurements of the string field do(do not) interfere with one another -- is argued to be $0=\int dσ\bigl(δX(σ)\bigr)^2 = \sum_{\ell=-\infty}^\infty δx^μ_{-\ell}δx_{μ\ell}.$ Some possible consequences are discussed.

hep-th↗