Willy Fischler

The Operator product expansion for Wilson loops and surfaces in the large N limit

The operator product expansion for {open_quotes}small{close_quotes} Wilson loops in N=4, d=4 SYM theory is studied. The OPE coefficients are calculated in the large {ital N} and g{sub YM}{sup 2}N limit by exploiting the AdS-CFT correspondence. We also consider Wilson surfaces in the (0,2), d=6 superconformal theory. In this case, we find that the UV divergent terms include a term proportional to the rigid string action. {copyright} {ital 1999} {ital The American Physical Society}

Constraints on the Baryogenesis Scale from Neutrino Masses

Over the past few years it has been realized1 that at temperatures above ~m w/αw transitions that violate baryon (B) and lepton (L) number occur rapidly since, due to the electroweak anomaly, these quantum numbers are not conserved. Indeed,

Schwarzschild Black Holes from Matrix Theory

\begin{array}{*{20}{c}} {{\partial _\mu }j_\mu ^B = \frac{{g_2^2}}{{32{\pi ^2}}}{n_f}(\frac{1}{3}x3)F_{\mu v}^a\tilde F_a^{\mu v}} \\ {{\partial _\mu }j_\mu ^L = \frac{{g_2^2}}{{32{\pi ^2}}}{n_f}F_{\mu v}^a\tilde F_a^{\mu v}} \\ {{\partial _\mu }j_\mu ^{B - L} = 0.} \end{array}

Schwarzschild black holes in Matrix theory II

Recent astronomical observations indicate that the universe is accelerating. We argue that generic quintessence models that accommodate the present day acceleration tend to accelerate eternally. As a consequence the resulting spacetimes exhibit event horizons. Hence, quintessence poses the same problems for string theory as asymptotic de Sitter spaces.Recent astronomical observations indicate that the universe is acceler- ating. We argue that generic quintessence models that accomodate the present day acceleration tend to accelerate eternally. As a consequence the resulting spacetimes exhibit event horizons. Hence, quintessence poses the same problems for string theory as asymptotic de Sitter spaces.

Strongly Coupled Gauge Theories: High and Low Temperature Behavior of Non-local Observables

We consider Matrix theory compactified on T^3 and show that it correctly describes the properties of Schwarzschild black holes in 7+1 dimensions, including the energy-entropy relation, the Hawking temperature and the physical size, up to numerical factors of order unity. The most economical description involves setting the cut-off N in the discretized light-cone quantization to be of order the black hole entropy. A crucial ingredient necessary for our work is the recently proposed equation of state for 3+1 dimensional SYM theory with 16 supercharges. We give detailed arguments for the range of validity of this equation following the methods of Horowitz and Polchinski.

Dark Radiation Emerging After Big Bang Nucleosynthesis

Abstract Most supersymmetric models possess a decoupled particle with mass of order M W which is copiously produced in the early universe and whose decays produce huge amounts of entropy. We show how this problem is avoided in theories in which the hidden sector contains several light fields.

Evidence for winding states in noncommutative quantum field theory

The idea that asymptotic de Sitter space can be described by a finite Hilbert Space implies that any quantum measurement has an irreducible innacuracy. We argue that this prevents any measurement from verifying the existence of the Poincare recurrences that occur in the mathematical formulation of quantum de Sitter (dS) space. It also implies that the mathematical quantum theory of dS space is not unique. There will be many different hamiltonians, which give the same results, within the uncertainty in all possible measurements.