Geometric and Renormalized Entropy in Conformal Field Theory

In statistical physics, useful notions of entropy are defined with respect to some coarse graining procedure over a microscopic model. Here we consider some special problems that arise when the microscopic model is taken to be relativistic quantum field theory. These problems are associated with the existence of an infinite number of degrees of freedom per unit volume. Because of these the microscopic entropy can, and typically does, diverge for sharply localized states. However the difference in the entropy between two such states is better behaved, and for most purposes it is the useful quantity to consider. In particular, a renormalized entropy can be defined as the entropy relative to the ground state. We make these remarks quantitative and precise in a simple model situation: the states of a conformal quantum field theory excited by a moving mirror. From this work, we attempt to draw some lessons concerning the ``information problem'' in black hole physicsComment: 35 pages, 4 figures available on request to [email protected], use Phyzzx, PUPT-1454, IASSNS-HEP 93/8

Correspondence principle in quantum gravity

The problem of consistent formulation of the correspondence principle in quantum gravity is considered. The usual approach based on the use of the two-particle scattering amplitudes is shown to be in disagreement with the classical result of General Relativity given by the Schwarzschild solution. It is shown also that this approach fails to describe whatever non-Newtonian interactions of macroscopic bodies. An alternative interpretation of the correspondence principle is given directly in terms of the effective action. Gauge independence of the \hbar^0 part of the one-loop radiative corrections to the gravitational form factors of the scalar particle is proved, justifying the interpretation proposed. Application to the black holes is discussed.Comment: Talk presented at the international meeting "Quantum Gravity and Spectral Geometry", Naples, July 2001. 4 pages, 1 figur

D-branes and Fat Black Holes

The application of D-brane methods to large black holes whose Schwarzschild radius is larger than the compactification scale is problematic. Callan and Maldacena have suggested that despite apparent problems of strong interactions when the number of branes becomes large, the open string degrees of freedom may remain very dilute due to the growth of the horizon area which they claim grows more rapidly than the average number of open strings. Such a picture of a dilute weakly coupled string system conflicts with the picture of a dense string-soup that saturates the bound of one string per planck area. A more careful analysis shows that Callan and Maldacena were not fully consistent in their estimates. In the form that their model was studied it can not be used to extrapolate to large mass without being in conflict with the Hawking Bekenstein entropy formula. A somewhat modified model can reproduce the correct entropy formula. In this ``improved model" the number of string bits on the horizon scales like the entropy in agreement with earlier speculations of Susskind.Comment: 12 pages, uses phyzz

Introduction

Multistable figures offer an intriguing model for arbitrating conflicting positions. Moving back and forth between the different aspects under which something can be seen, one recognizes that mutually contradictory descriptions can be equally valid and that disputes over the correct account can be resolved without dissolving differences or establishing a higher synthesis. Yet, the experience of a gestalt switch also offers a model for radical conversions and revolutions – that is, for irreversible leaps to incommensurable alternatives foiling ideals of rational choice while providing the possibility and necessity of decision. Accentuating the temporal dimensions of multistable figures, this multidisciplinary volume illuminates the critical potentials and limits of multistability as a complex figure of thought

Preface

Tension/Spannung explores the critical potential of tension by bringing together contributions from several academic and artistic fields, including history of science, philosophy, literature and media studies, political and social theory, visual and performing arts. Both individually and in their combination, they produce a rapprochement and confrontation between different meanings and models of tension that unsettle the apparent self-evidence that any particular model has when considered in an isolated context

‘La vera Diversità’:Multistability, Circularity, and Abjection in Pasolini’s Pilade

Before completing his uncharacteristically hopeful filmic vision of an African Oresteia, Pier Paolo Pasolini invented a theatrical continuation of Aeschylus’s trilogy. Pilade (1966/70) imagines what happens after Orestes, having being absolved by the Aeropagos in Athens, goes back to Argos. With its clear allusions to political developments in the last century – fascism, the Resistance, and Communist revolutions – the play reads as a mythical allegory for the situation of engaged intellectuals in the twentieth century

Fermions in a Global Monopole Background

We study the scattering of fermions in a ``global monopole'' background metric. This is the four-dimensional analogue of the scattering on a cone in three dimensions. The scattering amplitude is exactly obtained. We then study massless fermion-dyon systems in such a background metric. The density of the $S$-wave fermion condensate is found to be given by a constant times the flat space value of Callan and Rubakov.Comment: CU-TP-618, 9 pages. (minor changes

Oscillations and Incommensurable Decisions:On the Multistable Use of Multistable Figures

The children’s book Duck! Rabbit! dramatizes the lesson that just because one is right, others don’t have to be wrong. An endless dispute is quickly settled once the quarrellers experience an aspect change or gestalt switch and thereby realize that the same picture can be seen in different ways. This simple scenario offers an intriguing model for arbitrating between conflicting positions by going back and forth between different aspects and thereby realizing that conflicting accounts can be equally valid

Tension In/Between Aesthetics, Politics, and Physics

The article sketches a critical paradigm for interdisciplinary work that is centred on tension as a highly ambiguous and ultimately deeply paradoxical notion. It highlights that a unifying account of what tension is or a systematic classification of its diverse meanings would risk resolving tensions between different approaches and privileging a particular mode of doing so. Successively focussing on aesthetic, socio-political, and physical tensions, the essay articulates tension rather as a broad umbrella term that is stretched by multi-perspectival articulations, unified through its intensive surface tension, and at the same time full of transformative and generative potentials. In particular, it proposes that tensions between different cultural or disciplinary fields can be made productive by inducing tensions within each field so that different fields can be related to each other on the basis of tension rather than some substantial commonality