Stringy negative-tension branes and the second law of thermodynamics

TL;DR

This paper investigates negative-tension branes in string theory, demonstrating how they can avoid violating the second law of thermodynamics despite their negative energy properties.

Contribution

It identifies specific mechanisms by which negative energy objects in string theory evade classical thermodynamic violations, especially for orientifold planes and particular configurations.

Findings

Negative energy objects in string theory can be stable due to special boundary conditions.

Mechanisms are found that prevent violations of the second law for most orientifold planes.

Distinct mechanisms are identified for the O8-plane and the AdS soliton.

Abstract

Negative energy objects generally lead to instabilities and a number of other disturbing behaviors. In particular, negative energy fluxes lead to a breakdown of the classical area theorem for black hole horizons, which can lead to violations of the second law of thermodynamics. The negative energy objects that arise in string theory involve special boundary conditions which remove the perturbative instabilities. We show that they have additional special features which allow them to evade contradiction with the second law. We identify one mechanism which applies for most orientifold planes in string theory, and distinct mechanisms for the O8-plane and the AdS soliton.