On Supergravity Solutions of Branes in Melvin Universes

TL;DR

This paper constructs supergravity solutions for branes in Melvin universes, revealing non-commutative field theories with variable non-commutativity and a critical length scale, with potential cosmological implications.

Contribution

It introduces new supergravity solutions for branes in Melvin backgrounds, describing non-constant non-commutative field theories and analyzing their properties.

Findings

Existence of a critical length scale for non-commutative effects.

Non-supersymmetric non-commutative theories with variable parameters.

Connections between M5-branes in Melvin universes and lower-dimensional theories.

Abstract

We study supergravity solutions of type II branes wrapping a Melvin universe. These solutions provide the gravity description of non-commutative field theories with non-constant non-commutative parameter. Typically these theories are non-supersymmetric, though they exhibit some feature of their corresponding supersymmetric theories. An interesting feature of these non-commutative theories is that there is a critical length in the theory in which for distances larger than this length the effects of non-commutativity become important and for smaller distances these effects are negligible. Therefore we would expect to see this kind of non-commutativity in large distances which might be relevant in cosmology. We also study M5-brane wrapping on 11-dimensional Melvin universe and its descendant theories upon compactifying on a circle.