Asymptotic Flatness, Little String Theory, and Holography

TL;DR

This paper explores the holographic duality for asymptotically flat string theories, proposing that the dual resides at spacelike infinity and is defined on a Lorentzian spacetime, with insights from little string theory.

Contribution

It introduces a novel perspective on holography in flat spacetimes, relating the dual to a theory on a hyperboloid at spacelike infinity and clarifying conceptual issues through comparison with little string theory.

Findings

Computed boundary 2-point functions for scalar operators.

Established the dual theory resides on a Lorentzian spacetime at spacelike infinity.

Clarified conceptual issues by comparing with linear dilaton boundary conditions.

Abstract

We argue that any non-gravitational holographic dual to asymptotically flat string theory in $d$-dimensions naturally resides at spacelike infinity. Since spacelike infinity can be resovled as a $(d-1)$-dimensional timelike hyperboloid (i.e., as a copy of de Sitter space in $(d-1)$ dimensions), the dual theory is defined on a Lorentz signature spacetime. Conceptual issues regarding such a duality are clarified by comparison with linear dilaton boundary conditions, such as those dual to little string theory. We compute both time-ordered and Wightman boundary 2-point functions of operators dual to massive scalar fields in the asymptotically flat bulk.