Logarithmic Unification From Symmetries Enhanced in the Sub-Millimeter Infrared

TL;DR

This paper proposes that in theories with TeV-scale strings and extra dimensions, gauge coupling unification can occur through geometric symmetries at large distances, challenging traditional short-distance symmetry restoration views.

Contribution

It introduces a novel mechanism for logarithmic gauge unification based on large-distance geometric symmetries in extra-dimensional theories.

Findings

Logarithmic unification possible in TeV-scale string theories.

Unification arises from classical field variations in large transverse dimensions.

Constructs with supersymmetric D-branes demonstrate the proposed unification mechanism.

Abstract

In theories with TeV string scale and sub-millimeter extra dimensions the attractive picture of logarithmic gauge coupling unification at $10^{16}$ GeV is seemingly destroyed. In this paper we argue to the contrary that logarithmic unification {\it can} occur in such theories. The rationale for unification is no longer that a gauge symmetry is restored at short distances, but rather that a geometric symmetry is restored at large distances in the bulk away from our 3-brane. The apparent `running' of the gauge couplings to energies far above the string scale actually arises from the logarithmic variation of classical fields in (sets of) two large transverse dimensions. We present a number of N=2 and N=1 supersymmetric D-brane constructions illustrating this picture for unification.