A Matrix Model for Misner Universe and Closed String Tachyons

TL;DR

This paper employs D-instantons to analyze Misner universe, revealing how closed string tachyons resolve singularities, induce non-commutative fuzzy regions, and suggest a holographic, matrix-based model for cosmological big bang/big crunch transitions.

Contribution

It introduces a matrix model approach using D-instantons to describe Misner universe and demonstrates how tachyon condensation resolves singularities and connects past and future.

Findings

Closed string tachyons remove spacelike singularities.

Near the singularity, space and time become non-commutative.

The model provides a holographic, matrix-based description of cosmological transitions.

Abstract

We use D-instantons to probe the geometry of Misner universe, and calculate the world volume field theory action, which is of the 1+0 dimensional form and highly non-local. Turning on closed string tachyons, we see from the deformed moduli space of the D-instantons that the spacelike singularity is removed and the region near the singularity becomes a fuzzy cone, where space and time do not commute. When realized cosmologically there can be controllable trans-planckian effects. And the infinite past is now causally connected with the infinite future, thus also providing a model for big crunch/big bang transition. In the spirit of IKKT matrix theory, we propose that the D-instanton action here provides a holographic description for Misner universe and time is generated dynamically. In addition we show that winding string production from the vacua and instability of D-branes have simple uniform interpretations in this second quantized formalism.