Spatial correlation of two-dimensional Bosonic multi-mode condensates

TL;DR

This paper investigates the spatial coherence properties of two-dimensional Bosonic multi-mode condensates, revealing that superposition of modes affects coherence decay and that individual modes maintain higher coherence than the aggregate system.

Contribution

It demonstrates that multi-mode condensates' spatial coherence decay can differ from BKT theory predictions, emphasizing the role of mode superposition and individual mode behavior.

Findings

Superposition of modes reduces overall coherence.

Coherence decay in individual modes is slower than in the combined system.

Overall coherence decay can appear faster than BKT predictions.

Abstract

We studied the spatial coherence of a Bosonic two-dimensional multi-mode condensate both through measurements and simulations. It is shown that condensates with a constant spatial density must be described as the superposition of several quantized modes which reduces the overall coherence. In this case, the spatial coherence can appear to decay faster than allowed by the Berezinskii-Kosterlitz-Thouless (BKT) theory. However, we find through spectroscopic measurements that the individual modes show a slower decay of the spatial coherence than the overall system.