# Relaxation dynamics in the merging of $N$ independent condensates

## TL;DR

This paper investigates the out-of-equilibrium relaxation dynamics of multiple independent condensates merged in a ring trap, revealing long-lived supercurrents and their scaling behavior, with insights into phase profile smoothening mechanisms.

## Contribution

It provides a detailed experimental and theoretical analysis of how multiple condensates merge and relax, highlighting the formation of supercurrents and their scaling with the number of condensates.

## Key findings

- Observation of long-lived supercurrents post-merging
- Scaling of winding number with the number of condensates
- Insights into phase profile smoothening mechanisms

## Abstract

Controlled quantum systems such as ultracold atoms can provide powerful platforms to study non-equilibrium dynamics of closed many-body quantum systems, especially since a complete theoretical description is generally challenging. In this Letter, we present a detailed study of the rich out-of-equilibrium dynamics of an adjustable number $N$ of uncorrelated condensates after connecting them in a ring-shaped optical trap. We observe the formation of long-lived supercurrents and confirm the scaling of their winding number with $N$ in agreement with the geodesic rule. Moreover, we provide insight into the microscopic mechanism that underlies the smoothening of the phase profile.