# Twofold correlation spreading in a strongly correlated lattice Bose gas

## TL;DR

This paper investigates how correlations spread in a lattice Bose gas, revealing a universal twofold cone structure with two distinct velocities in both superfluid and Mott-insulator phases, providing insights into the excitation spectrum.

## Contribution

It demonstrates the universal twofold correlation spreading in a strongly correlated Bose-Hubbard chain using advanced numerical methods.

## Key findings

- Identification of a twofold cone structure in correlation spreading
- Distinct velocities related to microscopic properties
- Implications for experimental observations

## Abstract

We study the spreading of correlations in the Bose-Hubbard chain, using the time-dependent matrix-product state approach. In both the superfluid and the Mott-insulator phases, we find that the time-dependent correlation functions generally display a universal twofold cone structure characterized by two distinct velocities. The latter are related to different microscopic properties of the system and provide useful information on the excitation spectrum. The twofold spreading of correlations has profound implications on experimental observations that are discussed.