# Probing the bond order wave phase transitions of the ionic Hubbard model by superlattice modulation spectroscopy

## TL;DR

This paper proposes using superlattice modulation spectroscopy to detect the elusive bond order wave phase in the ionic Hubbard model, leveraging advanced computational methods to identify phase transition signatures.

## Contribution

It introduces a novel spectroscopic detection scheme for the bond order wave phase in the ionic Hubbard model, supported by theoretical analysis and simulations.

## Key findings

- Spectroscopy reveals characteristics of phase transitions indicating the bond order wave.
- The approach distinguishes between band and Mott insulators.
- Insights into excitation spectra of different insulating phases.

## Abstract

An exotic phase, the bond order wave, characterized by the spontaneous dimerization of the hopping, has been predicted to exist sandwiched between the band and Mott insulators in systems described by the ionic Hubbard model. Despite growing theoretical evidences, this phase still evades experimental detection. Given the recent realization of the ionic Hubbard model in ultracold atomic gases, we propose here to detect the bond order wave using superlattice modulation spectroscopy. We demonstrate, with the help of time-dependent density-matrix renormalization group and bosonization, that this spectroscopic approach reveals characteristics of both the Ising and Kosterlitz-Thouless transitions signaling the presence of the bond order wave phase. This scheme also provides insights into the excitation spectra of both the band and Mott insulators.