Modulation Spectroscopy and Dynamics of Double Occupancies in a Fermionic Mott Insulator

TL;DR

This paper investigates how modulation spectroscopy reveals the creation of double occupancies in a 3D Fermionic Mott insulator, showing temperature-dependent features linked to magnetic order and quasiparticle excitations.

Contribution

It provides a theoretical analysis of doublon creation rates under lattice modulation, connecting spectral features to magnetic order and quasiparticle dynamics in the system.

Findings

High-temperature broad response peaked at Hubbard U

Low-temperature coherent peak indicating antiferromagnetic order

Oscillations in doublon creation rate as a function of modulation frequency

Abstract

We calculate the rate of creation of double occupancies in a 3D Fermionic Mott insulator near half-filling by modulation of optical lattice potential. At high temperatures, incoherent holes lead to a broad response peaked at the Hubbard repulsion $U$. At low temperatures, antiferromagnetic order leads to a coherent peak for the hole along with broad features representing spin wave shake-off processes. This is manifested in the doublon creation rate as a sharp absorption edge and oscillations as a function of modulating frequency. Thus, modulation spectroscopy can be used as a probe of antiferromagnetic order and nature of quasiparticle excitations in the system.