Doublon relaxation in the Bose-Hubbard model

TL;DR

This paper investigates the decay dynamics of doublons in the Bose-Hubbard model, revealing that their relaxation time can be exponentially long and can be exactly calculated under certain conditions using a quasiclassical approach.

Contribution

The paper introduces an exact evaluation method for doublon decay exponents in the Bose-Hubbard model at low occupation numbers using a novel quasiclassical technique.

Findings

Doublon relaxation time is exponentially long.

Exact calculation of decay exponents is possible at low occupation.

Developed a quasiclassical approach for high-order decay amplitudes.

Abstract

Decay of a high-energy double occupancy state, doublon, in a narrow-band lattice requires creation of a coherent many-particle excitation. This leads to an exponentially long relaxation time of such a state. We show that, if the average occupation number is sufficiently small, the corresponding exponent may be evaluated exactly. To this end we develop the quasiclassical approach to calculation of the high-order tree-level decay amplitudes.