Time evolution of the one-dimensional Jaynes-Cummings-Hubbard Hamiltonian

TL;DR

This paper analytically studies the time evolution of single excitations in a one-dimensional Jaynes-Cummings-Hubbard system, revealing unusual propagation behaviors and connections to spin chain models.

Contribution

It provides an exact diagonalization approach to analyze excitation dynamics in the JCH system with uniform and parabolic couplings, uncovering novel propagation phenomena.

Findings

Slower than expected excitation propagation.

Splitting of excitations into two pulses traveling at different speeds.

JCH system mimics two Heisenberg spin chains under certain conditions.

Abstract

The Jaynes-Cummings-Hubbard (JCH) system describes a network of single-mode photonic cavities connected via evanescent coupling. Each cavity contains a single two level system which can be tuned in resonance with the cavity. Here we explore the behavior of single excitations (where an excitation can be either photonic or atomic) in the linear JCH system, which describes a coupled cavity waveguide. We use direct, analytic diagonalization of the Hamiltonian to study cases where inter-cavity coupling is either uniform or varies parabolically along the chain. Both excitations located in a single cavity, as well as one excitation as a Gaussian pulse spread over many cavities, are investigated as initial states. We predict unusual behavior of this system in the time domain, including slower than expected propagation of the excitation, and also splitting of the excitation into two distinct pulses, which travel at distinct speeds. In certain limits, we show that the JCH system mimics two Heisenberg spin chains.