GHZ-like states in the Qubit-Qudit Rabi Model

TL;DR

This paper investigates a qubit-qudit Rabi model, revealing that multilevel qudits enhance interactions, produce GHZ-type ground states, and offer pathways for entanglement control and state preparation.

Contribution

It introduces a detailed analysis of a qubit-qudit Rabi model, highlighting the emergence of GHZ-like ground states and dynamics under quenching and adiabatic processes.

Findings

Ground state is GHZ-like entangled state.

Qudit multilevels enhance qubit-qudit interactions.

Photon generation is increased with qudit levels during quenching.

Abstract

We study a Rabi type Hamiltonian system in which a qubit and a d-level quantum system (qudit) are coupled through a common resonator. In the weak and strong coupling limits the spectrum is analysed through suitable perturbative schemes. The analysis show that the presence of the multilevels of the qudit effectively enhance the qubit-qudit interaction. The ground state of the strongly coupled system is a found of Greenberger-Horne-Zeilinger (GHZ) type. Therefore, despite the qubit-qudit strong coupling, the nature of the specific tripartite entanglement of the GHZ state suppress the bipartite entanglement. We analyze the system dynamics under quenching and adiabatic switching of the qubit-resonator and qudit-resonator couplings. In the quench case, we found that the non-adiabatic generations of photons in the resonator is enhanced by the number of levels in the qudit. The adiabatic control represents a possible route for preparation of GHZ states. Our analysis provides relevant information for future studies on coherent state transfer in qubit-qudit systems.