Quantum phase transition in an atom-molecule conversion system with atomic hopping

TL;DR

This paper investigates quantum phase transitions in an atom-molecule system with atomic hopping, revealing how phase boundaries depend on hopping strength and detuning, and demonstrating control over phase transitions via atomic hopping.

Contribution

It provides a comprehensive analysis combining mean field and full quantum methods, showing the phase boundary's dependence on system parameters and finite-size effects.

Findings

Phase boundary depends on atomic hopping strength and detuning.

Quantum phase transition can be controlled by atomic hopping.

Finite-size scaling confirms phase boundary consistency in large systems.

Abstract

The quantum phase transition in an atom-molecule conversion system with atomic hopping between different hyperfine states is studied. In mean field approximation, we give the phase diagram whose phase boundary only depends on the atomic hopping strength and the atom-molecule energy detuning but not on the atomic interaction. Such a phase boundary is further confirmed by the fidelity of the ground state and the energy gap between the first-excited state and the ground one. In comparison to mean field approximation, we also study the quantum phase transition in full quantum method, where the phase boundary can be affected by the particle number of the system. Whereas, with the help of finite-size scaling behaviors of energy gap, fidelity susceptibility and the first-order derivative of entanglement entropy, we show that one can obtain the same phase boundary by the MFA and full quantum methods in the limit of $N\rightarrow \infty$. Additionally, our results show that the quantum phase transition can happens at the critical value of the atomic hopping strength even if the atom-molecule energy detuning is fixed on a certain value, which provides one a new way to control the quantum phase transition.