Superposition states of ultracold bosons in rotating rings with a realistic potential barrier

TL;DR

This paper investigates how superposition states of ultracold bosons in rotating rings depend on interaction strength and barrier properties, revealing a trade-off between energy gap size and superposition quality, especially with realistic finite-width barriers.

Contribution

It provides a detailed analysis of superposition states in rotating-ring lattices beyond idealized models, considering realistic barrier potentials and their impact on energy gaps and state quality.

Findings

Energy gap decreases exponentially with particle number for finite-width barriers.

Trade-off identified between large energy gaps and high superposition quality.

Finite barrier width significantly affects superposition state stability.

Abstract

In a recent paper [Phys. Rev. A 82, 063623 (2010)] Hallwood et al. argued that it is feasible to create large superposition states with strongly interacting bosons in rotating rings. Here we investigate in detail how the superposition states in rotating-ring lattices depend on interaction strength and barrier height. With respect to the latter we find a trade-off between large energy gaps and high cat quality. Most importantly, we go beyond the \delta-function approximation for the barrier potential and show that the energy gap decreases exponentially with the number of particles for weak barrier potentials of finite width. These are crucial issues in the design of experiments to realize superposition states.