Classical bifurcation in a quadrupolar NMR system

TL;DR

This paper demonstrates classical bifurcation in a quadrupolar NMR system using the Josephson Junction model, showing symmetry breaking and coexistence of linear and nonlinear regimes in a spin ensemble.

Contribution

It experimentally confirms bifurcation in a quadrupolar NMR system, extending the analogy to a symmetric two-mode Bose--Einstein condensate.

Findings

Bifurcation occurs independently of spin value and physical system.

Experimental validation of bifurcation in quadrupolar nuclei.

Quadrupolar NMR system modeled as a two-mode Bose--Einstein condensate.

Abstract

The Josephson Junction model is applied to the experimental implementation of classical bifurcation in a quadrupolar Nuclear Magnetic Resonance system. There are two regimes, one linear and one nonlinear which are implemented by the radio-frequency term and the quadrupolar term of the Hamiltonian of a spin system respectively. Those terms provide an explanation of the symmetry breaking due to bifurcation. Bifurcation depends on the coexistence of both regimes at the same time in different proportions. The experiment is performed on a lyotropic liquid crystal sample of an ordered ensemble of $^{133}$Cs nuclei with spin $I=7/2$ at room temperature. Our experimental results confirm that bifurcation happens independently of the spin value and of the physical system. With this experimental spin scenario, we confirm that a quadrupolar nuclei system could be described analogously to a symmetric two--mode Bose--Einstein condensate.