Spectral statistics of a spin-12 particle in coupled quartic oscillator potentials

The quantum spectral statistical properties, i.e. the nearest neighbor level spacing distribution (NNSD) and the mode fluctuation distribution of a spin-View the MathML source particle in three-dimensional coupled quartic oscillator potentials are numerically studied. Introducing the coupling terms, the system can be continuously transformed from an integrable to chaotic one. With use of three parameter sets, three kinds of the Gaussian ensembles can be realized. The Brody-like NNSD interpolation formula between the Poisson distribution and that of each ensemble is found to work well for the numerically obtained NNSD.