Spin distribution of nuclear levels using static path approximation with random-phase approximation

Abstract

We present a thermal and quantum-mechanical treatment of nuclear rotation using the formalism of static path approximation (SPA) plus random-phase approximation (RPA). Naive perturbation theory fails because of the presence of zero-frequency modes due to dynamical symmetry breaking. Such modes lead to infrared divergences. We show that composite zero-frequency excitations are properly treated within the collective coordinate method. The resulting perturbation theory is free from infrared divergences. Without the assumption of individual random spin vectors, we derive microscopically the spin distribution of the level density. The moment of inertia is thereby related to the spin-cutoff parameter in the usual way. Explicit calculations are performed for 56^Fe; various thermal properties are discussed. In particular, we demonstrate that the increase of the moment of inertia with increasing temperature is correlated with the suppression of pairing correlations.

12 pages, 8 figures, accepted for publication in Physical Review C

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Cited by in corpus (4)

• Thermodynamic Properties of ${}^{56,57}$Fe
• Thermodynamic properties of hot nuclei within the self-consistent quasiparticle random-phase approximation
• State densities of heavy nuclei in the static-path plus random-phase approximation
• Level density of the $sd$-nuclei $-$ statistical shell-model predictions