Thermal properties of a rotating nucleus in a fluctuating mean field approach

Abstract

The static path approximation to the path integral representation of partition function provides a natural microscopic basis to deal with thermal fluctuations around mean field configurations. Using this approach for one-dimensional cranking Hamiltonian with quadrupole- quadrupole interaction term we have studied a few properties like energy, level density, level density parameter($a$) and moment of inertia as a function of temperature and spin for $^{64}Zn$ taking it as an illustrative example. We have also investigated the effects of variation in interaction strength on the level density and the parameter $a$ as a function of temperature. The moment of inertia, $\cal I$ versus rotational frequency, $\omega$ plot shows a sudden rise in the value of $\cal I$ due to rotation alignment of $0g_{9/2}$ orbitals at $\omega\approx 1.0$ MeV for a small temperature T $\sim 0.5$ MeV. At high T $\sim$ 2.0 MeV about 40-45$\%$ of each angular momentum is generated by alignment of $0g_{9/2}$ orbitals with an interesting result that at $\omega\sim 1.0$ MeV and spin J $\sim$ 16 the moment of inertia has almost a constant, temperature independent value.