Thermodynamics of Quantum Ultra-cold Neutron Gas under Gravity of The Earth

The stored ultra-cold neutrons have been developed. A high density ultra-cold neutron gas has been recently produced by using the nuclear spallation method. We investigate the thermodynamic properties of the quantum ultra-cold neutron gas in the Earth's gravitational field. We find that the quantum effects increase temperature dependence of the chemical potential and the internal energy in the low temperature region. The density distribution of quantum ultra-cold neutron gas is modified by the Earth's gravitational field.Comment: 7 pages, 4 figures, Submitted to Progress of Theoretical Physic

Description of 8Be as Deformed Gas-like Two-Alpha-Paricle States

In order to study non-zero spin excitations of the recently proposed alpha-cluster condensation in the self-conjugate 4n nuclei, spatial deformation is introduced into the model wave function of the alpha-cluster condensate. The rotational band states of 8Be are investigated as a first step of a test case for the study of the deformation of the alpha-cluster condensate. Calculations reproduce well the binding energy of the 0+ ground state and also the excitation energy of the 2+ state. Our 0+ wave function is found to be almost exactly equal to the 0+ wave function obtained by the generator coordinate method using Brink's 2 alpha wave function. The study shows that both the 0+ ground and 2+ excited states can be considered as having a gas-like (i.e. weakly bound) 2 alpha-cluster structure. As for the 0+ ground state, the change of the wave function, due to the introduction of the deformation, is found to be very small.Comment: 20 pages, 14 EPS figure

Investigation of 9{}^9Be from nonlocalized clustering concept

The nonlocalized aspect of clustering, which is a new concept for self-conjugate nuclei, is extended for the investigation of the N{\not=}Z nucleus ${}^9$Be. A modified version of the THSR (Tohsaki-Horiuchi-Schuck-R\"opke) wave function is introduced based on the container picture. It is found that the constructed negative-parity THSR wave function is very suitable for describing the cluster states of ${}^9$Be. Namely the nonlocalized clustering is shown to prevail in ${}^9$Be. The calculated binding energy and radius of ${}^9$Be are consistent with calculations in other models and with experimental values. The squared overlaps between the THSR wave function and the Brink+GCM wave function for the $3/2^-$ rotational band of ${}^9$Be are found to be near 96%. Furthermore, by showing the density distribution of the ground state of ${}^9$Be, the {\pi}-orbit structure is naturally reproduced by using this THSR wave function.Comment: 20 pages, 5 figure

Alpha-Particle Clustering in Nuclei and Four-Alpha-Particle Condensation in 16O

Low density states near the 3 and 4 breakup threshold in 12C and 16O, respectively, are discussed in terms of the -particle condensation. Calculations are performed in OCM(Orthogonality Condition Model) and THSR (Tohsaki- Horiuchi-Schuck-Röpke) approaches. The 0+2 state in 12C and the 0+6 state in 16O are shown to have dilute density structures and give strong enhancement of the occupation of the S-state c.o.m. orbital of the -particles. The 0+6 state in 16O has a large component of +12C(0+2 ) configuration, which is another reliable evidence of the state to be of 4 condensate nature. The possibility of the existence of -particle condensed states in heavier n nuclei is also discussed