36 research outputs found
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 Be 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 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 Be. Namely
the nonlocalized clustering is shown to prevail in Be. The calculated
binding energy and radius of 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 rotational band of
Be are found to be near 96%. Furthermore, by showing the density
distribution of the ground state of 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