3,162 research outputs found
Analysis of previous microscopic calculations for second state in C in terms of 3-alpha particle Bose-condensed state
The wave function of the second state of C which was obtained
long time ago by solving the microscopic 3 problem is shown to be
almost completely equivalent to the wave function of the 3 condensed
state which has been proposed recently by the present authors. This equivalence
of the wave functions is shown to hold in two cases where different effective
two-nucleon forces are adopted. This finding gives strong support for
interpreting the second state of C which is the key state for the
synthesis of C in stars ('Hoyle' state), and which is one of the typical
mysterious states in light nuclei, as a gas-like structure of three
particles, Bose-condensed into an identical s-wave function.Comment: revtex, 5 pages, 2 figures, submitted to Phys. Rev.
Alpha cluster condensation in 12C and 16O
A new -cluster wave function is proposed which is of the
-particle condensate type. Applications to C and O show
that states of low density close to the 3 resp. 4 -particle threshold
in both nuclei are possibly of this kind. It is conjectured that all
self-conjugate 4 nuclei may show similar features.Comment: 4 pages, 2 tables, 2 figure
Trapping of Neutral Rubidium with a Macroscopic Three-Phase Electric Trap
We trap neutral ground-state rubidium atoms in a macroscopic trap based on
purely electric fields. For this, three electrostatic field configurations are
alternated in a periodic manner. The rubidium is precooled in a magneto-optical
trap, transferred into a magnetic trap and then translated into the electric
trap. The electric trap consists of six rod-shaped electrodes in cubic
arrangement, giving ample optical access. Up to 10^5 atoms have been trapped
with an initial temperature of around 20 microkelvin in the three-phase
electric trap. The observations are in good agreement with detailed numerical
simulations.Comment: 4 pages, 4 figure
Restoration of Isospin Symmetry in Highly Excited Nuclei
Explicit relations between the isospin mixing probability, the spreading
width of the Isobaric Analog State (IAS) and the
statistical decay width of the compound nucleus at finite excitation
energy, are derived by using the Feshbach projection formalism. The temperature
dependence of the isospin mixing probability is discussed quantitatively for
the first time by using the values of and of
calculated by means of microscopic models. It is shown that the
mixing probability remains essentially constant up to a temperature of the
order of 1 MeV and then decreases to about 1/4 of its zero temperature value,
at higher temperature than 3 MeV, due to the short decay time of the
compound system.Comment: 13 pages, 1 figure (PostScript file included). To appear in Phys.
Lett.
Accuracy of B(E2; 0+ -> 2+) transition rates from intermediate-energy Coulomb excitation experiments
The method of intermediate-energy Coulomb excitation has been widely used to
determine absolute B(E2; 0+ -> 2+) quadrupole excitation strengths in exotic
nuclei with even numbers of protons and neutrons. Transition rates measured
with intermediate-energy Coulomb excitation are compared to their respective
adopted values and for the example of 26Mg to the B(E2; 0+ -> 2+) values
obtained with a variety of standard methods. Intermediate-energy Coulomb
excitation is found to have an accuracy comparable to those of long-established
experimental techniques.Comment: to be published in Phys. Rev.
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