13,863 research outputs found
Mathematical Structure of Rabi Oscillations in the Strong Coupling Regime
In this paper we generalize the Jaynes--Cummings Hamiltonian by making use of
some operators based on Lie algebras su(1,1) and su(2), and study a
mathematical structure of Rabi floppings of these models in the strong coupling
regime. We show that Rabi frequencies are given by matrix elements of
generalized coherent operators (quant--ph/0202081) under the rotating--wave
approximation.
In the first half we make a general review of coherent operators and
generalized coherent ones based on Lie algebras su(1,1) and su(2). In the
latter half we carry out a detailed examination of Frasca (quant--ph/0111134)
and generalize his method, and moreover present some related problems.
We also apply our results to the construction of controlled unitary gates in
Quantum Computation. Lastly we make a brief comment on application to Holonomic
Quantum Computation.Comment: Latex file, 24 pages. I added a new section (Quantum Computation), so
this paper became self-contained in a certain sens
Shell structures in oxygen isotopes described with modern nucleon-nucleon interactions
Shell structures in the N\simeq Z nucleus ^{17}O and the neutron-rich oxygen
isotopes ^{23}O and ^{25}O are microscopically described by calculating
single-particle energies with modern nucleon-nucleon interactions within the
framework of the unitary-model-operator approach. It is found that the effect
of three-body cluster terms on the single-particle energy is more important in
^{23}O and ^{25}O than ^{17}O.Comment: 5 pages, 1 figure, Talk at the International Symposium on "A New Era
of Nuclear Structure Physics (NENS03)", 19-22 Nov. 2003, Niigata, Japa
Three-Body-Cluster Effects on Lambda Single-Particle Energies in _{Lambda}^{17}O and_{Lambda}^{41}Ca
A method for a microscopic description of Lambda hypernuclei is formulated in
the framework of the unitary-model-operator approach. A unitarily transformed
hamiltonian is introduced and given in a cluster expansion form. The structure
of three-body-cluster terms are discussed especially on the Lambda
single-particle energy. The Lambda single-particle energies including the
three-body-cluster contributions are calculated for the 0s_{1/2}, 0p_{3/2} and
0p_{1/2} states in_{Lambda}^{17}O, and for the 0s_{1/2}, 0p_{3/2}, 0p_{1/2},
0d_{5/2}, 0d_{3/2} and 1s_{1/2} states in_{Lambda}^{41}Ca, using the Nijmegen
soft-core (NSC), NSC97a-f, the Juelich A (J A) and J B hyperon-nucleon
interactions. It is indicated that the three-body-cluster terms bring about
sizable effects in the magnitudes of the Lambda single-particle energies, but
hardly affect the Lambda spin-orbit splittings.Comment: LaTeX 19 pages including 7 figures, ptptex.sty is use
The unitary-model-operator approach to nuclear many-body problems
Microscopic nuclear structure calculations have been performed within the
framework of the unitary-model-operator approach. Ground-state and
single-particle energies are calculated for nuclei around ^{14}C, ^{16}O and
^{40}Ca with modern nucleon-nucleon interactions.Comment: 6 pages, 4 figures, Talk presented at the International Symposium on
Correlation Dynamics in Nuclei (CDN05), Jan. 1 - Feb. 4, 2005, Tokyo, Japa
Charge-dependent calculations of single-particle energies in nuclei around ^{16}O with modern nucleon-nucleon interactions
The binding energies of the ground states and several excited states related
to single-particle and -hole states in nuclei around ^{16}O are calculated
taking charge dependence into account. Effective interactions on the particle
basis are constructed from modern charge-dependent nucleon-nucleon interactions
and the Coulomb force within the framework of the unitary-model-operator
approach. Single-particle (-hole) energies are obtained from the energy
differences of the binding energies between a particle (hole) state in ^{17}O
or ^{17}F (^{15}N or ^{15}O) and the ground state of ^{16}O. The resultant
spin-orbit splittings are small for the hole state and large for the particle
state in comparison with the experimental values though the differences between
the experimental and calculated values are not very large. The charge
dependence of the calculated single-particle energies for the ground states are
in good agreement with the experimental values. Furthermore, the Thomas-Ehrman
shift due to the Coulomb force for the 1s_{1/2} states in ^{17}O and ^{17}F can
be observed.Comment: 14 pages, 12 figures, submitted to Phys. Rev.
Ground-state and single-particle energies of nuclei around ^{16}O, ^{40}Ca, and ^{56}Ni from realistic nucleon-nucleon forces
We perform ab initio calculations for nuclei around ^{16}O, ^{40}Ca, and
^{56}Ni using realistic nucleon-nucleon forces. In particular, ^{56}Ni is
computed as the heaviest nucleus in this kind of ab initio calculation.
Ground-state and single-particle energies including three-body-cluster effects
are obtained within the framework of the unitary-model-operator approach. It is
shown that the CD-Bonn nucleon-nucleon potential gives quite good results close
to the experimental values for all nuclei in the present work.Comment: 4 pages, 4 figures; accepted for publication in Physical Review
Letter
The unitary-model-operator approach to nuclear many-body problems
Microscopic nuclear structure calculations have been performed within the
framework of the unitary-model-operator approach. Ground-state and
single-particle energies are calculated for nuclei around ^{14}C, ^{16}O and
^{40}Ca with modern nucleon-nucleon interactions.Comment: 6 pages, 4 figures, Talk presented at the International Symposium on
Correlation Dynamics in Nuclei (CDN05), Jan. 1 - Feb. 4, 2005, Tokyo, Japa
The unitary-model-operator approach to nuclear many-body problems
Microscopic nuclear structure calculations have been performed within the
framework of the unitary-model-operator approach. Ground-state and
single-particle energies are calculated for nuclei around ^{14}C, ^{16}O and
^{40}Ca with modern nucleon-nucleon interactions.Comment: 6 pages, 4 figures, Talk presented at the International Symposium on
Correlation Dynamics in Nuclei (CDN05), Jan. 1 - Feb. 4, 2005, Tokyo, Japa
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