5,483 research outputs found
Algebraic structure of the Feynman propagator and a new correspondence for canonical transformations
We investigate the algebraic structure of the Feynman propagator with a
general time-dependent quadratic Hamiltonian system. Using the Lie-algebraic
technique we obtain a normal-ordered form of the time-evolution operator, and
then the propagator is easily derived by a simple ``Integration Within Ordered
Product" (IWOP) technique.It is found that this propagator contains a classical
generating function which demonstrates a new correspondence between classical
and quantum mechanics
Three-nucleon interactions: A frontier in nuclear structure
Three-nucleon interactions are a frontier in understanding and predicting the
structure of strongly-interacting matter in laboratory nuclei and in the
cosmos. We present results and discuss the status of first calculations with
microscopic three-nucleon interactions beyond light nuclei. This coherent
effort is possible due to advances based on effective field theory and
renormalization group methods in nuclear physics.Comment: 7 pages, 11 figures, talk at International Symposium on New Facet of
Three-Nucleon Force (FM50), Tokyo, October, 200
Microstructural influences on stress migration in electroplated Cu metallization
科研費報告書収録論文(課題番号:13450281・基盤研究(B)(2) ・H13~H15/研究代表者:小池, 淳一/超高速LSI用Cu配線におけるボイド形成機構の研究
Affleck-Dine leptogenesis via multiscalar evolution in a supersymmetric seesaw model
A leptogenesis scenario in a supersymmetric standard model extended with
introducing right-handed neutrinos is reconsidered. Lepton asymmetry is
produced in the condensate of a right-handed sneutrino via the Affleck-Dine
mechanism. The LH_u direction develops large value due to a negative effective
mass induced by the right-handed sneutrino condensate through the Yukawa
coupling of the right-handed neutrino, even if the minimum during the inflation
is fixed at the origin. The lepton asymmetry is nonperturbatively transfered to
the LH_u direction by this Yukawa coupling.Comment: 19 pages, 3 figures. Revised version for publication. The model was
modified to fix some problem
Spin dependent recombination based magnetic resonance spectroscopy of bismuth donor spins in silicon at low magnetic fields
Low-field (6-110 mT) magnetic resonance of bismuth (Bi) donors in silicon has
been observed by monitoring the change in photoconductivity induced by spin
dependent recombination. The spectra at various resonance frequencies show
signal intensity distributions drastically different from that observed in
conventional electron paramagnetic resonance, attributed to different
recombination rates for the forty possible combinations of spin states of a
pair of a Bi donor and a paramagnetic recombination center. An excellent
tunability of Bi excitation energy for the future coupling with superconducting
flux qubits at low fields has been demonstrated.Comment: 5 pages, 4 figure
Secondary Heavy Chain Rearrangement: A Mechanism for Generating Anti–double-stranded DNA B Cells
The chronic graft-versus-host (cGVH) reaction results in a syndrome that closely resembles systemic lupus erythematosus (SLE). It is induced in nonautoimmune mice by the transfer of alloreactive T cells. The availability of anti-DNA transgenes allows us to study the genetic origins of autoantibodies in this model. We induced cGVH in two anti-DNA H chain site-directed transgenic mouse strains. This resulted in clonal expansion and selection of specific mutations in the anti–double-stranded (ds) DNA B cell population. These data, together with a high frequency of anti-dsDNA B cell clones recovered as hybridomas, suggested that anti-dsDNAs are the product of an antigen-driven immune response. Genetic analysis associated this response with the generation of anti-dsDNA B cells through secondary rearrangements that replaced the site-directed transgene (sd-tg) with endogenous VH genes
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