arXiv subjects

Akio Sugamoto

Publications and source records attributed to Akio Sugamoto.

75 records · Page 5Linked to original sources

arXiv1994

Electroweak Baryogenesis and the Phase Transition Dynamics

The baryogenesis is reanalyzed based on the model by A.G.Cohen et al., in which the lepton number, generated by the neutrinos' scattering from the bubble walls appearing in the development of the electroweak phase transition, is converted to the baryon number excess through the sphaleron transition. A formula obtained in this paper on the lepton number production rate is correct for the both thin and thick walls within the linear approximation. Investigation on the time-development of the first order phase transition is simulated, including the temporal change of the wall velocity as well as the fusion effect of the bubbles. The details of such phase transition dynamics are found to affect considerably the final value of the baryon number excess.

hep-ph↗

arXiv1994

Swimming of Microorganism and the String- and Membrane- like Algebra

Swimming of microorganisms is further developed from a viewpoint of strings and membranes swimming in the incompressible fluid of low Reynolds number. In our previous paper the flagellated motion was analyzed in two dimensional fluid, by using the method developed in the ciliated motion with the Joukowski transformation. This method is further refined by incorporating the inertia term of fluid as the perturbation. Understanding of the algebra controlling the deformation of microorganisms in the fluid is further developed, obtaining the central extension of the algebra with the help of the recent progress on the $W_{1+\infty}$ algebra. Our previous suggestion on the usefulness of the $N$-point string- and membrane-like amplitudes for studying the collective swimming motion of $N-1$ microorganisms is also examined.

hep-th↗

arXiv1994

Swimming of Microorganisms Viewed from String and Membrane Theories

Swimming of microorganisms is studied from a viewpoint of extended objects (strings and membranes) swimming in the incompressible f luid of low Reynolds number. The flagellated motion is analyzed in two dimensional fluid, by using the method developed in the ciliated motion with the Joukowski transformation. Discussion is given on the conserved charges and the algebra which are associated with the area (volume)- preserving diffeomorphisms giving the swimming motion of microorganisms. It is also suggested that the $N$-point string- and membrane-like amplitudes are useful for studying the collective swimming motion of microorganisms when fluctuation of the vorticity distribution exists in the sticky or rubber-like fluid.

hep-th↗