vol. 85-1 | iTHES

Vol. 85-1, June 22nd, 2015


  • Upcoming Events
  • Event report
  • Person of the week

Person of the week




From the Office

The office of iTHES assistant, Ms.Chikako Oota is situated at the second floor of the main research building, room # 246. The extension number is 3261. She will be at the office from 10 a.m. to 16 p.m.

Upcoming Events

iTHES Colloquium
July 6 (Mon) 15:30-
"Thermodynamics of Information Processing"
Prof. Takahiro Sagawa (Dept. of Applied Phys., Univ. of Tokyo)
place: Nishina Hall (Building 13, E-4 area in the following map)
In this decade, thermodynamics of information has attracted renewed attentions in light of modern nonequilibrium statistical mechanics, leading to a new field of "information thermodynamics." This topic is related to the foundation of the second law of thermodynamics, which dates back to the thought experiment of "Maxwell's demon" in the nineteenth century. In this talk, I will review the recent progress in information thermodynamics, in both terms of theory and experiment. Theoretically, I will focus on the generalization of the second law of thermodynamics to information processing, where information contents and thermodynamic variables are treated on an equal footing. I will also talk about our experimental realization of Maxwell's demon with a single electron. Moreover, I will talk about our recent result on an application of information thermodynamics to biological signal transduction of E. Coli chemotaxis.

Event report

On June 15, 2015, Dr. Teruaki Enoto (experimental astrophysicist from Kyoto Univ.) gave a lecture on "Various properties of Neutron Stars and associated magnetic phenomena seen by X-ray observations" at the 12th QCD Club supported by ithes-phys team. More than 30 people participated in the lecture from various institutions in Tokyo area. After general introduction to the basic properties of neutron stars, he discussed the so-called "magnetars" which have strong magnetic field 10^{10-11} T. Such stars are the astrophysical laboratory for fundamental physics, i.e. dense matter, strong gravity, strong magnetic field, neutrino physics, etc. In the next generation X-ray satellites, information on the interior of the neutron stars could be extracted from the measurements of the cooling, mass and radius of neutron stars. Finally, he discussed the various future projects on neutron star observations. Hot discussions have been continued during and after the lecture for more than 2 hours.

Person of the week

Recently, the research on the 5d transition-metal oxides has drawn attentions in condensed matter physic because of their rich physical properties. The best studied members are iridates such as Sr2IrO4 and Na2IrO3. They show exotic physical properties and electronic excitation behaviors due to the mutual interplay of electronic degrees of freedom such as bandwidth, Coulomb correlation, and spin-orbit coupling. Recent experimental measurements of the optical conductivity (OC) and resonant inelastic x-ray scattering (RIXS) spectra have revealed their characteristic properties of the magnetic, spin-orbit (SO), and electron-hole (e-h) excitations.
In this paper, we have investigated the electronic excitations in Na2IrO3 by using the numerical method. We calculated theoretical OC and RIXS spectra (see Fig. 1 and 2) and compared them with experimental observations. We verified the existence of unusual Fano-type coupling between SO and e-h excitations which appear in similar energy region and the validity of strong relativistic electronic structure of local 5d orbital.

FIG. 1: Theoretical optical conductivity FIG. 2: Theoretical RIXS spectra
Beom Hyun Kim, G. Khaliullin, and B. I. Min,
“Electronic excitations in the edge-shared relativistic Mott insulator: Na2IrO3”