Spin is a fundamental property of electrons and plays an important role in quantum information processing and storage. Photon polarization which is essential for the quantum information communication also possesses the similar property called a pseudo-spin. Quantum information embedded in photon and electron can be exchanged via the common spin degree of freedom. The quantum information exchange or quantum media conversion between two different quantum media is essential for the quantum information technology based on the fact that a quantum is not only a minimum element of energy but also a minimum element of information. We introduce spin state transfer that demonstrates the transfer of light-polarization superposition state into the electron spin state and spin state tomography that demonstrates reconstruction of electron spin state by the reverse transfer of electron-spin superposition state into light polarization state in a view point of quantum information exchange between a photon and an electron.
Dynamic light scattering is an important technique to investigate material dynamics through the observation of the thermal fluctuations. In this article, we introduce experimental details of the optical beating Brillouin spectroscopy. New techniques of the phonon resonance measurement and real-time observation of phonon propagation are also described, as well as their application to gas and solid materials.
Recently, a new duality called the Kerr/CFT correspondence between four-dimensional non-supersymmetric but extremal Kerr black holes and a two-dimensional CFT was proposed, and the Bekenstein-Hawking entropy of the black holes was reproduced as the statistical entropy of the dual CFT using the Cardy formula. In this manuscript, we review the Kerr/CFT correspondence and explain our work on the generalization of this correspondence to fairly general black holes.
We review recent studies on the orbital diamagnetism of graphenes. Graphene exhibits a huge diamagnetic susceptibility due to the orbital motion of electrons, which is quite different from the conventional Landau diamagnetism. We study the electric response of graphene to arbitrary magnetic objects outside, to show that the interacting force can be macroscopic even though the system consists of just one atomic layer.
We report on experiments to search for axions, light neutral pseudoscalar particles yet to be discovered. Its existence is implied to solve the so-called strong CP problem. The axion could be produced in the solar core through the Primakoff effect. It can be converted back to an x-ray in a strong magnetic field in the laboratory by the inverse process. We search for such x-rays coming from the direction of the sun with the TOKYO AXION HELIOSCOPE.
Enantiomers in many proteins, sugars and pharmaceuticals crystallize into two forms that are mirror images of each other like our right and left hands. X-rays, which are normally useful in determining the structure of materials and biomolecules, are much less sensitive to the 'handedness' of an enantiomer. We have shown that right and left circularly polarised (RCP and LCP) X-rays at the resonant energy can distinguish 'left' from 'right' low quartz, whose crystal structures are mirror images of each other.