金属化合物を含む有機反応の研究

京都大学0048新制・課程博士工学博士甲第1716号工博第455号新制||工||335(附属図書館)4491UT51-61-I189京都大学大学院工学研究科合成化学専攻(主査)教授 古川 淳二, 教授 熊田 誠, 教授 三枝 武夫学位規則第5条第1項該当Kyoto UniversityDA

Reduced dynamics with Poincar\'e symmetry in an open quantum system

We consider how the reduced dynamics of an open quantum system coupled to an environment admits the Poincar\'e symmetry. The reduced dynamics is described by a dynamical map, which is given by tracing out the environment from the total unitary evolution without initial correlations. We investigate the dynamical map which is invariant under the Poincar\'e group. Based on the unitary representation theory of the Poincar\'e group, we develop a systematic way to give such a dynamical map. Using this way, we derive the dynamical map of a massive particle with a finite spin and a massless particle with a finite spin and a nonzero momentum. The dynamical map of a spinless massive particle is exemplified and the conservation of the Poincar\'e generators is discussed. We then find the map with the Poincar\'e invariance and the four-momentum conservation. Further, we show that the conservation of the angular momentum and the boost operator makes the map of a spinless massive particle unitaryComment: 36 pages, 1 tabl

Orbital dependent magnetic exchange interaction in CeXc_{\text{c}} (Xc_{\text{c}}=S, Se, Te)

Dispersion relations of the crystal-field excitations in cubic antiferromagnets CeTe, CeSe, and CeS have been investigated by inelastic neutron scattering using single crystalline samples. The Fourier transform of the magnetic exchange interaction $J(q)$ obtained from the crystal-field dispersion is largely different from that of the mean-field interaction obtained from the N\'eel temperature and the Weiss temperature. From detailed reexamination of the magnetic susceptibility and these $J(q)$ relations, we conclude that the magnetic exchange interaction is dependent on the crystal-field levels. The interaction associated with the $\Gamma_8$ excited state is stronger than that with the $\Gamma_7$ ground state.Comment: 6 pages, 3 figures, proceedings of SCES201

Squeezing of primordial gravitational waves as quantum discord

We investigate the squeezing of primordial gravitational waves (PGWs) in terms of quantum discord. We construct a classical state of PGWs without quantum discord and compare it with the Bunch-Davies vacuum. Then it is shown that the oscillatory behavior of the angular-power spectrum of the cosmic microwave background (CMB) fluctuations induced by PGWs can be the signature of the quantum discord of PGWs. In addition, we discuss the effect of quantum decoherence on the entanglement and the quantum discord of PGWs for super-horizon modes. For the state of PGWs with decoherence effect, we examine the decoherence condition and the correlation condition introduced by C. Kiefer et al. (Class. Quantum Grav. 24 (2007) 1699). We show that the decoherence condition is not sufficient for the separability of PGWs and the correlation condition implies that the PGWs in the matter-dominated era have quantum discord.Comment: 33 pages, 10 figure

Negativity volume of the generalized Wigner function in gravitating hybrid system

We evaluate the gravity-induced negativity volume of the generalized Wigner function in a hybrid system consisting of a particle in a two-localized superposition state and an oscillator. The generalized Wigner function can capture the nonclassicality of the system. The increase in the negativity volume of the generalized Wigner function can be an indicator of the entanglement generation, which is demonstrated in the hybrid system generating the gravity-induced entanglement in various initial states. Moreover, by comparing the behaviors of the negativity volume with the entanglement fidelity, we show that the nonclassical feature of entanglement is properly identified by the criterion based on the negativity volume of the generalized Wigner function when the oscillator is initially in a thermal state.Comment: 12 pages, 5 figure