17,558 research outputs found

    Current-induced persistent magnetization in a relaxorlike manganite

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    A single crystal of 7% Fe-doped (La0.7_{0.7}Pr0.3_{0.3})0.65_{0.65}Ca0.35_{0.35}MnO3_3 shows up as a typical relaxor ferromagnet, where ferromagnetic metallic and charge-orbital-ordered insulating clusters coexist with controllable volume fraction by external stimuli. There, the persistent ferromagnetic metallic state can be produced by an electric-current excitation as the filamentary region, the magnetization in which is increased by ~0.4μB\mu_{\rm B} per Mn. A clear distinction from the current heating effect in a magnetic field, which conversely leads to a decrease in ferromagnetic fraction, enables us to bi-directionally switch both the magnetization and resistance by applying the voltages with different magnitudes.Comment: 4 pages, 3 figure

    Correlation Functions in Two-Dimensional Dilaton Gravity

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    The Liouville approach is applied to the quantum treatment of the dilaton gravity in two dimensions. The physical states are obtained from the BRST cohomology and correlation functions are computed up to three-point functions. For the N=0N=0 case (i.e., without matter), the cosmological term operator is found to have the discrete momentum that plays a special role in the c=1c=1 Liouville gravity. The correlation functions for arbitrary numbers of operators are found in the N=0N=0 case, and are nonvanishing only for specific ``chirality'' configurations.Comment: 14 pages, TIT/HEP-204, STUPP-92-13

    Supergravity in 2+ϵ2+\epsilon Dimensions

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    Supergravity theory in 2+ϵ2+\epsilon dimensions is studied. It is invariant under supertransformations in 2 and 3 dimensions. One-loop divergence is explicitly computed in the background field method and a nontrivial fixed point is found. In quantizing the supergravity, a gauge fixing condition is devised which explicitly isolates conformal and superconformal modes. The renormalization of the gravitationally dressed operators is studied and their anomalous dimensions are computed. Problems to use the dimensional reduction are also examined.Comment: 36 pages, TIT/HEP-238, Imperial/TP/93-94/

    Domain walls with non-Abelian orientational moduli

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    Domain walls with non-Abelian orientational moduli are constructed in U(N) gauge theories coupled to Higgs scalar fields with degenerate masses. The associated global symmetry is broken by the domain walls, resulting in the Nambu-Goldstone (and quasi-Nambu-Goldstone) bosons, which form the non-Abelian orientational moduli. As walls separate, the wave functions of the non-Abelian orientational moduli spread between domain walls. By taking the limit of Higgs mass differences to vanish, we clarify the convertion of wall position moduli into the non-Abelian orientational moduli. The moduli space metric and its Kahler potential of the effective field theory on the domain walls are constructed. We consider two models: a U(1) gauge theory with several charged Higgs fields, and a U(N) gauge theory with 2N Higgs fields in the fundamental representation. More details are found in our paper published in Phys. Rev. D77 (2008) 125008 [arXiv:0802.3135 [hep-th]].Comment: contribution to the Proceedings of he 1st MCCQG conference at Crete, sept. 2009, to appear in Journal of Physics: Conference Series of IO

    Results of time evolution analyses of B-decays at Belle

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    We report results of proper-time evolution analyses of B decays at Belle, based on a 29.1/fb data sample recorded at the Upsilon (4S) resonance. These results include measurements of sin2phi_1, the lifetime of B-mesons, and the mass-difference between two mass eigenstates of the B^0-B^0-bar system (Delta-m_d). Delta-m_d is measured using three different methods: fully reconstructed hadronic modes, a fully reconstructed semi-leptonic mode, and a partially reconstructed D*+ pi- mode.Comment: 13 pages, contributed to the proceedings of the Fifth KEK Topical Conference, 20-22, Nov. 2001, Tsukuba, Japa