462 research outputs found

    SANTRAUKOS

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    Masthead

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    One-step generation of high-quality squeezed and EPR states in cavity QED

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    We show how to generate bilinear (quadratic) Hamiltonians in cavity quantum electrodynamics (QED) through the interaction of a single driven three-level atom with two (one) cavity modes. With this scheme it is possible to generate one-mode mesoscopic squeezed superpositions, two-mode entanglements, and two-mode squeezed vacuum states (such the original EPR state), without the need for Ramsey zones and external parametric amplification. The degree of squeezing achieved is up to 99% with currently feasible experimental parameters and the errors due to dissipative mechanisms become practically negligible

    Coulomb parameters and photoemission for the molecular metal TTF-TCNQ

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    We employ density-functional theory to calculate realistic parameters for an extended Hubbard model of the molecular metal TTF-TCNQ. Considering both intra- and intermolecular screening in the crystal, we find significant longer-range Coulomb interactions along the molecular stacks, as well as inter-stack coupling. We show that the long-range Coulomb term of the extended Hubbard model leads to a broadening of the spectral density, likely resolving the problems with the interpretation of photoemission experiments using a simple Hubbard model only.Comment: 4 pages, 2 figure

    New gauge bosons from the littlest Higgs model and the process e+ettˉe^{+}e^{-}\to t\bar{t}

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    In the context of the littlest Higgs(LH)(LH) model, we study the process e+ettˉ e^{+}e^{-}\to t\bar{t}. We find that the new gauge bosons ZHZ_{H} and BHB_{H} can produce significant correction effects on this process, which can be further enhanced by the suitably polarized beams. In most of the parameter space preferred by the electroweak precision data, the absolute value of the relative correction parameter RBHR_{B_{H}} is larger than 5%. As long as 1TeVMZH1.5TeV1TeV\leq M_{Z_{H}}\leq 1.5TeV and 0.3c0.5,0.3\leq c\leq 0.5, the absolute value of the relative correction parameter RZHR_{Z_{H}} is larger than 5%. With reasonable values of the parameters of the LHLH model, the possible signals of the new gauge bosons BHB_{H} and ZHZ_{H} can be detected via the process e+ettˉ e^{+}e^{-} \to t\bar{t} in the future LCLC experiments with the c.m. energy S=800GeV\sqrt{S}=800GeV. BHB_{H} exchange and ZHZ_{H} exchange can generate significantly corrections to the forward-backward asymmetry AFB(ttˉ)A_{FB}(t\bar{t}) only in small part of the parameter space.Comment: 18 pages, 6 figure

    The Lorentz and CPT violating effects on the Z\to l^+ l^- decay

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    We study the Lorentz and CPT violating effects on the branching ratio BR, the CPT violating asymmetry A_{CPT} and the ratio of the decay width, including only the Lorentz violating effects, to the one obtained in the standard model, for the flavor dependent part of the lepton flavor conserving Z\to l^+ l^- (l=e,\mu,\tau) decay. The inclusion of the Lorentz and CPT violating effects to the standard model contribution is too small to be detected, since the corresponding coefficients are highly suppressed at the low energy scale.Comment: 11 pages, 6 figure

    SANTRAUKOS

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