32,560 research outputs found

    All Optical Measurement Proposed for the Photovoltaic Hall Effect

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    We propose an all optical way to measure the recently proposed "photovoltaic Hall effect", i.e., a DC Hall effect induced by a circularly polarized light in the absence of static magnetic fields. For this, we have calculated the Faraday rotation angle induced by the photovoltaic Hall effect with the Kubo formula extended for photovoltaic optical response in the presence of strong AC electric fields treated with the Floquet formalism. We also point out the possibility of observing the effect in three-dimensional graphite, and more generally in multi-band systems such as materials described by the dp-model.Comment: 5 page

    Discovery of the Pigtail Molecular Cloud in the Galactic Center

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    This paper reports the discovery of a helical molecular cloud in the central molecular zone (CMZ) of our Galaxy. This "pigtail" molecular cloud appears at (l, b, V_LSR) ~ (-0.7deg, +0.0deg, -70 to -30 km/s), with a spatial size of ~ (20 pc)^2 and a mass of (2-6) 10^5 solar masses. This is the third helical gaseous nebula found in the Galactic center region to date. Line intensity ratios indicate that the pigtail molecular cloud has slightly higher temperature and/or density than the other normal clouds in the CMZ. We also found a high-velocity wing emission near the footpoint of this cloud. We propose a formation model of the pigtail molecular cloud. It might be associated with a magnetic tube that is twisted and coiled because of the interaction between clouds in the innermost x_1 orbit and ones in the outermost x_2 orbit.Comment: 15 pages, 6 figures, accepted for publication in Astrophysical Journa

    H dibaryon in the QCD sum rule

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    The QCD sum rule is applied to the H dibaryon and is compared to the flavor non-singlet di-nucleon. We find that the H dibaryon is almost degenerate to the di-nucleon in the SU(3)flavorSU(3)_{flavor} limit and therefore is not deeply bound as far as th\ e threshold parameter is adjusted not to have a di-nucleon bound state. After introducing the SU(3)fSU(3)_{f} breaking effects, the H dibaryon is found to be bound by 40MeV40 MeV below the ΛΛ\Lambda \Lambda threshold.Comment: 10 pages 4 uuencoded figures containe

    Pauli-blocking Effect in a Quark Model

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    Pauli-Blocking effect on the kinetic term is investigated by employing the quark cluster model. The effect can be understood by the change of the degrees of the mixing between the incoming wave and the 0â„“\ell state of the inter-cluster wave function, which can be expressed by a potential which is highly nonlocal. We look into the properties of this effect by comparing equivalent local potentials. In the channel where the Pauli-blocking effect is small, the on-shell equivalent local potential simulates the nonlocal potential well even for the off-shell behavior. On the other hand, the off-shell behavior is very different from the original one where the effect is large. This off-shell behavior, however, can well be simulated by considering the nonlocal matrix elements only between the 0s0s state and the other states. The energy dependent potentials are also constructed and found to be helpful to understand the energy dependence of the effect.Comment: 14 pages, 12 figure

    Two New and Remarkable Sightlines through the Galactic Center's Molecular Gas

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    Until now the known sources in the Galactic center with sufficiently smooth spectra and of sufficient brightness to be suitable for high resolution infrared absorption spectroscopy of interstellar gas occupied a narrow range of longitudes, from the central cluster of hot stars to approximately 30 pc east of the center. In order to more fully characterize the gas within the r ~ 180 pc central molecular zone it is necessary to find additional such sources that cover a much wider longitudinal range. We are in the process of identifying luminous dust-embedded objects suitable for spectroscopy within 1.2 deg in longitude and 0.1 deg in latitude of Sgr A* using the Spitzer GLIMPSE and the 2MASS catalogues. Here we present spectra of H3+ and CO towards two such objects, one located 140 pc west of Sgr A*, and the other located on a line of sight to the Sgr B molecular cloud complex 85 pc to the east of Sgr A*. The sightline to the west passes through two dense clouds of unusually high negative velocities and also appears to sample a portion of the expanding molecular ring. The spectra toward Sgr B reveal at least ten absorption components covering over 200 km/s and by far the largest equivalent width ever observed in an interstellar H3+line; they appear to provide the first near-infrared view into that hotbed of star formation.Comment: 13 pages, incl. 4 figures - accepted by ApJ Letters Dec 14, 2009; minor typos correcte

    Contact structure on mixed links

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    A strongly non-degenerate mixed function has a Milnor open book structures on a sufficiently small sphere. We introduce the notion of {\em a holomorphic-like} mixed function and we will show that a link defined by such a mixed function has a canonical contact structure. Then we will show that this contact structure for a certain holomorphic-like mixed function is carried by the Milnor open book
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