77,473 research outputs found

    Comment on "Spectroscopic Evidence for Multiple Order Parameter Components in the Heavy Fermion Superconductor CeCoIn5_5"

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    Recently, Rourke et al. reported point-contact spectroscopy results on the heavy-fermion superconductor CeCoIn5_5 [1]. They obtained conductance spectra on the c-axis surfaces of CeCoIn5_5 single crystals. Their major claims are two-fold: CeCoIn5_5 has i) d-wave pairing symmetry and ii) two coexisting order parameter components. In this Comment, we show that these claims are not warranted by the data presented. [1] Rourke et al., Phys. Rev. Lett. 94, 107005 (2005).Comment: accepted for publication in Phys. Rev. Lett., final for

    Genus Topology of the Cosmic Microwave Background from the WMAP 3-Year Data

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    We have independently measured the genus topology of the temperature fluctuations in the cosmic microwave background seen in the Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data. A genus analysis of the WMAP data indicates consistency with Gaussian random-phase initial conditions, as predicted by standard inflation. We set 95% confidence limits on non-linearities of -101 < f_{nl} < 107. We also find that the observed low l (l <= 8) modes show a slight anti-correlation with the Galactic foreground, but not exceeding 95% confidence, and that the topology defined by these modes is consistent with that of a Gaussian random-phase distribution (within 95% confidence).Comment: MNRAS LaTeX style (mn2e.cls), EPS and JPEG figure

    Black Hole Solutions of Kaluza-Klein Supergravity Theories and String Theory

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    We find U(1)_{E} \times U(1)_{M} non-extremal black hole solutions of 6-dimensional Kaluza-Klein supergravity theories. Extremal solutions were found by Cveti\v{c} and Youm\cite{C-Y}. Multi black hole solutions are also presented. After electro-magnetic duality transformation is performed, these multi black hole solutions are mapped into the the exact solutions found by Horowitz and Tseytlin\cite{H-T} in 5-dimensional string theory compactified into 4-dimensions. The massless fields of this theory can be embedded into the heterotic string theory compactified on a 6-torus. Rotating black hole solutions can be read off those of the heterotic string theory found by Sen\cite{Sen3}.Comment: 23 pages text(latex), a figure upon reques

    Observation of b2_2 symmetry vibrational levels of the SO2_2 \tilde{\mbox{C}} 1^1B2_2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

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    The C~\mathrm{\tilde{C}} 1^1B2_2 state of SO2_2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2_2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X~\mathrm{\tilde{X}} state are vibronically forbidden. We use IR-UV double resonance to observe the b2_2 vibrational levels of the C~\mathrm{\tilde{C}} state below 1600 cm1^{-1} of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong cc-axis Coriolis interactions between levels of a1_1 and b2_2 vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C~\mathrm{\tilde{C}} electronic state

    Monte Carlo simulations of bosonic reaction-diffusion systems

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    An efficient Monte Carlo simulation method for bosonic reaction-diffusion systems which are mainly used in the renormalization group (RG) study is proposed. Using this method, one dimensional bosonic single species annihilation model is studied and, in turn, the results are compared with RG calculations. The numerical data are consistent with RG predictions. As a second application, a bosonic variant of the pair contact process with diffusion (PCPD) is simulated and shown to share the critical behavior with the PCPD. The invariance under the Galilean transformation of this boson model is also checked and discussion about the invariance in conjunction with other models are in order.Comment: Publishe

    Point-contact spectroscopy in heavy-fermion superconductors

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    We develop a minimal model to calculate point-contact spectra between a metallic tip and a superconducting heavy-fermion system. We apply our tunneling model to the heavy fermion CeCoIn5, both in the normal and superconducting state. In point-contact and scanning tunneling spectroscopy many heavy-fermion materials, like CeCoIn5, exhibit an asymmetric differential conductance, dI/dV, combined with a strongly suppressed Andreev reflection signal in the superconducting state. We argue that both features may be explained in terms of a multichannel tunneling model in the presence of localized states near the interface. We find that it is not sufficient to tunnel into two itinerant bands of light and heavy electrons to explain the Fano line shape of the differential conductance. Localized states in the bulk or near the interface are an essential component for quantum interference to occur when an electron tunnels from the metallic tip of the point contact into the heavy-fermion system.Comment: 13 pages, 9 figures. Accepted for publication in Physical Review

    Separable states to distribute entanglement

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    It was shown that two distant particles can be entangled by sending a third particle never entangled with the other two [T. S. Cubitt et al., Phys. Rev. Lett. 91, 037902 (2003)]. In this paper, we investigate a class of three-qubit separable states to distribute entanglement by the same way, and calculate the maximal amount of entanglement which two particles of separable states in the class can have after applying the way.Comment: 4 pages, no figures, Revised argumen

    Rotating Black Holes at Future Colliders. III. Determination of Black Hole Evolution

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    TeV scale gravity scenario predicts that the black hole production dominates over all other interactions above the scale and that the Large Hadron Collider will be a black hole factory. Such higher dimensional black holes mainly decay into the standard model fields via the Hawking radiation whose spectrum can be computed from the greybody factor. Here we complete the series of our work by showing the greybody factors and the resultant spectra for the brane localized spinor and vector field emissions for arbitrary frequencies. Combining these results with the previous works, we determine the complete radiation spectra and the subsequent time evolution of the black hole. We find that, for a typical event, well more than half a black hole mass is emitted when the hole is still highly rotating, confirming our previous claim that it is important to take into account the angular momentum of black holes.Comment: typoes in eqs(82)-(84) corrected; version to appear in Phys. Rev. D; references and a footnote added; same manuscript with high resolution embedded figures available on http://www.gakushuin.ac.jp/univ/sci/phys/ida/paper
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