135,643 research outputs found

    Review of the "Bottom-Up" scenario

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    Thermalization of a longitudinally expanding color glass condensate with Bjorken boost invariant geometry is investigated within parton cascade BAMPS. Our main focus lies on the detailed comparison of thermalization, observed in BAMPS with that suggested in the Bottom-Up scenario. We demonstrate that the tremendous production of soft gluons via gg→ggggg \to ggg, which is shown in the Bottom-Up picture as the dominant process during the early preequilibration, will not occur in heavy ion collisions at RHIC and LHC energies, because the back reaction ggg→ggggg\to gg hinders the absolute particle multiplication. Moreover, contrary to the Bottom-Up scenario, soft and hard gluons thermalize at the same time. The time scale of thermal equilibration in BAMPS calculations is of order \as^{-2} (\ln \as)^{-2} Q_s^{-1}. After this time the gluon system exhibits nearly hydrodynamic behavior. The shear viscosity to entropy density ratio has a weak dependence on QsQ_s and lies close to the lower bound of the AdS/CFT conjecture.Comment: Quark Matter 2008 Proceeding

    A solution set for fine games

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    Bumb and Hoede have shown that a cooperative game can be split into two games, {\it the reward game} and {\it the fine game}, by considering the sign of quantities cSvc_S^v in the c-diagram of the game. One can then define a solution xx for the original game as x=xr−xfx=x_{r}-x_{f}, where xrx_{r} is a solution for the reward game and xfx_{f} is a solution for the fine game. Due to the distinction of cooperation rewards and fines, for allocating the fines one may use another solution concept than for the rewards

    A solution defined by fine vectors

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    Bumb and Hoede have shown that a cooperative game can be split into two games, the reward game and the fine game, by considering the sign of quantities cvSc_v^S in the c-diagram of the game. One can then define a solution xx for the original game as x=xr−xfx = x_r - x_f , where xrx_r is a solution for the reward game and xfx_f is a solution for the fine game. Due to the distinction of cooperation rewards and fines, for allocating the fines one may use another solution concept than for the rewards. In this paper, a fine vector is introduced and a solution is defined by fine vectors. The structure and properties of this solution are studied. And the solution is characterized as the unique solution having efficiency and f-potential property (resp. f-balanced contributions property)

    Higher-spin Realisations of the Bosonic String

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    It has been shown that certain WW algebras can be linearised by the inclusion of a spin--1 current. This provides a way of obtaining new realisations of the WW algebras. Recently such new realisations of W3W_3 were used in order to embed the bosonic string in the critical and non-critical W3W_3 strings. In this paper, we consider similar embeddings in W2,4W_{2,4} and W2,6W_{2,6} strings. The linearisation of W2,4W_{2,4} is already known, and can be achieved for all values of central charge. We use this to embed the bosonic string in critical and non-critical W2,4W_{2,4} strings. We then derive the linearisation of W2,6W_{2,6} using a spin--1 current, which turns out to be possible only at central charge c=390c=390. We use this to embed the bosonic string in a non-critical W2,6W_{2,6} string.Comment: 8 pages. CTP TAMU-10/95

    Energy levels of a parabolically confined quantum dot in the presence of spin-orbit interaction

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    We present a theoretical study of the energy levels in a parabolically confined quantum dot in the presence of the Rashba spin-orbit interaction (SOI). The features of some low-lying states in various strengths of the SOI are examined at finite magnetic fields. The presence of a magnetic field enhances the possibility of the spin polarization and the SOI leads to different energy dependence on magnetic fields applied. Furthermore, in high magnetic fields, the spectra of low-lying states show basic features of Fock-Darwin levels as well as Landau levels.Comment: 6 pages, 4 figures, accepted by J. Appl. Phy

    Liouville and Toda Solitons in M-theory

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    We study the general form of the equations for isotropic single-scalar, multi-scalar and dyonic pp-branes in superstring theory and M-theory, and show that they can be cast into the form of Liouville, Toda (or Toda-like) equations. The general solutions describe non-extremal isotropic pp-branes, reducing to the previously-known extremal solutions in limiting cases. In the non-extremal case, the dilatonic scalar fields are finite at the outer event horizon.Comment: Latex, 10 pages. Minor corrections to text and titl
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