2,758 research outputs found

    Electroweak phase transition in technicolor

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    Several phenomenologically viable walking technicolor models have been proposed recently. I demonstrate that these models can have first order electroweak phase transitions, which are sufficiently strong for electroweak baryogenesis. Strong dynamics can also lead to several separate transitions at the electroweak scale, with the possibility of a temporary restoration and an extra breaking of the electroweak symmetry. First order phase transitions will produce gravitational waves, which may be detectable at future experiments.Comment: 6 pages, 4 figures. Talk at PASCOS 2010 conference, Valencia, 19-23 July 201

    Information completeness in Nelson algebras of rough sets induced by quasiorders

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    In this paper, we give an algebraic completeness theorem for constructive logic with strong negation in terms of finite rough set-based Nelson algebras determined by quasiorders. We show how for a quasiorder RR, its rough set-based Nelson algebra can be obtained by applying the well-known construction by Sendlewski. We prove that if the set of all RR-closed elements, which may be viewed as the set of completely defined objects, is cofinal, then the rough set-based Nelson algebra determined by a quasiorder forms an effective lattice, that is, an algebraic model of the logic E0E_0, which is characterised by a modal operator grasping the notion of "to be classically valid". We present a necessary and sufficient condition under which a Nelson algebra is isomorphic to a rough set-based effective lattice determined by a quasiorder.Comment: 15 page

    Representation of Nelson Algebras by Rough Sets Determined by Quasiorders

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    In this paper, we show that every quasiorder RR induces a Nelson algebra RS\mathbb{RS} such that the underlying rough set lattice RSRS is algebraic. We note that RS\mathbb{RS} is a three-valued {\L}ukasiewicz algebra if and only if RR is an equivalence. Our main result says that if A\mathbb{A} is a Nelson algebra defined on an algebraic lattice, then there exists a set UU and a quasiorder RR on UU such that ARS\mathbb{A} \cong \mathbb{RS}.Comment: 16 page

    Hydrogen Atom in Relativistic Motion

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    The Lorentz contraction of bound states in field theory is often appealed to in qualitative descriptions of high energy particle collisions. Surprisingly, the contraction has not been demonstrated explicitly even in simple cases such as the hydrogen atom. It requires a calculation of wave functions evaluated at equal (ordinary) time for bound states in motion. Such wave functions are not obtained by kinematic boosts from the rest frame. Starting from the exact Bethe-Salpeter equation we derive the equal-time wave function of a fermion-antifermion bound state in QED, i.e., positronium or the hydrogen atom, in any frame to leading order in alpha. We show explicitly that the bound state energy transforms as the fourth component of a vector and that the wave function of the fermion-antifermion Fock state contracts as expected. Transverse photon exchange contributes at leading order to the binding energy of the bound state in motion. We study the general features of the corresponding fermion-antifermion-photon Fock states, and show that they do not transform by simply contracting. We verify that the wave function reduces to the light-front one in the infinite momentum frame.Comment: 20 pages, 10 figures; v2: some changes in discussion, accepted for publication in Phys.Rev.

    Sulfobutyl Ether b-Cyclodextrin (SBE-b-CD) in Eyedrops Improves the Tolerability of a Topically Applied Pilocarpine Prodrug in Rabbits

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    This is the publisher's version, also available electronically from http://dx.doi.org/10.1089/jop.1995.11.95The effects of a novel, modified β-cyclodextrin (SBE4-β-CD; a variably substituted sulfobutyl ether with an average degree of substitution of four) on eye irritation and miotic response of an ophthalmically applied pilocarpine prodrug, O,O'-dipropionyl-(1,4-xylylene) bispilocarpate, in albino rabbits were studied. Compared to the commercial pilocarpine eyedrop solution (163 mM, equivalent to 3.4% pilocarpine), 12 - 24 mM pilocarpine prodrug solutions (equivalent to 0.5 - 1.0% pilocarpine, respectively) decreased peak miotic intensity (Imax) and increased the time to reach peak (tmax), but did not significantly affect values for the area under the miosis versus time curves (AUC), i.e. 12 - 24 mM pilocarpine prodrug appeared to be equivalent to 163 mM pilocarpine. Ocularly applied 12 - 24 mM pilocarpine prodrug solutions, however, were more irritating than a commercial pilocarpine eyedrop solution. Coadministered SBE4-β-CD significantly decreased the eye irritation of the pilocarpine prodrug solutions. Coadministered SBE4-β-CD did not affect the miotic response of prodrug solution when the molar ratio of SBE4-β-CD to prodrug was low. However, increasing the molar ratio of SBE4-β-CD to prodrug decreased the Imax and AUC values. The results show that eye irritation of the pilocarpine prodrug is prevented by levels of SBE4-β-CD that do not affect the apparent ocular absorption of the prodrug

    Cold Collision Frequency Shift in Two-Dimensional Atomic Hydrogen

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    We report a measurement of the cold collision frequency shift in atomic hydrogen gas adsorbed on the surface of superfluid 4He at T<=90 mK. Using two-photon electron and nuclear magnetic resonance in 4.6 T field we separate the resonance line shifts due to the dipolar and exchange interactions, both proportional to surface density sigma. We find the clock shift Delta v_c = -1.0(1)x10^-7 Hz cm^-2 x sigma, which is about 100 times smaller than the value predicted by the mean field theory and known scattering lengths in the 3D case.Comment: 4 pages, 3 figure
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