38,767 research outputs found

    Phase transitions in Ising model on a Euclidean network

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    A one dimensional network on which there are long range bonds at lattice distances l>1l>1 with the probability P(l)lδP(l) \propto l^{-\delta} has been taken under consideration. We investigate the critical behavior of the Ising model on such a network where spins interact with these extra neighbours apart from their nearest neighbours for 0δ<20 \leq \delta < 2. It is observed that there is a finite temperature phase transition in the entire range. For 0δ<10 \leq \delta < 1, finite size scaling behaviour of various quantities are consistent with mean field exponents while for 1δ21\leq \delta\leq 2, the exponents depend on δ\delta. The results are discussed in the context of earlier observations on the topology of the underlying network.Comment: 7 pages, revtex4, 7 figures; to appear in Physical Review E, minor changes mad

    Remark about Non-BPS D-Brane in Type IIA Theory

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    In this paper we would like to show simple mechanisms how from the action for non-BPS D-brane we can obtain action describing BPS D(p-1)-brane in Type IIA theory.Comment: 13 pages, completely rewritten pape

    The Double Dividend Hypothesis and Trade Liberalization

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    This paper studies how simultaneously liberalizing trade and tightening environmental policy affect welfare in a second-best world. We consider a three-good two-factor small open economy. We allow for non-tradables and for market power in the export market. The government is constrained to balance its budget at all times through distortionary taxes: a given income transfer has to be financed out of tariff and pollution tax revenue. We show that the switch from trade tariffs to environmental taxes can yield an increase in real income thus providing a second dividend in addition to the environmental improvement.environmental policy;trade liberalization;double dividend;non-tradables

    Glassy Aging with Modified Kohlrausch-Williams-Watts Form

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    In this report we address the question whether aging in the non equilibrium glassy state is controlled by the equilibrium alpha-relaxation process which occur at temperatures above Tg. Recently Lunkenheimer et. al. [Phys. Rev. Lett. 95, 055702 (2005)] proposed a model for the glassy aging data of dielectric relaxation using a modified Kohlrausch-Williams-Watts (KWW) form. The aging time dependence of the relaxation time is defined by these authors through a functional relation involving the corresponding frequency but the stretching exponent is same as the alpha-relaxation stretching exponent. We present here an alternative functional form directly involving the relaxation time itself. The proposed model fits the data of Lunkenheimer et. al. perfectly with a stretching exponent different from the alpha-relaxation stretching exponent.Comment: 1 TeX file, 10 eps figure

    A classification of incomparable states

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    Let (\{| \psi> ,| \phi>}) be an incomparable pair of states ((| \psi \nleftrightarrow | \phi>)), \emph, i.e., (| \psi>) and (| \phi>) cannot be transformed to each other with probability one by local transformations and classical communication (LOCC). We show that incomparable states can be multiple-copy transformable, \emph, i.e., there can exist a \emph{k}, such that (| \psi> ^{\otimes k+1}\to | \phi> ^{\otimes k+1}), i.e., (k+1) copies of (| \psi>) can be transformed to (k+1) copies of (| \phi>) with probability one by LOCC but (| \psi> ^{\otimes n}\nleftrightarrow | \phi> ^{\otimes n} \forall n\leq k). We call such states \emph{k}-copy LOCC incomparable. We provide a necessary condition for a given pair of states to be \emph{k}-copy LOCC incomparable for some \emph{k}. We also show that there exist states that are neither \emph{k}-copy LOCC incomparable for any \emph{k} nor catalyzable even with multiple copies. We call such states strongly incomparable. We give a sufficient condition for strong incomparability. We demonstrate that the optimal probability of a conclusive transformation involving many copies, (p_{max}(| \psi> ^{\otimes m}\to | \phi> ^{\otimes m})) can decrease exponentially with the number of source states (m), even if the source state has \emph{more} entropy of entanglement.Comment: Latex, 9 pages, 1 figur
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