947 research outputs found

    Crystalline chiral condensates off the tricritical point in a generalized Ginzburg-Landau approach

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    We present an extensive study on inhomogeneous chiral condensates in QCD at finite density in the chiral limit using a generalized Ginzburg-Landau (GL) approach. Performing analyses on higher harmonics of one-dimensionally (1D) modulated condensates, we numerically confirm the previous claim that the solitonic chiral condensate characterized by Jacobi's elliptic function is the most favorable structure in 1D modulations. We then investigate the possibility of realization of several multidimensional modulations within the same framework. We also study the phase structure far away from the tricritical point by extending the GL functional expanded up to the eighth order in the order parameter and its spatial derivative. On the same basis, we explore a new regime in the extended GL parameter space and find that the Lifshitz point is the point where five critical lines meet at once. In particular, the existence of an intriguing triple point is demonstrated, and its trajectory consists of one of those critical lines.Comment: 17 pages, 20 eps figures; (v2) corrected an error in computation of eighth order coefficients; (v3) typos corrected, version to appear in Phys. Rev.

    Notes on projective structures and Kleinian groups

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    Throughout this paper, C will denote the complex plane, C ̂ = C ∪ {∞} the number sphere, and D = {z: |z | < 1} ⊂ C the unit disk. We use PSL(2,C) = SL(2,C) / ± id for the group of Möbius transformations of Ĉ. With Γ an arbitrary Fuchsian group, possibly having elliptic elements, let

    Predict-prevent control method for perturbed excitable systems

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    We present a control method based on two steps: prediction and prevention. For prediction we use the anticipated synchronization scheme, considering unidirectional coupling between excitable systems in a master-slave configuration. The master is the perturbed system to be controlled, meanwhile the slave is an auxiliary system which is used to predict the master's behavior. We demonstrate theoretically and experimentally that an efficient control may be achieved.Comment: 4 pages, 5 figure

    Dilatancy Behavior in Constant Strain Rate Consolidation Test

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    . Although the constant strain rate consolidation (CSRC) test appears to be one of the most promising types of rapid consolidation test, the time dependency in stress-strain response such as the secondary compression has not been sufficiently clarified yet in CSRC test. Subjected to remolded young clay, this paper shows that a lot of time dependent behavior in the standard consolidation (SC) and CSRC tests is represented systematically by a simple assumption concerning the time dependency of dilatancy. In the SC test, at the first stage of each loading step little dilatancy takes place and dilatancy begins to occur several minutes after step loading. At the latter of each loading step, dilatancy occurs proportionally with the logarithm of elapsed time, which is observed as the secondary compression. In CSRC test, some time period after the stress state has entered the normally consolidated region, dilatancy tends to occur rapidly with the increase in stress ratio. Since most of dilatancy has taken place at the earlier stage of consolidation, little dilatancy occurs at the latter stage of CSRC process. This tendency makes the specimen stiffer with the passage of time, and makes the vertical pressure and pore pressure increase substantially at the last stage of CSRC process. Consideration to such behavior may be effective to correctly interpret the result of CSRC test

    High Ratio of 44Ti/56Ni in Cas A and Axisymmetric Collapse-Driven Supernova Explosion

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    The large abundance ratio of 44Ti/56Ni^{44}Ti/^{56}Ni in Cas A is puzzling. In fact, the ratio seems to be larger than the theoretical constraint derived by Woosley & Hoffman (1991). However, this constraint is obtained on the assumption that the explosion is spherically symmetric, whereas Cas A is famous for the asymmetric form of the remnant. Recently, Nagataki et al. (1997) calculated the explosive nucleosynthesis of axisymmetrically deformed collapse-driven supernova. They reported that the ratio of 44Ti/56Ni^{44}Ti/^{56}Ni was enhanced by the stronger alpha-rich freezeout in the polar region. In this paper, we apply these results to Cas A and examine whether this effect can explain the large amount of 44Ti^{44}Ti and the large ratio of 44Ti/56Ni^{44}Ti/^{56}Ni. We demonstrate that the conventional spherically symmetric explosion model can not explain the 44^{44}Ti mass produced in Cas A if its lifetime is shorter than ∼\sim 80 years and the intervening space is transparent to the gamma-ray line from the decay of 44^{44}Ti. On the other hand, we show the axisymmetric explosion models can solve the problem. We expect the same effect from a three dimensionally asymmetric explosion, since the stronger alpha-rich freezeout will also occur in that case in the region where the larger energy is deposited.Comment: 10 pages, LaTeX text and 3 postscript figure

    Structural basis for rifamycin resistance of bacterial RNA polymerase by the three most clinically important RpoB mutations found in Mycobacterium tuberculosis

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136512/1/mmi13606.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136512/2/mmi13606_am.pd

    Scaling method for the pair-density-functional theory in combination with energy functionals satisfying the virial theorem: Checking the validity via atomic-structure calculations

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    We perform atomic-structure calculations for the neutral Ne, Mg, and Ar atoms on the basis of the recently proposed correction method (scaling method) for the pair-density (PD) -functional theory [Phys. Rev. A 84, 044502 (2011)]. The formal features of the scaling method are that the search region of PDs is substantially extended and that the resultant variationally best PD, which can be obtained without the heavy calculation tasks, satisfies the virial theorem rigorously. To enjoy the benefit of these features, we also develop the approximate form of the kinetic energy functional. It is shown by the atomic-structure calculations that the scaling method can improve well not only various energy functionals but also the spatial profiles of the electron density and exchange-correlation hole. Especially it is found that the scaling method makes preferential modifications to the energetically effective regions of the electron density and exchange-correlation hole. These results suggest that the scaling method efficiently puts the PD close to the correct ground-state PD. DOI: 10.1103/PhysRevA.87.03251

    Evolution Equation of Phenotype Distribution: General Formulation and Application to Error Catastrophe

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    An equation describing the evolution of phenotypic distribution is derived using methods developed in statistical physics. The equation is solved by using the singular perturbation method, and assuming that the number of bases in the genetic sequence is large. Applying the equation to the mutation-selection model by Eigen provides the critical mutation rate for the error catastrophe. Phenotypic fluctuation of clones (individuals sharing the same gene) is introduced into this evolution equation. With this formalism, it is found that the critical mutation rate is sometimes increased by the phenotypic fluctuations, i.e., noise can enhance robustness of a fitted state to mutation. Our formalism is systematic and general, while approximations to derive more tractable evolution equations are also discussed.Comment: 22 pages, 2 figure
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