4,526 research outputs found

    Fermi-liquid effects in the Fulde-Ferrell-Larkin-Ovchinnikov state of two-dimensional d-wave superconductors

    Full text link
    We study the effects of Fermi-liquid interactions on quasi-two-dimensional d-wave superconductors in a magnetic field. The phase diagram of the superconducting state, including the periodic Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in high magnetic fields, is discussed for different strengths of quasiparticle many-body interactions within Landau's theory of Fermi liquids. Decreasing the Fermi-liquid parameter F0aF_0^a causes the magnetic spin susceptibility to increase, which in turn leads to a reduction of the FFLO phase. It is shown that a negative F0aF_0^a results in a first-order phase transition from the normal to the uniform superconducting state in a finite temperature interval. Finally, we discuss the thermodynamic implications of a first-order phase transition for CeCoIn5_5.Comment: published version; removed direct comparison with experiment for the upper critical field, as required by the referee

    Pauli-Limited Superconductivity with Classical Magnetic Fluctuations

    Get PDF
    We examine the effect of classical magnetic fluctuations on the phase diagram of paramagneticallylimited two-dimensional superconductors under a Zeeman magnetic field. We derive the free energy expansion in powers of the superconducting order parameter and analyze the character of the normalsuperconducting transition. While the transition is of the second order for all temperatures in the absence of magnetic fluctuations, we find that proximity to magnetism drives both the transition into the uniform state and that into the modulated (Fulde-Ferrell-Larkin-Ovchinnikov, FFLO) state to first order at intermediate temperatures. We compute the thermodynamic signatures of the normal-superconducting transition along the upper critical field.Comment: 16 pages, 9 figure

    Functional Classical Mechanics and Rational Numbers

    Full text link
    The notion of microscopic state of the system at a given moment of time as a point in the phase space as well as a notion of trajectory is widely used in classical mechanics. However, it does not have an immediate physical meaning, since arbitrary real numbers are unobservable. This notion leads to the known paradoxes, such as the irreversibility problem. A "functional" formulation of classical mechanics is suggested. The physical meaning is attached in this formulation not to an individual trajectory but only to a "beam" of trajectories, or the distribution function on phase space. The fundamental equation of the microscopic dynamics in the functional approach is not the Newton equation but the Liouville equation for the distribution function of the single particle. The Newton equation in this approach appears as an approximate equation describing the dynamics of the average values and there are corrections to the Newton trajectories. We give a construction of probability density function starting from the directly observable quantities, i.e., the results of measurements, which are rational numbers.Comment: 8 page

    Infra-red divergences in plane wave backgrounds

    Get PDF
    We show that the emission of soft photons via nonlinear Compton scattering in a pulsed plane wave (laser field) is in general infra-red divergent. We give examples of both soft and soft-collinear divergences, and we pay particular attention to the case of crossed fields in both classical and quantum theories.Comment: 15 pages, 7 figure

    Quantum Chemical Studies Of Nucleic Acids Can We Construct A Bridge To The Rna Structural Biology And Bioinformatics Communities?

    Get PDF
    In this feature article we provide a side-by-side introduction for two research fields quantum chemical calculations of molecular interaction in nucleic acids and RNA structural bioinformatics Our main aim is to demonstrate that these research areas while largely separated in contemporary literature have substantial potential to complement each other that could significantly contribute to our understanding of the exciting world of nucleic acids We identify research questions amenable to the combined application of modern ab initio methods and bioinformatics analysis of experimental structures while also assessing the limitations of these approaches The ultimate aim is to attain valuable physicochemical insights regarding the nature of the fundamental molecular interactions and how they shape RNA structures, dynamics, function, and evolution

    First-principles calculations of magnetization relaxation in pure Fe, Co, and Ni with frozen thermal lattice disorder

    Full text link
    The effect of the electron-phonon interaction on magnetization relaxation is studied within the framework of first-principles scattering theory for Fe, Co, and Ni by displacing atoms in the scattering region randomly with a thermal distribution. This "frozen thermal lattice disorder" approach reproduces the non-monotonic damping behaviour observed in ferromagnetic resonance measurements and yields reasonable quantitative agreement between calculated and experimental values. It can be readily applied to alloys and easily extended by determining the atomic displacements from ab initio phonon spectra

    Signatures of High-Intensity Compton Scattering

    Full text link
    We review known and discuss new signatures of high-intensity Compton scattering assuming a scenario where a high-power laser is brought into collision with an electron beam. At high intensities one expects to see a substantial red-shift of the usual kinematic Compton edge of the photon spectrum caused by the large, intensity dependent, effective mass of the electrons within the laser beam. Emission rates acquire their global maximum at this edge while neighbouring smaller peaks signal higher harmonics. In addition, we find that the notion of the centre-of-mass frame for a given harmonic becomes intensity dependent. Tuning the intensity then effectively amounts to changing the frame of reference, going continuously from inverse to ordinary Compton scattering with the centre-of-mass kinematics defining the transition point between the two.Comment: 25 pages, 16 .eps figure

    Born on 19 November 1912: he, George Palade, a man who contributed so much to the progress of modern cell biology

    Get PDF
    In his 1971 paper George Palade wrote for Albert Claude, the founder of biological electron microscopic method: “Seldom has a field owed so much to a single man”. Herein, we articulate the same words for George Palade, the Teacher of many generations in cell biology research and education. Herein we focus on the paradigm shifts in the cell biology, namely the transition from light to transmission electron microscopy in studying cell protein secretion made by George Palade. Onward, we discuss on the transition from contractile to secretory phenotype of vascular smooth muscle cells initiated by Maria Daria Haust and developed by our research group. Taken together, we argue that one of the present challenges in cell biology is to cultivate secretocentric thinking and thus further focusing on how we could make secretory pathways work for the benefit of human’s health

    X-Ray computed tomography evaluation of intramuscular fat content in Hungarian simmental cattle

    Get PDF
    Intramuscular fat content (marbling) is an economically important factor in many beef carcass classification systems. The aim of this study was to evaluate marbling of longissimus muscle with different methods (USDA marbling score, image analysis of X-ray computed tomography scans, and conventional method), moreover it was aimed to establish the relationship between marbling traits and SEUROP conformation and fat score. Bulls (n=46) were slaughtered at an average weight of 536±126 kg and an average age of 646±437 days. The average growth rate of bulls was 955 g day–1, the average chemical fat content of longissimus varied between 2.3 to 5.0% in fat classes. The intramuscular fat content on CT-scans closely correlated with chemical fat content (r=0.9). The highest frequency of USDA marbling score was “small” (55.2%), followed by “slight” (25.5%), “modest” (17%), and “moderate” (2.1%). Bulls with higher growth rate had lower CT-measured marbling traits in longissimus muscle (r = –0.4 – –0.5). The CT scans of longissimus muscle can be used for the evaluation of marbling in Hungarian Simmental cattle. The SEUROP conformation and fat score have no relationship with marbling traits

    Implications of the BXνˉB \to X \ell \bar\nu_\ell lepton spectrum for heavy quark physics

    Full text link
    The shape of the lepton spectrum in inclusive semileptonic BXνˉB\to X\,\ell\,\bar\nu_\ell decay is sensitive to matrix elements of the heavy quark effective theory, Λˉ\bar\Lambda and λ1\lambda_1. From CLEO data we extract Λˉ=0.39±0.11\bar\Lambda=0.39\pm0.11\,GeV and λ1=0.19±0.10GeV2\lambda_1=-0.19\pm0.10\,{\rm GeV}^2, where the uncertainty is the 1σ1\sigma statistical error only. Systematic uncertainties are discussed. These values for Λˉ\bar\Lambda and λ1\lambda_1 are used to determine Vcb|V_{cb}| and the MS\overline{\rm MS} bottom and charm quark masses. We discuss the theoretical uncertainties related to order (ΛQCD/mb)3(\Lambda_{\rm QCD}/m_b)^3 effects and higher orders in the perturbative expansion.Comment: 10 pages revtex + one figure. Corrections from secondary leptons included, that affect the numerical results. Thus the central values become Λˉ=0.39±0.11GeV\bar\Lambda=0.39\pm0.11GeV and $\lambda_1=-0.19\pm0.10GeV^2
    corecore