4,526 research outputs found
Fermi-liquid effects in the Fulde-Ferrell-Larkin-Ovchinnikov state of two-dimensional d-wave superconductors
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 causes the magnetic spin
susceptibility to increase, which in turn leads to a reduction of the FFLO
phase. It is shown that a negative 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 CeCoIn.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
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
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
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?
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
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
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
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
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 lepton spectrum for heavy quark physics
The shape of the lepton spectrum in inclusive semileptonic decay is sensitive to matrix elements of the heavy quark
effective theory, and . From CLEO data we extract
GeV and , where
the uncertainty is the statistical error only. Systematic
uncertainties are discussed. These values for and are
used to determine and the bottom and charm quark
masses. We discuss the theoretical uncertainties related to order
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
and $\lambda_1=-0.19\pm0.10GeV^2
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