9,286 research outputs found
Temperature dependence of the axial magnetic effect in two-color quenched QCD
The Axial Magnetic Effect is the generation of an equilibrium dissipationless
energy flow of chiral fermions in the direction of the axial (chiral) magnetic
field. At finite temperature the dissipationless energy transfer may be
realized in the absence of any chemical potentials. We numerically study the
temperature behavior of the Axial Magnetic Effect in quenched SU(2) lattice
gauge theory. We show that in the confinement (hadron) phase the effect is
absent. In the deconfinement transition region the conductivity quickly
increases, reaching the asymptotic behavior in a deep deconfinement
(plasma) phase. Apart from an overall proportionality factor, our results
qualitatively agree with theoretical predictions for the behavior of the energy
flow as a function of temperature and strength of the axial magnetic field.Comment: 5 pages, 1 figur
Phase structure of electroweak vacuum in a strong magnetic field: the lattice results
Using first-principle lattice simulations, we demonstrate that in the
background of a strong magnetic field (around 10^{20} T), the electroweak
sector of the vacuum experiences two consecutive crossover transitions
associated with dramatic changes in the zero-temperature dynamics of the vector
W bosons and the scalar Higgs particles, respectively. Above the first
crossover, we observe the appearance of large, inhomogeneous structures
consistent with a classical picture of the formation of W and Z condensates
pierced by vortices. The presence of the W and Z condensates supports the
emergence of the exotic superconducting and superfluid properties induced by a
strong magnetic field in the vacuum. We find evidence that the vortices form a
disordered solid or a liquid rather than a crystal. The second transition
restores the electroweak symmetry. Such conditions can be realized in the
near-horizon region of the magnetized black holes.Comment: 10 page
Inhomogeneity of rotating gluon plasma and Tolman-Ehrenfest law in imaginary time: lattice results for fast imaginary rotation
We present the results of first-principle numerical simulations of Euclidean
SU(3) Yang-Mills plasma rotating with a high imaginary angular frequency. The
rigid Euclidean rotation is introduced via ``rotwisted'' boundary conditions
along imaginary time direction. The Polyakov loop in the co-rotating Euclidean
reference frame shows the emergence of a spatially inhomogeneous
confining-deconfining phase through a broad crossover transition. A
continuation of our numerical results to Minkowski spacetime suggests that the
gluon plasma, rotating at real angular frequencies, produces a new
inhomogeneous phase possessing the confining phase near the rotation axis and
the deconfinement phase in the outer regions. The inhomogeneous phase structure
has a purely kinematic origin, rooted in the Tolman-Ehrenfest effect in a
rotating medium. We also derive the Euclidean version of the Tolman-Ehrenfest
law in imaginary time formalism and discuss two definitions of temperature at
imaginary Euclidean rotation.Comment: 12 pages, 7 figure
Generation of electric current by magnetic field at the boundary: quantum scale anomaly vs. semiclassical Meissner current
The scale (conformal) anomaly can generate an electric current near the
boundary of a system in the presence of a static magnetic field. The magnitude
of this magnetization current, produced at zero temperature and in the absence
of matter, is proportional to a beta function associated with the
renormalization of the electric charge. Using first-principle lattice
simulations, we investigate how the breaking of the scale symmetry affects this
``scale magnetic effect'' near a Dirichlet boundary in scalar QED (Abelian
Higgs model). We demonstrate the interplay of the generated current with vortex
excitations both in symmetric (normal) and broken (superconducting) phases and
compare the results with the anomalous current produced in the conformal,
scale-invariant regime.Comment: 12 pages, 12 figure
Lattice QCD at finite baryon density using analytic continuation
We simulate lattice QCD with two flavors of Wilson fermions at imaginary
baryon chemical potential. Results for the baryon number density computed in
the confining and deconfining phases at imaginary baryon chemical potential are
used to determine the baryon number density and higher cumulants at the real
chemical potential via analytical continuation.Comment: 8 pages, 8 figures, Contribution to ICNFP2017, to be published in EPJ
Web of Conference
A new look at the cosmic ray positron fraction
The positron fraction in cosmic rays was found to be a steadily increasing in
function of energy, above 10 GeV. This behaviour contradicts standard
astrophysical mechanisms, in which positrons are secondary particles, produced
in the interactions of primary cosmic rays during the propagation in the
interstellar medium. The observed anomaly in the positron fraction triggered a
lot of excitement, as it could be interpreted as an indirect signature of the
presence of dark matter species in the Galaxy. Alternatively, it could be
produced by nearby astrophysical sources, such as pulsars. Both hypotheses are
probed in this work in light of the latest AMS-02 positron fraction
measurements. The transport of the primary and secondary positrons in the
Galaxy is described using a semi-analytic two-zone model. MicrOMEGAs is used to
model the positron flux generated by dark matter species. The description of
the positron fraction from astrophysical sources is based on the pulsar
observations included in the ATNF catalogue. We find that the mass of the
favoured dark matter candidates is always larger than 500 GeV. The only dark
matter species that fulfils the numerous gamma ray and cosmic microwave
background bounds is a particle annihilating into four leptons through a light
scalar or vector mediator, with a mixture of tau (75%) and electron (25%)
channels, and a mass between 0.5 and 1 TeV. The positron anomaly can also be
explained by a single astrophysical source and a list of five pulsars from the
ATNF catalogue is given. Those results are obtained with the cosmic ray
transport parameters that best fit the B/C ratio. Uncertainties in the
propagation parameters turn out to be very significant. In the WIMP
annihilation cross section to mass plane for instance, they overshadow the
error contours derived from the positron data.Comment: 20 pages, 16 figures, accepted for publication in A&A, corresponds to
published versio
Researches and grounds of design of pharmaceutical development and industrial introduction of production of parenteral preparations on the basis of recombinant proteins
In the conditions of introduction of the proper practice of production of medicinal facilities on pharmaceutical enterprises in Ukraine, it is necessary to develop effective measures of projects management for creation of favourable conditions for modernisation of pharmaceutical production, innovative management and management of development projects. The optimization of pharmaceutical production of injection preparations, modernisation of the pharmaceutical industries, is being implemented in accordance with the standards of GM
A rotating cavity for high-field angle-dependent microwave spectroscopy of low-dimensional conductors and magnets
The cavity perturbation technique is an extremely powerful method for
measuring the electrodynamic response of a material in the millimeter- and
sub-millimeter spectral range (10 GHz to 1 THz), particularly in the case of
high-field/frequency magnetic resonance spectroscopy. However, the application
of such techniques within the limited space of a high-field magnet presents
significant technical challenges. We describe a 7.62 mm x 7.62 mm (diameter x
length) rotating cylindrical cavity which overcomes these problems.Comment: 11 pages including 8 figure
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