Study of shear viscosity of SU (2)-gluodynamics within lattice simulation

This paper is devoted to the study of two-point correlation function of the energy-momentum tensor T_{12}T_{12} for SU(2)-gluodynamics within lattice simulation of QCD. Using multilevel algorithm we carried out the measurement of the correlation function at the temperature T/T_c = 1.2. It is shown that lattice data can be described by spectral functions which interpolate between hydrodynamics at low frequencies and asymptotic freedom at high frequencies. The results of the study of spectral functions allowed us to estimate the ratio of shear viscosity to the entropy density {\eta}/s = 0.134 +- 0.057.Comment: 7 pages, 3 figure

Many-body effects in graphene beyond the Dirac model with Coulomb interaction

This paper is devoted to development of perturbation theory for studying the properties of graphene sheet of finite size, at nonzero temperature and chemical potential. The perturbation theory is based on the tight-binding Hamiltonian and arbitrary interaction potential between electrons, which is considered as a perturbation. One-loop corrections to the electron propagator and to the interaction potential at nonzero temperature and chemical potential are calculated. One-loop formulas for the energy spectrum of electrons in graphene, for the renormalized Fermi velocity and also for the dielectric permittivity are derived.Comment: 11 pages, 11 figure

Quantum Monte Carlo study of static potential in graphene

In this paper the interaction potential between static charges in suspended graphene is studied within the quantum Monte Carlo approach. We calculated the dielectric permittivity of suspended graphene for the set of temperatures and extrapolated our results to zero temperature. The dielectric permittivity at zero temperature has the following properties. At zero distance $\epsilon=2.24\pm0.02$. Then it rises and at a large distance the dielectric permittivity reaches the plateau $\epsilon\simeq4.20\pm0.66$. The results obtained in this paper allow to draw a conclusion that full account of many-body effects in the dielectric permittivity of suspended graphene gives $\epsilon$ very close to the one-loop results. Contrary to the one-loop result, the two-loop prediction for the dielectric permittivity deviates from our result. So, one can expect large higher order corrections to the two-loop prediction for the dielectric permittivity of suspended graphene.Comment: 6 pages, 2 figure

ЦИТОГЕНЕТИЧЕСКИЙ СТАТУС БОЛЬНЫХ РАКОМ ЖЕЛУДКА

The aim was to identify cytogenetic disorders, proliferative activity and apoptosis in cells exfoliated buccal and nasal epithelium in patients with gastric cancer. The study involved 10 patients with an established diagnosis. The control group included 30 healthy people. It has been revealed that all this parameters were increased in buccal and nasal epithelium in patients with gastric cancer than in healthy people. The detected changes are systemic in nature and reflect the overall condition of the body. Moreover, we show reduction of karyological parameters after radical treatment, which indicates their prognostic significance.Целью было выявление цитогенетических нарушений, нарушений пролиферативной активности клеток и апоптоза в эксфолиативных клетках буккального и назального эпителия у больных с впервые диагностированным раком желудка. Обследовано 10 пациентов с установленными диагнозами. В группу контроля вошли 30 условно здоровых людей. Показано увеличение доли клеток с цитогенетическими нарушениями в буккальном и назальном эпителии у больных раком желудка по сравнению со здоровыми. Выявленные изменения носят системный характер и отражают общее состояние организма. Кроме того, показано снижение уровня кариологических показателей после радикального лечения, что свидетельствует об их прогностическом значении.

Lattice study of thermodynamic properties of dense QC2D

In this paper we study thermodynamic properties of dense cold SU(2) QCD within lattice simulation with dynamical rooted staggered quarks which in the continuum limit correspond to Nf=2 quark flavours. We calculate baryon density, renormalized chiral and diquark condensates for various baryon chemical potentials in the region μ∈(0,2000)  MeV. It is found that in the region μ∈(0,540)  MeV the system is well described by the ChPT predictions. In the region μ>540  MeV the system becomes sufficiently dense and ChPT is no longer applicable to describe lattice data. For chemical potentials μ>900  MeV we observe formation of the Fermi sphere, and the system is similar to the one described by the Bardeen-Cooper-Schrieffer theory where the diquarks play a role of Cooper pairs. In order to study how nonzero baryon density influences the gluon background we calculate chromoelectric and chromomagnetic fields, as well as the topological susceptibility. We find that the chromoelectric field and the topological susceptibility decrease, whereas the chromomagnetic field increases with rising of baryon chemical potential. Finally we study the equation of state of dense two-color quark matter

Lattice Study of QCD Properties under Extreme Conditions: Temperature, Density, Rotation, and Magnetic Field

This paper is devoted to the study of QCD properties under extreme conditions which is carried out within lattice simulations. In particular, the QCD phase diagram in external magnetic field and nonzero baryonic density is studied. In addition, the equation of state of dense quark–gluon matter which is affected by strong magnetic field is calculated. Finally, we perform lattice simulations of rotating gluodynamics and determine how rotation influences the confinement/deconfinement transition