Физика низких температур, 2015, № 05
http://dspace.nbuv.gov.ua:80/handle/123456789/121902
2020-01-24T18:51:54ZConformal phase transition: QCD like theories with a large number of fermion flavors and all that
http://dspace.nbuv.gov.ua:80/handle/123456789/122086
Conformal phase transition: QCD like theories with a large number of fermion flavors and all that
Miransky, V.A.
The notion of the conformal phase transiton (CPhT) is discussed. As its realization, the dynamics with an infrared stable fixed point in the conformal window in QCD like theories with a relatively large number of fermion flavors is reviewed. The emphasis is on the description of a clear signature for the conformal window, which in particular can be useful for lattice computer simulations of these gauge theories. A possibility of the relevance of the CPhT in graphene is mentioned.
2015-01-01T00:00:00ZThe theory of nonequilibrium Anderson impurity model for strongly correlated electron systems
http://dspace.nbuv.gov.ua:80/handle/123456789/122085
The theory of nonequilibrium Anderson impurity model for strongly correlated electron systems
Moskalenko, V.A.; Dohotaru, L.A.; Digor, D.F.
The nonequilibrium theory of strongly correlated systems is proposed theory which is grounded on the generalized Wick theorem. This theorem is employed for calculation of the thermal averages of the contour arranged products of electron operators by generalizing Keldysh formalism. Perturbation expansion is realized for Anderson impurity model in which we consider the Coulomb interaction of the impurity electrons as a main parameter of the model and the mixing interaction between impurity and conduction electrons as a perturbation. The first two approximations are used and is obtained the value of the current between one of the leads and central region of interacting electrons. The contribution of the strong correlations and of irreducible diagrams is analyzed.
2015-01-01T00:00:00ZElectronic and magnetic properties of graphite quantum dots
http://dspace.nbuv.gov.ua:80/handle/123456789/122084
Electronic and magnetic properties of graphite quantum dots
Abdelsalam, H.; Espinosa-Ortega, T.; Luk’yanchuk, I.
We study the electronic and magnetic properties of multilayer quantum dots (MQDs) of graphite in the nearest-neighbor approximation of tight-binding model. We calculate the electronic density of states and orbital susceptibility of the system as function of the Fermi level location. We demonstrate that properties of MQD depend strongly on the shape of the system, on the parity of the layer number and on the form of the cluster edge. The special emphasis is given to reveal the new properties with respect to the monolayer graphene quantum dots. The most interesting results are obtained for the triangular MQD with zig-zag edge at near-zero energies. The asymmetrically smeared multipeak feature is observed at Dirac point within the size-quantized energy gap region, where monolayer graphene flakes demonstrate the highly-degenerate zero-energy state. This feature, provided by the edge-localized electronic states results in the splash-wavelet behavior in diamagnetic orbital susceptibility as function of energy.
2015-01-01T00:00:00ZElectronic spectrum of atomic chain with Fano-Anderson impurities
http://dspace.nbuv.gov.ua:80/handle/123456789/122083
Electronic spectrum of atomic chain with Fano-Anderson impurities
Skrypnyk, Y.V.
Electronic spectrum of one-dimensional system with a low concentration of weakly bound Fano-Anderson impurities is considered. It is assumed that the energy of the impurity resonance is located in a vicinity of the band center of the host system. It is demonstrated that with increasing the impurity concentration the dispersion of states with the low damping undergoes a transformation. This transformation passes in a threshold manner and results in the reproduction of some characteristic features inherent in the cross-type spectrum rearrangement. At that, the density of states at the energy of the impurity resonance manifests a steady growth.
2015-01-01T00:00:00Z