Bопросы атомной науки и техники, 2001
http://dspace.nbuv.gov.ua:80/xmlui/handle/123456789/74805
2024-07-24T06:47:53ZSuperfluid states with finite momentum of Cooper pairs in nuclear matter
http://dspace.nbuv.gov.ua:80/xmlui/handle/123456789/80056
Superfluid states with finite momentum of Cooper pairs in nuclear matter
Isayev, A.A.
Superﬂuid states of symmetric nuclear matter with ﬁnite total momentum of Cooper pairs (nuclear LOFF phase) are studied with the use of Fermi–liquid theory in the model with Skyrme eﬀective forces. It is considered the case of four–fold splitting of the excitation spectrum due to ﬁnite superﬂuid momentum and coupling of T = 0 and T = 1 pairing channels. It has been shown that at zero temperature the energy gap in triplet–singlet (TS) pairing channel (in spin and isospin spaces) for the SkM∗ force demonstrates double–valued behavior as a function of superﬂuid momentum. As a consequence, the phase transition at the critical superﬂuid momentum from the LOFF phase to the normal state will be of a ﬁrst order. Behavior of the energy gap as a function of density for TS pairing channel under increase of superﬂuid momentum changes from one–valued to universal two–valued. It is shown that two–gap solutions, describing superposition of states with singlet–triplet (ST) and TS pairing of nucleons appear as a result of branching from one–gap ST solution. Comparison of the free energies shows that the state with TS pairing of nucleons is thermodynamically most preferable.
2001-01-01T00:00:00ZGenerating functional in classical Hamiltonian mechanics
http://dspace.nbuv.gov.ua:80/xmlui/handle/123456789/80055
Generating functional in classical Hamiltonian mechanics
Zazunov, L.G.
We give a brief survey of a path-integral formulation of classical Hamiltonian dynamics that means a functional-integral representation of classical transition probabilities. This functional exhibits a hidden BRST and anti-BRST invariance. Therefore a simple expression, in terms of superfields, is received for the generating functional. We extend the results for discrete classical systems to continuum mechanics.
2001-01-01T00:00:00ZTwo channels of scattering of Hubbard chain electrons with spin and orbital interactions (exact results)
http://dspace.nbuv.gov.ua:80/xmlui/handle/123456789/80054
Two channels of scattering of Hubbard chain electrons with spin and orbital interactions (exact results)
Zhuravlyov, A.F.
A simple way to determine the channel of scattering of the Hubbard chain electrons with additional quantum number, which means the orbital or band characteristic, is demonstrated on the integrable 1D modified Hubbard model. Exact solutions are obtained for each scattering channel of the electrons. The preferable channel is determined by means of numerical calculations of the ground-state energies and comparison its values. The dependence of the scattering matrices on the parameters of Coulomb, orbital (band), and spin interactions gives the possibility to present the properties of the system considered in different ranges (reasonable in physics sense) of parameters which correspond to the electron coupling. The ratio between magnetic susceptibility and heat capacity of the model is presented.
2001-01-01T00:00:00Zd-electrons and superconductivity of transition metal oxides
http://dspace.nbuv.gov.ua:80/xmlui/handle/123456789/80053
d-electrons and superconductivity of transition metal oxides
Sergeeva, G.G.
Some problems of the normal state of high temperature cuprate superconductors (HTS) with d-wave pairing are discussed. It is shown that: 1) at pseudogap temperature T* it occurs the dimensional crossover of the normal incoherent state to quasi 2D system of Cu O2 layers; 2) «naked holes» are bad quasiparticles for quasi 2D system with Jahn-Teller and mixed-valent Cu ions, with strong electron correlations and fluctuations, and with inherent strong p-d hybridization of copper and oxygen orbitals. Under these circumstances the holes are reduced to two types of the magneto-elastic polarons: the ferromagnetic bound polarons, which lead to forming of the stripes state, and antiferromagnetic Jahn-Teller-Zhang-Rice polarons which can form pairs and lead to the superconductivity.
2001-01-01T00:00:00Z