53 research outputs found

    Оценка эффективности применения полимерного заводнения на месторождении Х

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    Обоснован выбор полимерного заводнения, как метод увеличения нефтеотдачи пласта на Северо-Хохряковском месторождении; Выбран химический реагент для проведения полимерного заводнения на месторождении; Обоснована возможность проведения полимерного заводнения на выбранном продуктивном пласте посредством технико-экономических расчетов.The choice of polymer flooding as a method to increase oil recovery in the Severo-Khokhryakovskoye field was justified; Chemical reagent was selected for polymer flooding in the field; The possibility of carrying out polymer flooding in the selected productive formation by means of technical and economic calculations was substantiated

    Berry's Phase in the Presence of a Dissipative Medium

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    We consider the spin 1/2 model coupled to a slowly varying magnetic field in the presence of a weak damping represented by a Lindblad-form operators. We show that Berry's geometrical phase remains unaltered by the two dissipation mechanism considered. Dissipation effects are twofold: a shrinking in the modulus of the Bloch's vector, which characterizes coherence loss and a time dependent (dissipation related) precession angle. We show that the line broadening of the Fourier transformation of the components of magnetization is only due to the presence of dissipation.Comment: 19 pages, 2 figure

    Some applications of the Faddeev-Yakubovsky equations to the cold-atom physics

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    We present some recent applications of the Faddeev--Yakubovsky equations in describing atomic bound and scattering problems. We consider the scattering of a charged particle XX by atomic hydrogen with special interest in X=p,e±X=p,e^{\pm}, systems of cold bosonic molecules and the bound and scattering properties of N=3 and N=4 atomic 4^4He multimers

    Adiabatic Approximation in the Density Matrix Approach: Non-Degenerate Systems

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    We study the adiabatic limit in the density matrix approach for a quantum system coupled to a weakly dissipative medium. The energy spectrum of the quantum model is supposed to be non-degenerate. In the absence of dissipation, the geometric phases for periodic Hamiltonians obtained previously by M.V. Berry are recovered in the present approach. We determine the necessary condition satisfied by the coefficients of the linear expansion of the non-unitary part of the Liouvillian in order to the imaginary phases acquired by the elements of the density matrix, due to dissipative effects, be geometric. The results derived are model-independent. We apply them to spin 1/2 model coupled to reservoir at thermodynamic equilibrium.Comment: 24 pages (new version), accepted for publication in Physica

    Three-potential formalism for the three-body scattering problem with attractive Coulomb interactions

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    A three-body scattering process in the presence of Coulomb interaction can be decomposed formally into a two-body single channel, a two-body multichannel and a genuine three-body scattering. The corresponding integral equations are coupled Lippmann-Schwinger and Faddeev-Merkuriev integral equations. We solve them by applying the Coulomb-Sturmian separable expansion method. We present elastic scattering and reaction cross sections of the e++He^++H system both below and above the H(n=2)H(n=2) threshold. We found excellent agreements with previous calculations in most cases.Comment: 12 pages, 3 figure

    Pseudo-Supersymmetric Quantum Mechanics and Isospectral Pseudo-Hermi tian Hamiltonians

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    We examine the properties and consequences of pseudo-supersymmetry for quantum systems admitting a pseudo-Hermitian Hamiltonian. We explore the Witten index of pseudo-supersymmetry and show that every pair of diagonalizable (not necessarily Hermitian) Hamiltonians with discrete spectra and real or complex-conjugate pairs of eigenvalues are isospectral and have identical degeneracy structure except perhaps for the zero eigenvalue if and only if they are pseudo-supersymmetric partners. This implies that pseudo-supersymmetry is the basic framework for generating non-Hermitian PT-symmetric and non-PT-symmetric Hamiltonians with a real spectrum via a Darboux transformation, and shows that every diagonalizable Hamiltonian H with a discrete spectrum and real or complex-conjugate pairs of eigenvalues may be factored as H=L^# L where L is a linear operator with pseudo-adjoint L^#. In particular, this factorization applies to PT-symmetric and Hermitian Hamiltonians. The nondegenerate two-level systems provide a class of Hamiltonians that are pseudo-Hermitian. We demonstrate the implications of our general results for this class in some detail.Comment: Minor corrections, accepted for publication in Nucl. Phys.

    Electron-hydrogen scattering in Faddeev-Merkuriev integral equation approach

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    Electron-hydrogen scattering is studied in the Faddeev-Merkuriev integral equation approach. The equations are solved by using the Coulomb-Sturmian separable expansion technique. We present SS- and PP-wave scattering and reactions cross sections up to the H(n=4)H(n=4) threshold.Comment: 2 eps figure

    Elite opinion and foreign policy in post-communist Russia

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    Russian elite opinion on matters of foreign policy may be classified as ‘Liberal Westerniser’, ‘Pragmatic Nationalist’ and ‘Fundamentalist Nationalist’, terms that reflect longstanding debates about the country’s relationship with the outside world. An analysis of press statements and election manifestoes together with a programme of elite interviews between 2004 and 2006 suggests a clustering of opinion on a series of strategic issues. Liberal Westernisers seek the closest possible relationship with Europe, and favour eventual membership of the EU and NATO. Pragmatic Nationalists are more inclined to favour practical co-operation, and do not assume an identity of values or interests with the Western countries. Fundamentalist Nationalists place more emphasis on the other former Soviet republics, and on Asia as much as Europe, and see the West as a threat to Russian values as well as to its state interests. Each of these positions, in turn, draws on an identifiable set of domestic constituencies: Liberal Westernisers on the promarket political parties, Pragmatic Nationalists on the presidential administration and defence and security ministries, and Fundamentalist Nationalists on the Orthodox Church and Communists

    Accidental Degeneracy and Berry Phase of Resonant States

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    We study the complex geometric phase acquired by the resonant states of an open quantum system which evolves irreversibly in a slowly time dependent environment. In analogy with the case of bound states, the Berry phase factors of resonant states are holonomy group elements of a complex line bundle with structure group C*. In sharp contrast with bound states, accidental degeneracies of resonances produce a continuous closed line of singularities formally equivalent to a continuous distribution of "magnetic" charge on a "diabolical" circle, in consequence, we find different classes of topologically inequivalent non-trivial closed paths in parameter space.Comment: 23 pages, 2 Postscript figures, LaTex, to be published in: Group 21: Symposium on Semigroups and Quantum Irreversibility (Proc. of the XXI Int. Colloquium on Group Theoretical Methods in Physics
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