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/ I. . Rotter, A. F. Sadreev // Int. J. Theor. Phys. - 2007. - Vol. 46: 25th International Colloquium on Group Theoretical Methods in Physics (AUG 02-06, 2004, Cocoyoc, MEXICO), Is. 8. - P. 1914-1928, DOI 10.1007/s10773-006-9328-4. - Cited References: 38 . - ISSN 0020-7748РУБ Physics, Multidisciplinary

Аннотация: The S matrix theory with use of the effective Hamiltonian is sketched and applied to the description of the transmission through double quantum dots. The effective Hamilton operator is non-hermitian, its eigenvalues are complex, the eigenfunctions are bi-orthogonal. In this theory, singularities occur at points where two (or more) eigenvalues of the effective Hamiltonian coalesce. These points are physically meaningful: they separate the scenario of avoided level crossings from that without any crossings in the complex plane. They are branch points in the complex plane. Their geometrical features are different from those of the diabolic points.

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Держатели документа:
Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden
ИФ СО РАН
Max-Planck-Institut fur Physik Komplexer Systeme, D-01187 Dresden, Germany
Kirensky Institute of Physics, Krasnoyarsk 660036, Russian Federation
Department of Physics and Measurement Technology, Linkoping University, S-58183 Linkoping, Sweden

Доп.точки доступа:
Sadreev, A. F.; Садреев, Алмаз Фаттахович

/ A. F. Sadreev, K. F. Berggren // J. Phys. A. - 2005. - Vol. 38, Is. 49. - P. 10787-10804, DOI 10.1088/0305-4470/38/49/019. - Cited References: 103 . - ISSN 0305-4470РУБ Physics, Multidisciplinary + Physics, Mathematical

Аннотация: We discuss signatures of quantum chaos in open chaotic billiards. Solutions for such a system are given by complex scattering wavefunctions psi = u + iv when a steady current flows through the billiard. For slightly opened chaotic billiards the current distributions are simple and universal. It is remarkable that the resonant transmission through integrable billiards also gives the universal current distribution. Cur-rents induced by the Rashba spin-orbit interaction can flow even in closed billiards. Wavefunction and current distributions for a chaotic billiard with weak and strong spin-orbit interactions have been derived and compared with numerics. Similarities with classical waves are considered. In particular we propose that the networks of electric resonance RLC circuits may be used to study wave chaos. However, being different from quantum billiards, there is a resistance from the inductors which gives rise to heat power and decoherence.

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Держатели документа:
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden
ИФ СО РАН
Kirensky Institute of Physics, 660036 Krasnoyarsk, Russian Federation
Department of Physics and Measurement Technology, Linkoping University, SE-581 83 Linkoping, Sweden

Доп.точки доступа:
Berggren, K. F.; Садреев, Алмаз Фаттахович

/ I. . Rotter, A. F. Sadreev // Phys. Rev. E. - 2005. - Vol. 71, Is. 3. - Ст. 36227, DOI 10.1103/PhysRevE.71.036227. - Cited References: 49 . - ISSN 1063-651XРУБ Physics, Fluids & Plasmas + Physics, Mathematical

Аннотация: We study the spectrum of an open double quantum dot as a function of different system parameters in order to receive information on the geometric phases of branch points in the complex plane (BPCP). We relate them to the geometrical phases of the diabolic points (DPs) of the corresponding closed system. The double dot consists of two single dots and a wire connecting them. The two dots and the wire are represented by only a single state each. The spectroscopic values follow from the eigenvalues and eigenfunctions of the Hamiltonian describing the double dot system. They are real when the system is closed, and complex when the system is opened by attaching leads to it. The discrete states as well as the narrow resonance states avoid crossing. The DPs are points within the avoided level crossing scenario of discrete states. At the BPCP, width bifurcation occurs. Here, different Riemann sheets evolve and the levels do not cross anymore. The BPCP are physically meaningful. The DPs are unfolded into two BPCP with different chirality when the system is opened. The geometric phase that arises by encircling the DP in the real plane, is different from the phase that appears by encircling the BPCP. This is found to be true even for a weakly opened system and the two BPCP into which the DP is unfolded.

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Держатели документа:
Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden
Astafev Krasnoyarsk Pedag Univ, Krasnoyarsk 660049, Russia
ИФ СО РАН
Max-Planck-Inst. Physik Komplexer S., D-01187 Dresden, Germany
Kirensky Institute of Physics, 660036, Krasnoyarsk, Russian Federation
Dept. of Physics and Measurement, Technology Linkoping University, S-581 83 Linkoping, Sweden
Astafev Krasnoyarsk Pedagogical U., 660049 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Sadreev, A. F.; Садреев, Алмаз Фаттахович

/ A. F. Sadreev, E. N. Bulgakov, I. . Rotter // JETP Letters. - 2005. - Vol. 82, Is. 8. - P. 498-503, DOI 10.1134/1.2150869. - Cited References: 32 . - ISSN 0021-3640РУБ Physics, Multidisciplinary

Аннотация: We consider single-channel transmission through a double quantum dot that consists of two identical single dots coupled by a wire. The numerical solution for the scattering wave function shows that the resonance width of a few of the states may vanish when the width (or length) of the wire and the energy of the incident particle each take a certain value. In such a case, a particle is trapped inside the wire as the numerical visualization of the scattering wave function shows. To understand these numerical results, we explore a simple model with a small number of states, which allows us to consider the problem analytically. If the eigenenergies of the closed system cross the energies of the transmission zeroes, the wire effectively decouples from the rest of the system and traps the particle. (C) 2005 Pleiades Publishing, Inc.

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Держатели документа:
Russian Acad Sci, Inst Phys, Krasnoyarsk 660036, Russia
Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden
Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
ИФ СО РАН
Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, 660036, Russian Federation
Department of Physics and Measurement Technology, Linkoping University, S-58183 Linkoping, Sweden
Max-Planck-Institut fur Physik Komplexer Systeme, D-01187 Dresden, Germany

Доп.точки доступа:
Bulgakov, E. N.; Булгаков, Евгений Николаевич; Rotter, I.; Садреев, Алмаз Фаттахович

/ I. . Rotter, A. F. Sadreev // Phys. Rev. E. - 2004. - Vol. 69, Is. 6. - Ст. 66201, DOI 10.1103/PhysRevE.69.066201. - Cited References: 25 . - ISSN 1539-3755РУБ Physics, Fluids & Plasmas + Physics, Mathematical

Аннотация: We consider single-channel transmission through a double quantum dot system consisting of two single dots that are connected by a wire and coupled each to one lead. The system is described in the framework of the S matrix theory by using the effective Hamiltonian of the open quantum system. It consists of the Hamiltonian of the closed system (without attached leads) and a term that accounts for the coupling of the states via the continuum of propagating modes in the leads. This model allows one to study the physical meaning of branch points in the complex plane. They are points of coalesced eigenvalues and separate the two scenarios with avoided level crossings and without any crossings in the complex plane. They influence strongly the features of transmission through double quantum dots.

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Держатели документа:
Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Linkoping Univ, Dept Phys & Measurement, S-58183 Linkoping, Sweden
Astafev Kransnoyarsk Pedag Univ, Krasnoyarsk 660049, Russia
ИФ СО РАН
Max-Planck-Inst. Phys. Komplexer S., D-01187 Dresden, Germany
Kirensky Institute of Physics, Krasnoyarsk, 660036, Russian Federation
Department of Physics, Linkoping University, S-581 83 Linkoping, Sweden
Astaf'ev Krasnoyarsk Pedagogical U., 89 Lebedeva, Krasnoyarsk, 660049, Russian Federation

Доп.точки доступа:
Sadreev, A. F.; Садреев, Алмаз Фаттахович

/ G. A. Luna-Acosta [et al.] // Phys. Rev. E. - 2002. - Vol. 65, Is. 4. - Ст. 46605, DOI 10.1103/PhysRevE.65.046605. - Cited References: 47 . - ISSN 1539-3755РУБ Physics, Fluids & Plasmas + Physics, Mathematical

Аннотация: The purely classical counterpart of the scattering probability matrix (SPM) \S(n,m)\(2) of the quantum scattering matrix S is defined for two-dimensional quantum waveguides for an arbitrary number of propagating modes M. We compare the quantum and classical structures of \S(n,m)\(2) for a waveguide with generic Hamiltonian chaos. It is shown that even for a moderate number of channels, knowledge of the classical structure of the SPM allows us to predict the global structure of the quantum one and, hence, understand important quantum transport properties of waveguides in terms of purely classical dynamics. It is also shown that the SPM, being an intensity measure, can give additional dynamical information to that obtained by the Poincare maps.

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Держатели документа:
Univ Autonoma Puebla, Inst Fis, Puebla 72570, Mexico
Univ Hradec Kralove, Dept Phys, Hradec Kralove, Czech Republic
Acad Sci Czech Republ, Inst Phys, Prague, Czech Republic
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Instituto de Fisica, Univ. Autonoma de Puebla, Apartado Postal J-48, Puebla 72570, Mexico
Department of Physics, University Haradec Kralove, Hradec Kralove, Czech Republic
Institute of Physics, Czech Academy of Sciences, Cukrovarnicka 10, Prague, Czech Republic
Kirensky Institute of Physics, 660036 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Luna-Acosta, G. A.; Mendez-Bermudez, J. A.; Seba, P.; Pichugin, K. N.; Пичугин, Константин Николаевич

/ E. N. Bulgakov, I. . Rotter, A. F. Sadreev // Phys. Rev. E. - 2006. - Vol. 74, Is. 5. - Ст. 56204, DOI 10.1103/PhysRevE.74.056204. - Cited References: 40 . - ISSN 1539-3755РУБ Physics, Fluids & Plasmas + Physics, Mathematical

Аннотация: We consider the effective Hamiltonian of an open quantum system, its biorthogonal eigenfunctions phi(lambda), and define the value r(lambda)=(phi(lambda)parallel to phi(lambda))/ that characterizes the phase rigidity of the eigenfunctions phi(lambda). In the scenario with avoided level crossings, r(lambda) varies between 1 and 0 due to the mutual influence of neighboring resonances. The variation of r(lambda) is an internal property of an open quantum system. In the literature, the phase rigidity rho of the scattering wave function Psi(E)(C) is considered. Since Psi(E)(C) can be represented in the interior of the system by the phi(lambda), the phase rigidity rho of the Psi(E)(C) is related to the r(lambda) and therefore also to the mutual influence of neighboring resonances. As a consequence, the reduction of the phase rigidity rho to values smaller than 1 should be considered, at least partly, as an internal property of an open quantum system in the overlapping regime. The relation to measurable values such as the transmission through a quantum dot, follows from the fact that the transmission is, in any case, resonant at energies that are determined by the real part of the eigenvalues of the effective Hamiltonian. We illustrate the relation between phase rigidity rho and transmission numerically for small open cavities.

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Держатели документа:
Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden
ИФ СО РАН
Max-Planck-Institut fur Physik Komplexer Systeme, D-01187 Dresden, Germany
Kirensky Institute of Physics, 660036 Krasnoyarsk, Russian Federation
Department of Physics and Measurement, Technology Linkoping University, S-581 83 Linkoping, Sweden

Доп.точки доступа:
Rotter, I.; Sadreev, A. F.; Садреев, Алмаз Фаттахович; Булгаков, Евгений Николаевич