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Irkutsk, Russia

Irkutsk State University was founded in October 1918 in Irkutsk, Siberia. At present, the University consists of 10 faculties, 4 educational institutions and 2 branches. Over 18 thousand students, including 300 foreign students from 27 countries, study at University in 52 specialties, and more than 620 educators-instructors work there.The University faculties and institutions are located in 9 educational buildings in Irkutsk and in 2 buildings in Angarsk and Bratsk. The majority of these buildings are of great historical and architectural value. They date back to the 18th-19th centuries. Senior students of all the faculties have specialized courses and internship in laboratories and scientific research institutions of ISU and Siberian Branch of the Russian Academy of science.For decades, Irkutsk University has trained more than 70 thousand highly qualified specialists, famous scientists, teachers, writers, and statesmen, including Lenin and State Prize winners A. Belov, Ya. Khabardin, G. Feinstein, M. Gerasimov, G. Debetz, and famous talented writers V. Rasputin, A. Vampilov, and M. Sergeev.Irkutsk State University is the oldest higher educational institution in Eastern Siberia and the Far East.Russian scientists, statesmen, patrons of art and science, such as N.M. Yadrintsev, A.P. Shchapov, P.A. Slovtsov, S.S. Shchukin, G.N. Potanin and many others were founders of Irkutsk State University. The University was opened on October 27, 1918. It became the major educational, scientific and cultural center on the vast territory of Eastern Siberia and Far East region. During the 1930s, the University continued to grow and develop and soon in Irkutsk the first higher educational institutions emerged from it. They were Medical Institute, Pedagogical Institute and the Institute of National Economy. At present, the ISU graduates work in scientific institutions of Siberian Branch of the Russian Academy of science, Academy of Medical science, as well as they represent highly qualified personnel of teachers in higher educational institutions of Irkutsk and Siberia. Wikipedia.

Rastegin A.E.,Irkutsk State University
Quantum Information Processing | Year: 2013

Uncertainty relations for more than two observables have found use in quantum information, though commonly known relations pertain to a pair of observables. We present novel uncertainty and certainty relations of state-independent form for the three Pauli observables with use of the Tsallis α -entropies. For all real α∈ (0;1] and integer α ≥ 2, lower bounds on the sum of three α -entropies are obtained. These bounds are tight in the sense that they are always reached with certain pure states. The necessary and sufficient condition for equality is that the qubit state is an eigenstate of one of the Pauli observables. Using concavity with respect to the parameter α, we derive approximate lower bounds for non-integer α∈ (1;+\infty). In the case of pure states, the developed method also allows to obtain upper bounds on the entropic sum for real α∈ (0;1] and integer α ≥ 2. For applied purposes, entropic bounds are often used with averaging over the individual entropies. Combining the obtained bounds leads to a band, in which the rescaled average α -entropy ranges in the pure-state case. A width of this band is essentially dependent on α. It can be interpreted as an evidence for sensitivity in quantifying the complementarity. © 2013 Springer Science+Business Media New York.

Rastegin A.E.,Irkutsk State University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016

The concept of coherence is one of cornerstones in physics. The development of quantum information science has lead to renewed interest in properly approaching the coherence at the quantum level. Various measures could be proposed to quantify coherence of a quantum state with respect to the prescribed orthonormal basis. To be a proper measure of coherence, each candidate should enjoy certain properties. It seems that the monotonicity property plays a crucial role here. Indeed, there is known an intuitive measure of coherence that does not share this condition. We study coherence measures induced by quantum divergences of the Tsallis type. Basic properties of the considered coherence quantifiers are derived. Tradeoff relations between coherence and mixedness are examined. The property of monotonicity under incoherent selective measurements has to be reformulated. The proposed formulation can naturally be treated as a parametric extension of its standard form. Finally, two coherence measures quadratic in moduli of matrix elements are compared from the monotonicity viewpoint. © 2016 American Physical Society.

Rastegin A.E.,Irkutsk State University
Journal of Statistical Physics | Year: 2011

Basic properties of the unified entropies are examined. The consideration is mainly restricted to the finite-dimensional quantum case. Bounds in terms of ensembles of quantum states are given. Both the continuity in Fannes' sense and stability in Lesche's sense are shown for wide ranges of parameters. In particular, uniform estimates are obtained for the quantum Rényi entropies. Stability properties in the thermodynamic limit are discussed as well. It is shown that the unified entropies enjoy both the subadditivity and triangle inequality for a certain range of parameters. Non-decreasing of all the unified entropies under projective measurements is proved. © 2011 Springer Science+Business Media, LLC.

Rastegin A.E.,Irkutsk State University
Quantum Information and Computation | Year: 2012

Number-phase uncertainty relations are formulated in terms of unified entropies which form a family of two-parametric extensions of the Shannon entropy. For two generalized measurements, unified-entropy uncertainty relations are given in both the state-dependent and state-independent forms. A few examples are discussed as well. Using the Pegg-Barnett formalism and the Riesz theorem, we obtain a nontrivial inequality between norm-like functionals of generated probability distributions in finite dimensions. The principal point is that we take the infinite-dimensional limit right for this inequality. Hence number-phase uncertainty relations with finite phase resolutions are expressed in terms of the unified entropies. Especially important case of multiphoton coherent states is separately considered. We also give some entropic bounds in which the corresponding integrals of probability density functions are involved. © Rinton Press.

Rastegin A.E.,Irkutsk State University
Journal of Physics A: Mathematical and Theoretical | Year: 2011

A way to pose the entropic uncertainty principle for trace-preserving superoperators is presented. It is based on the notion of extremal unraveling of a super-operator. For a given input state, different effects of each unraveling result in some probability distribution at the output. As is shown, all Tsallis' entropies of positive order as well as some of Rényi's entropies of this distribution are minimized by the same unraveling of a super-operator. Entropic relations between a state ensemble and the generated density matrix are revisited in terms of both the adopted measures. Using Riesz's theorem, we obtain two uncertainty relations for any pair of generalized resolutions of the identity in terms of the Rényi and Tsallis entropies. The inequality with Rényi's entropies is an improvement of the previous one, whereas the inequality with Tsallis' entropies is a new relation of a general form. The latter formulation is explicitly shown for a pair of complementary observables in a d-level system and for the angle and angular momentum. The derived general relations are immediately applied to extremal unravelings of two super-operators. © 2011 IOP Publishing Ltd.

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