Geometric phase in quantum open systems

The cornerstone of that investigations is the idea of Armin Uhlmann who gave a first mathematical formulation of the geometric phase for systems described by mixed states. Today this idea has either been modified or replaced by a new one in order to get the phase of a clear experimental meaning

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Teleportation (Kefitzat Haderech, Tay al-Arz) is one of the best known entanglement-based communication protocols. Recent experiments made by Zeilinger's group ( allowed for an effective teleportation between Canarian islands Tenerifa and La Palma. Quantum bits was sent via air. There is a necessity to estimate the quality of information transfer in the presence of decoherence.

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Quantum bits

Quantum rings are very attractive systems in context of quantum computing. Two characteristic properties: ground state persistent current and orbital magnetic moment allows defining a quantum bits on theese degrees of freedom. The potential application of quantum rings in developing quantum computers depends on its resistance to decoherence and relaxation. We address this problem and compare relaxation in quatum dots and quantum rings.

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Quantum-classical hybrids

Nanophysics operates somewhere between quantum and classical world. It is terra incognita requiring subtle mathods. Our aim is to find an effective description of quantum-classical hybrids and their properties

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Spin-boson model

Rabi model is the most fundamental model of an matter-light interaction. We investigate selected properties of that model (and its generalizations) focusing on its new symmetries and resulting new conserved quantities.

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Non-classical quantum states

All the quantum states are ex vi termini non-classical. However, there are some states which are more non-classical than the other. Schroedinger cats or various types of squeezed states can serve as a celebrated examples. We investigate both fundamantal aspects of such states and their possible realizations utilizing nanosystems

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Quantum correlations

Quantum correlations (entanglement or that qualified by quantum discord) is basis of quantum information science as they can serve as a resource for various communication protocols: coding, cryptography, teleportaion etc. Our primary aim is to consider behaviour of various types of quantum correlations affected by thermal and non-thermal environments.

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