Solid State Quantum Information

Physicalkineticsisthe?nalsectionofthecourseoftheoreticalphysics in its standard presentation. It stays at the boundary between g- eral theories and their applications (solid state theory, theory of gases, plasma, and so on), because the treatment of kinetic phenomena always depends on speci?c structural features of materials. On the other hand, the physical kinetics as a part of the quantum theory of macroscopic systems is far from being complete. A number of its fundamental - sues, such as the problem of irreversibility and mechanisms of chaotic responses, are now attracting considerable attention. Other important sections, for example, kinetic phenomena in disordered and/or strongly non-equilibrium systems and, in particular, phase transitions in these systems, are currently under investigation. The quantum theory of m- surements and quantum information processing actively developing in the last decade are based on the quantum kinetic theory. Because a deductive theoretical exposition of the subject is not c- venient, the authors restrict themselves to a lecture-style presentation. Now the physical kinetics seems to be at the stage of development when, according to Newton, studying examples is more instructive than lea- ing rules. In view of these circumstances, the methods of the kinetic theory are presented here not in a general form but as applications for description of speci?c systems and treatment of particular kinetic p- nomena. The quantum features of kinetic phenomena can arise for several r- sons.

Physicalkineticsisthe?nalsectionofthecourseoftheoreticalphysics in its standard presentation. It stays at the boundary between g- eral theories and their applications (solid state theory, theory of gases, plasma, and so on), because the treatment of kinetic phenomena always depends on speci?c structural features of materials. On the other hand, the physical kinetics as a part of the quantum theory of macroscopic systems is far from being complete. A number of its fundamental - sues, such as the problem of irreversibility and mechanisms of chaotic responses, are now attracting considerable attention. Other important sections, for example, kinetic phenomena in disordered and/or strongly non-equilibrium systems and, in particular, phase transitions in these systems, are currently under investigation. The quantum theory of m- surements and quantum information processing actively developing in the last decade are based on the quantum kinetic theory. Because a deductive theoretical exposition of the subject is not c- venient, the authors restrict themselves to a lecture-style presentation. Now the physical kinetics seems to be at the stage of development when, according to Newton, studying examples is more instructive than lea- ing rules. In view of these circumstances, the methods of the kinetic theory are presented here not in a general form but as applications for description of speci?c systems and treatment of particular kinetic p- nomena. The quantum features of kinetic phenomena can arise for several r- sons.

The fundamental goal of physics is an understanding of the forces of nature in their simplest and most general terms. Yet there is much more involved than just a basic set of equations which eventually has to be solved when applied to specific problems. We have learned in recent years that the structure of the ground state of field theories (with which we are generally concerned) plays an equally funda­ mental role as the equations of motion themselves. Heisenberg was probably the first to recognize that the ground state, the vacuum, could acquire certain prop­ erties (quantum numbers) when he devised a theory of ferromagnetism. Since then, many more such examples are known in solid state physics, e. g. supercon­ ductivity, superfluidity, in fact all problems concerned with phase transitions of many-body systems, which are often summarized under the name synergetics. Inspired by the experimental observation that also fundamental symmetries, such as parity or chiral symmetry, may be violated in nature, it has become wide­ ly accepted that the same field theory may be based on different vacua. Practical­ ly all these different field phases have the status of more or less hypothetical models, not (yet) directly accessible to experiments. There is one magnificent ex­ ception and this is the change of the ground state (vacuum) of the electron-posi­ tron field in superstrong electric fields.