Ph.D Student | Terno Daniel |
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Subject | Quantum Information and Relativity Theory |

Department | Department of Physics |

Supervisor | Mr. Asher Peres (Deceased) |

Quantum mechanics, information theory, and relativity theory are the basic foundations of theoretical physics. The acquisition of information from a quantum system is the interface of classical and quantum physics. Essential tools for its description are completely positive transformations and positive operator valued measures (POVMs). Special relativity imposes severe restrictions on the transfer of information between distant systems. Quantum entropy is not a Lorentz covariant concept. Lorentz transformations of reduced density matrices may not be completely positive maps. Degree of entanglement depends on the relative motion of the observers. Quantum field theory, which is necessary for a consistent description of interactions, implies a fundamental trade-off between detector reliability and localizability. It also provides for a much broader range of entangled states and makes a distinction between global and local operators subtler. General relativity produces new, counterintuitive effects, in particular when black holes (or more generally, event horizons) are involved. Namely, information' is supposed to be lost in creation and evaporation of black holes. We argue that black hole horizons are never `actually' formed and thus there is no information loss. Many of the current concepts in quantum information theory require reassessment when translated to the relativistic domain. We made first steps in that direction.