Results 1 - 10 of 10175
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[en] We show that the principle of entropy increase may be exactly founded on a few axioms valid not only for quantum and classical statistics, but also for a wide range of statistical processes. (author)
[en] Recently, a number of books have appeared purporting to explain quantum mechanics to the general public. These books have put considerable emphasis on so-called quantum 'paradoxes', using them to portray the quantum theory as mysterious or 'spooky'. We discuss these 'paradoxes' from a different viewpoint with the aim of demystifying the theory. Emphasis is shifted from an epistemological viewpoint (as exemplified by the 'probability interpretation') to an ontological one (the description of matter by physical fields). Difficulties in reconciling the probability interpretation with relativity are noted, and the importance of phase coherence, which is inadequately treated in the probability interpretation, is emphasised. In the light of such an approach, the 'paradoxes' are resolved. (author)
[en] The experimental shell-model states for 20Ne nuclei are well understood. The level structure consists of 0+, 2+, 4+, 0+ etc. states. Most of our theoretical understanding of the level structure of nuclei require fitting to data a two-body interaction derived from realistic forces and using these set of data as input into a standard shell-model code to calculate the energy eigenstates of the nuclei. The set of data obtained from realistic forces usually, will not give a good description of the energy eigenstates. Using a set of two-body correlation basis functions, we have generated a set of two-body matrix elements from the Reid interaction. The matrix elements have been used to calculate the level scheme for 20Ne nuclei using the standard Glasgow shell-model code. most of the low lying level structure of 20Ne have been reproduced and results compare reasonably with experimental data
[en] Complete sets of mutually unbiased bases (MUBs) offer interesting applications in quantum information processing ranging from quantum cryptography to quantum state tomography. Different construction schemes provide different perspectives on these bases which are typically also deeply connected to various mathematical research areas. In this talk we discuss characteristic properties resulting from a recently established connection between construction methods for cyclic MUBs and Fibonacci polynomials. As a remarkable fact this connection leads to construction methods which do not involve any relations to mathematical properties of finite fields.
[en] Finite dimensional representations of extended Weyl-Heisenberg algebra are studied both from mathematical and applied viewpoints. They are used to define unitary phase operator and the corresponding eigenstates (phase states). It is also shown that the unitary depolarizers can be constructed in a general setting in terms of phase operators. Generation of generalized Bell states using the phase operator is presented and their expressions in terms of the elements of mutually unbiased bases are given. -- Highlights: → Hermitian phase operators and phase states are given for a large class of extended Weyl-Heisenberg algebras. → The unitary phase depolarizers are expressed in terms of phase operators. → The entanglement of generalized Bell states is examined.
[en] We extend the recent gravitational decoherence analysis of Pikovski et al. to an individual mesoscopic system with internal state characterized by a coherent superposition of energy eigenstates. We express the Pikovski et al. effect directly in terms of the energy variance, and show that the interferometric visibility is bounded from below. Hence unlike collisional decoherence, the visibility does not approach zero at large times, although for a large system it can become very small. - Highlights: • An extension of gravitationally induced decoherence is proposed. • The decoherence effect is conveniently expressed in terms of the energy variance. • A proof that the interferometric visibility is bounded from below is given. • The competition between gravitational and collisional decoherence is studied.