107,607 research outputs found
Majorana and the quasi-stationary states in Nuclear Physics
A complete theoretical model describing artificial disintegration of nuclei
by bombardment with alpha-particles, developed by Majorana as early as in 1930,
is discussed in detail alongside the basic experimental evidences that
motivated it. By following the quantum dynamics of a state resulting from the
superposition of a discrete state with a continuum one, whose interaction is
described by a given potential term, Majorana obtained (among the other
predictions) the explicit expression for the integrated cross section of the
nuclear process, which is the direct measurable quantity of interest in the
experiments. Though this is the first application of the concept of
quasi-stationary states to a Nuclear Physics problem, it seems also that the
unpublished Majorana's work anticipates by several years the related seminal
paper by Fano on Atomic Physics.Comment: latex, amsart, 13 page
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Crystal structure of xenotropic murine leukaemia virus-related virus (XMRV) ribonuclease H
RNase H (retroviral ribonuclease H) cleaves the phosphate backbone of the RNA template within an RNA/DNA hybrid to complete the synthesis of double-stranded viral DNA. In the present study we have determined the complete structure of the RNase H domain from XMRV (xenotropic murine leukaemia virus-related virus) RT (reverse transcriptase). The basic protrusion motif of the XMRV RNase H domain is folded as a short helix and an adjacent highly bent loop. Structural superposition and subsequent mutagenesis experiments suggest that the basic protrusion motif plays a role in direct binding to the major groove in RNA/DNA hybrid, as well as in establishing the co-ordination among modules in RT necessary for proper function.Molecular and Cellular Biolog
Conservation of information and the foundations of quantum mechanics
We review a recent approach to the foundations of quantum mechanics inspired
by quantum information theory. The approach is based on a general framework,
which allows one to address a large class of physical theories which share
basic information-theoretic features. We first illustrate two very primitive
features, expressed by the axioms of causality and purity-preservation, which
are satisfied by both classical and quantum theory. We then discuss the axiom
of purification, which expresses a strong version of the Conservation of
Information and captures the core of a vast number of protocols in quantum
information. Purification is a highly non-classical feature and leads directly
to the emergence of entanglement at the purely conceptual level, without any
reference to the superposition principle. Supplemented by a few additional
requirements, satisfied by classical and quantum theory, it provides a complete
axiomatic characterization of quantum theory for finite dimensional systems.Comment: 11 pages, contribution to the Proceedings of the 3rd International
Conference on New Frontiers in Physics, July 28-August 6 2014, Orthodox
Academy of Crete, Kolymbari, Cret
Quantum, consciousness and panpsychism: a solution to the hard problem
We analyze the results and implications of the combination of quantum and consciousness in terms of the recent QSC analysis. The quantum effect of consciousness is first explored. We show that the consciousness of the observer can help to distinguish the nonorthogonal states under some condition, while the usual physical measuring device without consciousness can’t. The result indicates that the causal efficacies of consciousness do exist when considering the basic quantum process. Based on this conclusion, we demonstrate that consciousness is not reducible or emergent, but a new fundamental property of matter. This provides a quantum basis for panpsychism. Furthermore, we argue that the conscious process is one kind of quantum computation process based on the analysis of consciousness time and combination problem. It is shown that a unified theory of matter and consciousness should include two parts: one is the complete quantum evolution of matter state, which includes the definite nonlinear evolution element introduced by consciousness, and the other is the psychophysical principle or corresponding principle between conscious content and matter state. Lastly, some experimental suggestions are presented to confirm the theoretical analysis of the paper
A possible quantum basis of panpsychism
We show that consciousness may violate the basic quantum principle, according to which the nonorthogonal quantum states can't be distinguished. This implies that the physical world is not causally closed without consciousness, and consciousness is a fundamental property of matter, thus provides a possible quantum basis for panpsychism
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