55 research outputs found
Meaning of the wave function
We investigate the meaning of the wave function by analyzing the mass and
charge density distributions of a quantum system. According to protective
measurement, a charged quantum system has mass and charge density distributing
in space, proportional to the modulus square of its wave function. In a
realistic interpretation, the wave function of a quantum system can be taken as
a description of either a physical field or the ergodic motion of a particle.
If the wave function is a physical field, then the mass and charge density will
be distributed throughout space at a given time for a charged quantum system,
and thus there will exist gravitational and electrostatic self-interactions of
its wave function. This not only violates the superposition principle of
quantum mechanics but also contradicts experimental observations. Thus the wave
function cannot be a description of a physical field but a description of the
ergodic motion of a particle. For the later there is only a localized particle
with mass and charge at every instant, and thus there will not exist any
self-interaction for the wave function. It is further argued that the classical
ergodic models, which assume continuous motion of particles, cannot be
consistent with quantum mechanics. Based on the negative result, we suggest
that the wave function is a description of the quantum motion of particles,
which is random and discontinuous in nature. On this interpretation, the
modulus square of the wave function not only gives the density of probability
of the particle being found in certain locations, but also gives the density of
objective probability of the particle being there. We show that this new
interpretation of the wave function provides a natural realistic alternative to
the orthodox interpretation, and its implications for other realistic
interpretations of quantum mechanics are also briefly discussed.Comment: 22 page
Static forces in d=2+1 SU(N) gauge theories
Using a three-level algorithm we perform a high-precision lattice computation
of the static force up to 1fm in the 2+1 dimensional SU(5) gauge theory.
Discretization errors and the continuum limit are discussed in detail. By
comparison with existing SU(2) and SU(3) data it is found that \sigma
r_0^2=1.65-\pi/24 holds at an accuracy of 1% for all N>=2, where r_0 is the
Sommer reference scale. The effective central charge c_{eff}(r) is obtained and
an intermediate distance r_s is defined via the property c_{eff}(r_s)=\pi/24.
It separates in a natural way the short-distance regime governed by
perturbation theory from the long-distance regime described by an effective
string theory. The ratio r_s/r_0 decreases significantly from SU(2) to SU(3) to
SU(5), where r_s < r_0. We give a preliminary estimate of its value in the
large-N limit. The static force in the smallest representation of N-ality 2,
which tends to the k=2 string tension as r->oo, is also computed up to 0.7fm.
The deviation from Casimir scaling is positive and grows from 0.1% to 1% in
that range.Comment: 25 pages, 8 figures, 11 table
A model for decoherence of entangled beauty
In the context of the entangled state produced at the
resonance, we consider a modification of the usual
quantum-mechanical time evolution with a dissipative term, which contains only
one parameter denoted by and respects complete positivity. In this
way a decoherence effect is introduced in the time evolution of the 2-particle
state, which becomes stronger with increasing distance between
the two particles. While our model of time evolution has decoherence for the
2-particle system, we assume that, after the decay of one of the two B mesons,
the resulting 1-particle state obeys the purely quantum-mechanical time
evolution. From the data on dilepton events we derive an upper bound on
. We also show how is related to the so-called ``decoherence
parameter'' , which parameterizes decoherence in neutral flavoured
meson--antimeson systems.Comment: 11 pages, revtex. Two references and some comments added, version to
be published in Phys. Rev.
Decoherence of entangled kaons and its connection to entanglement measures
We study the time evolution of the entangled kaon system by considering the
Liouville - von Neumann equation with an additional term which allows for
decoherence. We choose as generators of decoherence the projectors to the
2-particle eigenstates of the Hamiltonian. Then we compare this model with the
data of the CPLEAR experiment and find in this way an upper bound on the
strength of the decoherence. We also relate to an effective
decoherence parameter considered previously in literature. Finally we
discuss our model in the light of different measures of entanglement, i.e. the
von Neumann entropy , the entanglement of formation and the concurrence
, and we relate the decoherence parameter to the loss of
entanglement: .Comment: comments and references added, 18 pages, 1 figur
Expression analysis of extracellular proteins from Phanerochaete chrysosporium grown on different liquid and solid substrates
White-rot fungi secret a large number of hydrolytic and oxidative enzymes for degradation of lignocellulosic material. The sequencing of the genome of the white-rot fungus Phanerochaete chrysosporium has facilitated the characterization of its complete extracellular proteome. P. chrysosporium was grown on liquid medium, containing glucose, cellulose or wood chips as the carbon source, and also in solid substrate fermentation bags. For liquid-grown cultures, the extracellular protein fraction was separated by 2D gel electrophoresis. Protein spots were analysed by in-gel digestion and liquid chromatography (LC)/MS/MS. A total of 18 additional protein spots from the 2D gels yielded hits from blast searches. From solid substrate cultures in which the fungus was grown in bags, the proteins were resolved by SDS-PAGE, subjected to in-gel digestion and then identified by LC/MS/MS. An additional 16 proteins yielded hits on blast searches. Enzymes involved in cellulose, hemicellulose, lignin and protein degradation were identified. Expression patterns were very similar between cellulose-grown cultures and wood-grown cultures. In addition to enzymes which act on lignocellulosic material, proteases were also found, indicating the need of fungi to scavenge for nitrogen in wood
Entanglement, Bell Inequalities and Decoherence in Particle Physics
We demonstrate the relevance of entanglement, Bell inequalities and
decoherence in particle physics. In particular, we study in detail the features
of the ``strange'' system as an example of entangled
meson--antimeson systems. The analogies and differences to entangled spin--1/2
or photon systems are worked, the effects of a unitary time evolution of the
meson system is demonstrated explicitly. After an introduction we present
several types of Bell inequalities and show a remarkable connection to CP
violation. We investigate the stability of entangled quantum systems pursuing
the question how possible decoherence might arise due to the interaction of the
system with its ``environment''. The decoherence is strikingly connected to the
entanglement loss of common entanglement measures. Finally, some outlook of the
field is presented.Comment: Lectures given at Quantum Coherence in Matter: from Quarks to Solids,
42. Internationale Universit\"atswochen f\"ur Theoretische Physik,
Schladming, Austria, Feb. 28 -- March 6, 2004, submitted to Lecture Notes in
Physics, Springer Verlag, 45 page
Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field
NONDIAGONAL NEUTRAL CURRENTS AND THE SCATTERING OF NEUTRINOS AND ANTI-NEUTRINOS BY ELECTRONS
Four general relations between neutrino and antineutrino scattering on any Ferinion target
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