486,703 research outputs found
AB effect and Aharonov-Susskind charge non-superselection
We consider a particle in a coherent superposition of states with different
electric charge moving in the vicinity of a magnetic flux. Formally, it should
acquire a (gauge-dependent) AB relative phase between the charge states, even
for an incomplete loop. If measureable, such a geometric, rather than
topological, AB-phase would seem to break gauge invariance. Wick, Wightman and
Wigner argued that since (global) charge-dependent phase transformations are
physically unobservable, charge state superpositions are unphysical (`charge
superselection rule'). This would resolve the apparent paradox in a trivial
way. However, Aharonov and Susskind disputed this superselection rule: they
distinguished between such global charge-dependent transformations, and
transformations of the relative inter-charge phases of two particles, and
showed that the latter \emph{could} in principle be observable! Finally, the
paradox again disappears once we considers the `calibration' of the phase
measured by the Aharonov-Susskind phase detectors, as well as the phase of the
particle at its initial point. It turns out that such a detector can only
distinguish between the relative phases of two paths if their (oriented)
difference forms a loop around the flux
How does intellectual capital align with cyber security?
Purpose – To position the preservation and protection of intellectual capital as a cyber security concern. We outline the security requirements of intellectual capital to help Boards of Directors and executive management teams to understand their responsibilities and accountabilities in this respect.Design/Methodology/Approach – The research methodology is desk research. In other words, we gathered facts and existing research publications that helped us to define key terms, to formulate arguments to convince BoDs of the need to secure their intellectual capital, and to outline actions to be taken by BoDs to do so.Findings – Intellectual capital, as a valuable business resource, is related to information, knowledge and cyber security. Hence, preservation thereof is also related to cyber security governance, and merits attention from boards of directors.Implications – This paper clarifies boards of directors’ intellectual capital governance responsibilities, which encompass information, knowledge and cyber security governance.Social Implications – If boards of directors know how to embrace their intellectual capital governance responsibilities, this will help to ensure that such intellectual capital is preserved and secured.Practical Implications – We hope that boards of directors will benefit from our clarifications, and especially from the positioning of intellectual capital in cyber space.Originality/Value – This paper extends a previous paper published by Von Solms and Von Solms (2018), which clarified the key terms of information and cyber security, and the governance thereof. The originality and value is the focus on the securing of intellectual capital, a topic that has not yet received a great deal of attention from cyber security researchers
Excitation Spectrum and Correlation Functions of the Z_3-Chiral Potts Quantum Spin Chain
We study the excitation spectrum and the correlation functions of the Z_3-
chiral Potts model in the massive high-temperature phase using perturbation
expansions and numerical diagonalization. We are mainly interested in results
for general chiral angles but we consider also the superintegrable case. For
the parameter values considered, we find that the band structure of the low-
lying part of the excitation spectrum has the form expected from a
quasiparticle picture with two fundamental particles. Studying the N-dependence
of the spectrum, we confirm the stability of the second fundamental particle in
a limited range of the momentum, even when its energy becomes so high that it
lies very high up among the multiparticle scattering states. This is not a
phenomenon restricted to the superintegrable line. Calculating a
non-translationally invariant correlation function, we give evidence that it is
oscillating. Within our numerical accuracy we find a relation between the
oscillation length and the dip position of the momentum dispersion of the
lightest particle which seems to be quite independent of the chiral angles.Comment: 19 pages + 6 PostScript figures (LaTeX); BONN-TH-94-2
Mesoscopic Model for Diffusion-Influenced Reaction Dynamics
A hybrid mesoscopic multi-particle collision model is used to study
diffusion-influenced reaction kinetics. The mesoscopic particle dynamics
conserves mass, momentum and energy so that hydrodynamic effects are fully
taken into account. Reactive and non-reactive interactions with catalytic
solute particles are described by full molecular dynamics. Results are
presented for large-scale, three-dimensional simulations to study the influence
of diffusion on the rate constants of the A+CB+C reaction. In the limit of
a dilute solution of catalytic C particles, the simulation results are compared
with diffusion equation approaches for both the irreversible and reversible
reaction cases. Simulation results for systems where the volume fraction of
catalytic spheres is high are also presented, and collective interactions among
reactions on catalytic spheres that introduce volume fraction dependence in the
rate constants are studied.Comment: 9 pages, 5 figure
Two-dimensional Copolymers and Multifractality: Comparing Perturbative Expansions, MC Simulations, and Exact Results
We analyze the scaling laws for a set of two different species of long
flexible polymer chains joined together at one of their extremities (copolymer
stars) in space dimension D=2. We use a formerly constructed field-theoretic
description and compare our perturbative results for the scaling exponents with
recent conjectures for exact conformal scaling dimensions derived by a
conformal invariance technique in the context of D=2 quantum gravity. A simple
MC simulation brings about reasonable agreement with both approaches. We
analyse the remarkable multifractal properties of the spectrum of scaling
exponents.Comment: 5 page
Bargaining under Incomplete Information, Fairness, and the Hold-Up Problem
In the hold-up problem incomplete contracts cause the proceeds of relation specific investments to be allocated by ex-post bargaining. The present paper investigates the efficiency of incomplete contracts if individuals have heterogeneous preferences implying heterogeneous bargaining behavior and - equally important - preferences are private information. As the sunk investment costs can thus potentially signal preferences, they can influence beliefs and consequently bargaining outcomes. The necessities of signalling are shown to generate very strong investment incentives. These incentives are based on the desire not to reveal information that is unfavorable in the ensuing bargaining. After finding all perfect Bayesian equilibria in pure strategies, the paper derives the necessary and sufficient conditions under which it is optimal to invest and trade efficiently
Natural Fermion Hierarchies from Random Yukawa Couplings
The Standard Model of particle physics requires Yukawa matrices with
eigenval- ues that differ by orders of magnitude. We propose a novel way to
explain this fact without any small or large parameters. The mechanism is based
on the observation that products of matrices of random order one-numbers have
hierarchical spectra. The same mechanism can easily account for the
hierarchical structure of the quark mixing matrix.Comment: 9 pages. v2: Extended and improved discussion on CKM matrix.
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