60,040 research outputs found
Mutual information on the fuzzy sphere
We numerically calculate entanglement entropy and mutual information for a
massive free scalar field on commutative (ordinary) and noncommutative (fuzzy)
spheres. We regularize the theory on the commutative geometry by discretizing
the polar coordinate, whereas the theory on the noncommutative geometry
naturally posseses a finite and adjustable number of degrees of freedom. Our
results show that the UV-divergent part of the entanglement entropy on a fuzzy
sphere does not follow an area law, while the entanglement entropy on a
commutative sphere does. Nonetheless, we find that mutual information (which is
UV-finite) is the same in both theories. This suggests that nonlocality at
short distances does not affect quantum correlations over large distances in a
free field theory.Comment: 16 pages, 10 figures. Fixed minor typos, references updated,
discussion slightly expande
Applying the structural equation model rule-based fuzzy system with genetic algorithm for trading in currency market
The present study uses the structural equation model (SEM) to analyze the correlations between various economic indices pertaining to latent variables, such as the New Taiwan Dollar (NTD) value, the United States Dollar (USD) value, and USD index. In addition, a risk factor of volatility of currency returns is considered to develop a risk-controllable fuzzy inference system. The rational and linguistic knowledge-based fuzzy rules are established based on the SEM model and then optimized using the genetic algorithm. The empirical results reveal that the fuzzy logic trading system using the SEM indeed outperforms the buy-and-hold strategy. Moreover, when considering the risk factor of currency volatility, the performance appears significantly better. Remarkably, the trading strategy is apparently affected when the USD value or the volatility of currency returns shifts into either a higher or lower state.Knowledge-based Systems, Fuzzy Sets, Structural Equation Model (SEM), Genetic Algorithm (GA), Currency Volatility
Quantum to classical transition via fuzzy measurements on high gain spontaneous parametric down-conversion
We consider the high gain spontaneous parametric down-conversion in a non
collinear geometry as a paradigmatic scenario to investigate the
quantum-to-classical transition by increasing the pump power, that is, the
average number of generated photons. The possibility of observing quantum
correlations in such macroscopic quantum system through dichotomic measurement
will be analyzed by addressing two different measurement schemes, based on
different dichotomization processes. More specifically, we will investigate the
persistence of non-locality in an increasing size n/2-spin singlet state by
studying the change in the correlations form as increases, both in the
ideal case and in presence of losses. We observe a fast decrease in the amount
of Bell's inequality violation for increasing system size. This theoretical
analysis is supported by the experimental observation of macro-macro
correlations with an average number of photons of about 10^3. Our results
enlighten the practical extreme difficulty of observing non-locality by
performing such a dichotomic fuzzy measurement.Comment: 15 pages, 18 figure
Using Qualitative Hypotheses to Identify Inaccurate Data
Identifying inaccurate data has long been regarded as a significant and
difficult problem in AI. In this paper, we present a new method for identifying
inaccurate data on the basis of qualitative correlations among related data.
First, we introduce the definitions of related data and qualitative
correlations among related data. Then we put forward a new concept called
support coefficient function (SCF). SCF can be used to extract, represent, and
calculate qualitative correlations among related data within a dataset. We
propose an approach to determining dynamic shift intervals of inaccurate data,
and an approach to calculating possibility of identifying inaccurate data,
respectively. Both of the approaches are based on SCF. Finally we present an
algorithm for identifying inaccurate data by using qualitative correlations
among related data as confirmatory or disconfirmatory evidence. We have
developed a practical system for interpreting infrared spectra by applying the
method, and have fully tested the system against several hundred real spectra.
The experimental results show that the method is significantly better than the
conventional methods used in many similar systems.Comment: See http://www.jair.org/ for any accompanying file
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Variable grouping in multivariate time series via correlation
The decomposition of high-dimensional multivariate time series (MTS) into a number of low-dimensional MTS is a useful but challenging task because the number of possible dependencies between variables is likely to be huge. This paper is about a systematic study of the “variable groupings” problem in MTS. In particular, we investigate different methods of utilizing the information regarding correlations among MTS variables. This type of method does not appear to have been studied before. In all, 15 methods are suggested and applied to six datasets where there are identifiable mixed groupings of MTS variables. This paper describes the general methodology, reports extensive experimental results, and concludes with useful insights on the strength and weakness of this type of grouping metho
Do quantum states evolve? Apropos of Marchildon's remarks
Marchildon's (favorable) assessment (quant-ph/0303170, to appear in Found.
Phys.) of the Pondicherry interpretation of quantum mechanics raises several
issues, which are addressed. Proceeding from the assumption that quantum
mechanics is fundamentally a probability algorithm, this interpretation
determines the nature of a world that is irreducibly described by this
probability algorithm. Such a world features an objective fuzziness, which
implies that its spatiotemporal differentiation does not "go all the way down".
This result is inconsistent with the existence of an evolving instantaneous
state, quantum or otherwise.Comment: To appear in Foundations of Physics; 22 pages, LaTe
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