4,479 research outputs found
Using simple elastic bands to explain quantum mechanics: a conceptual review of two of Aert's machine-models
From the beginning of his research, the Belgian physicist Diederik Aerts has
shown great creativity in inventing a number of concrete machine-models that
have played an important role in the development of general mathematical and
conceptual formalisms for the description of the physical reality. These models
can also be used to demystify much of the strangeness in the behavior of
quantum entities, by allowing to have a peek at what's going on - in structural
terms - behind the "quantum scenes," during a measurement. In this author's
view, the importance of these machine-models, and of the approaches they have
originated, have been so far seriously underappreciated by the physics
community, despite their success in clarifying many challenges of quantum
physics. To fill this gap, and encourage a greater number of researchers to
take cognizance of the important work of so-called Geneva-Brussels school, we
describe and analyze in this paper two of Aerts' historical machine-models,
whose operations are based on simple breakable elastic bands. The first one,
called the spin quantum-machine, is able to replicate the quantum probabilities
associated with the spin measurement of a spin-1/2 entity. The second one,
called the \emph{connected vessels of water model} (of which we shall present
here an alternative version based on elastics) is able to violate Bell's
inequality, as coincidence measurements on entangled states can do.Comment: 15 pages, 5 figure
Modeling Concept Combinations in a Quantum-theoretic Framework
We present modeling for conceptual combinations which uses the mathematical
formalism of quantum theory. Our model faithfully describes a large amount of
experimental data collected by different scholars on concept conjunctions and
disjunctions. Furthermore, our approach sheds a new light on long standing
drawbacks connected with vagueness, or fuzziness, of concepts, and puts forward
a completely novel possible solution to the 'combination problem' in concept
theory. Additionally, we introduce an explanation for the occurrence of quantum
structures in the mechanisms and dynamics of concepts and, more generally, in
cognitive and decision processes, according to which human thought is a well
structured superposition of a 'logical thought' and a 'conceptual thought', and
the latter usually prevails over the former, at variance with some widespread
beliefsComment: 5 pages. arXiv admin note: substantial text overlap with
arXiv:1311.605
Quantum Structures: An Attempt to Explain the Origin of their Appearance in Nature
We explain the quantum structure as due to the presence of two effects, (a) a
real change of state of the entity under influence of the measurement and, (b)
a lack of knowledge about a deeper deterministic reality of the measurement
process. We present a quantum machine, where we can illustrate in a simple way
how the quantum structure arises as a consequence of the two mentioned effects.
We introduce a parameter epsilon that measures the size of the lack of
knowledge on the measurement process, and by varying this parameter, we
describe a continuous evolution from a quantum structure (maximal lack of
knowledge) to a classical structure (zero lack of knowledge). We show that for
intermediate values of epsilon we find a new type of structure, that is neither
quantum nor classical. We apply the model that we have introduced to situations
of lack of knowledge about the measurement process appearing in other regions
of reality. More specifically we investigate the quantum-like structures that
appear in the situation of psychological decision processes, where the subject
is influenced during the testing, and forms some of his opinions during the
testing process. Our conclusion is that in the light of this explanation, the
quantum probabilities are epistemic and not ontological, which means that
quantum mechanics is compatible with a determinism of the whole.Comment: 22 pages, 8 figure
What is Quantum? Unifying Its Micro-Physical and Structural Appearance
We can recognize two modes in which 'quantum appears' in macro domains: (i) a
'micro-physical appearance', where quantum laws are assumed to be universal and
they are transferred from the micro to the macro level if suitable 'quantum
coherence' conditions (e.g., very low temperatures) are realized, (ii) a
'structural appearance', where no hypothesis is made on the validity of quantum
laws at a micro level, while genuine quantum aspects are detected at a
structural-modeling level. In this paper, we inquire into the connections
between the two appearances. We put forward the explanatory hypothesis that,
'the appearance of quantum in both cases' is due to 'the existence of a
specific form of organisation, which has the capacity to cope with random
perturbations that would destroy this organisation when not coped with'. We
analyse how 'organisation of matter', 'organisation of life', and 'organisation
of culture', play this role each in their specific domain of application, point
out the importance of evolution in this respect, and put forward how our
analysis sheds new light on 'what quantum is'.Comment: 10 page
Quantum Particles as Conceptual Entities: A Possible Explanatory Framework for Quantum Theory
We put forward a possible new interpretation and explanatory framework for
quantum theory. The basic hypothesis underlying this new framework is that
quantum particles are conceptual entities. More concretely, we propose that
quantum particles interact with ordinary matter, nuclei, atoms, molecules,
macroscopic material entities, measuring apparatuses, ..., in a similar way to
how human concepts interact with memory structures, human minds or artificial
memories. We analyze the most characteristic aspects of quantum theory, i.e.
entanglement and non-locality, interference and superposition, identity and
individuality in the light of this new interpretation, and we put forward a
specific explanation and understanding of these aspects. The basic hypothesis
of our framework gives rise in a natural way to a Heisenberg uncertainty
principle which introduces an understanding of the general situation of 'the
one and the many' in quantum physics. A specific view on macro and micro
different from the common one follows from the basic hypothesis and leads to an
analysis of Schrodinger's Cat paradox and the measurement problem different
from the existing ones. We reflect about the influence of this new quantum
interpretation and explanatory framework on the global nature and evolutionary
aspects of the world and human worldviews, and point out potential explanations
for specific situations, such as the generation problem in particle physics,
the confinement of quarks and the existence of dark matter.Comment: 45 pages, 10 figure
Quantum Experimental Data in Psychology and Economics
We prove a theorem which shows that a collection of experimental data of
probabilistic weights related to decisions with respect to situations and their
disjunction cannot be modeled within a classical probabilistic weight structure
in case the experimental data contain the effect referred to as the
'disjunction effect' in psychology. We identify different experimental
situations in psychology, more specifically in concept theory and in decision
theory, and in economics (namely situations where Savage's Sure-Thing Principle
is violated) where the disjunction effect appears and we point out the common
nature of the effect. We analyze how our theorem constitutes a no-go theorem
for classical probabilistic weight structures for common experimental data when
the disjunction effect is affecting the values of these data. We put forward a
simple geometric criterion that reveals the non classicality of the considered
probabilistic weights and we illustrate our geometrical criterion by means of
experimentally measured membership weights of items with respect to pairs of
concepts and their disjunctions. The violation of the classical probabilistic
weight structure is very analogous to the violation of the well-known Bell
inequalities studied in quantum mechanics. The no-go theorem we prove in the
present article with respect to the collection of experimental data we consider
has a status analogous to the well known no-go theorems for hidden variable
theories in quantum mechanics with respect to experimental data obtained in
quantum laboratories. For this reason our analysis puts forward a strong
argument in favor of the validity of using a quantum formalism for modeling the
considered psychological experimental data as considered in this paper.Comment: 15 pages, 4 figure
High-precision elements of double-lined spectroscopic binaries from combined interferometry and spectroscopy. Application to the beta Cephei star beta Centauri
We present methodology to derive high-precision estimates of the fundamental
parameters of double-lined spectroscopic binaries. We apply the methods to the
case study of the double-lined beta Cephei star beta Centauri. We also present
a detailed analysis of beta Centauri's line-profile variations caused by its
oscillations. We point out that a systematic error in the orbital amplitudes,
and any quantities derived from them, occurs if the radial velocities of
blended component lines are computed without spectral disentangling. This
technique is an essential ingredient in the derivation of the physical
parameters if the goal is to obtain a precision of only a few percent. We have
devised iteration schemes to obtain the orbital elements for systems whose
lines are blended throughout the orbital cycle. We find the following
parameters for beta Cen: and , an age of years. We deduce two oscillation
frequencies for the broad-lined primary of beta Centauri with degrees higher
than 2. We propose that our iteration schemes be used in any future derivations
of the spectroscopic orbital parameters of double-lined binaries with blended
component lines to which disentangling can be successfully applied.Comment: 12 pages, 13 figures, accepted for publication in A&
A Quantum-Conceptual Explanation of Violations of Expected Utility in Economics
The expected utility hypothesis is one of the building blocks of classical
economic theory and founded on Savage's Sure-Thing Principle. It has been put
forward, e.g. by situations such as the Allais and Ellsberg paradoxes, that
real-life situations can violate Savage's Sure-Thing Principle and hence also
expected utility. We analyze how this violation is connected to the presence of
the 'disjunction effect' of decision theory and use our earlier study of this
effect in concept theory to put forward an explanation of the violation of
Savage's Sure-Thing Principle, namely the presence of 'quantum conceptual
thought' next to 'classical logical thought' within a double layer structure of
human thought during the decision process. Quantum conceptual thought can be
modeled mathematically by the quantum mechanical formalism, which we illustrate
by modeling the Hawaii problem situation, a well-known example of the
disjunction effect, and we show how the dynamics in the Hawaii problem
situation is generated by the whole conceptual landscape surrounding the
decision situation.Comment: 9 pages, no figure
Collective pulsational velocity broadening due to gravity modes as a physical explanation for macroturbulence in hot massive stars
We aimed at finding a physical explanation for the occurrence of
macroturbulence in the atmospheres of hot massive stars, a phenomenon found in
observations since more than a decade but yet unexplained. We computed time
series of line profiles for evolved massive stars broadened by rotation and by
hundreds of low-amplitude nonradial gravity-mode pulsations which are predicted
to be excited for evolved massive stars. In general, line profiles based on
macrotubulent broadening can mimic those subject to pulsational broadening. In
several cases, though, good fits require macroturbulent velocities that pass
the speed of sound for realistic pulsation amplitudes. Moreover, we find that
the rotation velocity can be seriously underestimated by using a simple
parameter description for macroturbulence rather than an appropriate
pulsational model description to fit the line profiles. We conclude that
macroturbulence is a likely signature of the collective effect of pulsations.
We provide line diagnostics and their typical values to decide whether or not
pulsational broadening is present in observed line profiles, as well as a
procedure to avoid an inaccurate estimation of the rotation velocity.Comment: 12 pages, 9 figures, accepted for publication by Astronomy and
Astrophysic
Ground-based observations of the beta Cephei CoRoT main target HD 180642: abundance analysis and mode identification
The known beta Cephei star HD 180642 was observed by the CoRoT satellite in
2007. From the very high-precision light curve, its pulsation frequency
spectrum could be derived for the first time (Degroote and collaborators). In
this paper, we obtain additional constraints for forthcoming asteroseismic
modeling of the target. Our results are based on both extensive ground-based
multicolour photometry and high-resolution spectroscopy. We determine T_eff =
24 500+-1000 K and log g = 3.45+-0.15 dex from spectroscopy. The derived
chemical abundances are consistent with those for B stars in the solar
neighbourhood, except for a mild nitrogen excess. A metallicity Z =
0.0099+-0.0016 is obtained. Three modes are detected in photometry. The degree
l is unambiguously identified for two of them: l = 0 and l = 3 for the
frequencies 5.48694 1/d and 0.30818 1/d, respectively. The radial mode is
non-linear and highly dominant with an amplitude in the U-filter about 15 times
larger than the strongest of the other modes. For the third frequency of
7.36673 1/d found in photometry, two possibilities remain: l = 0 or 3. In the
radial velocities, the dominant radial mode presents a so-called stillstand but
no clear evidence of the existence of shocks is observed. Four low-amplitude
modes are found in spectroscopy and one of them, with frequency 8.4079 1/d, is
identified as (l,m)=(3,2). Based on this mode identification, we finally deduce
an equatorial rotational velocity of 38+-15 km/s.Comment: Accepted for publication in Astronomy and Astrophysic
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