26 research outputs found
Equilibration and locality
Experiments motivated by predictions of quantum mechanics indicate
non-trivial correlations between spacelike-separated measurements. The
phenomenon is referred to as a violation of strong-locality and, after
Einstein, called ghostly action at a distance. An intriguing and previously
unasked question is how the evolution of an assembly of particles to
equilibrium-state relates to strong-locality. More specifically, whether, with
this respect, indistinguishable particles differ from distinguishable ones.
To address the question, we introduce a Markov-chain based framework over a
finite set of microstates. For the first time, we formulate conditions needed
to obey the particle transport- and strong-locality for indistinguishable
particles.
Models which obey transport-locality and lead to equilibrium-state are
considered. We show that it is possible to construct models obeying and
violating strong-locality both for indistinguishable particles and for
distinguishable ones. However, we find that only for distinguishable particles
strongly-local evolution to equilibrium is possible without breaking the
microstate-symmetry. This is the strongest symmetry one can impose and leads to
the shortest equilibration time.
We hope that the results presented here may provide a new perspective on a
violation of strong-locality, and the developed framework will help in future
studies. Specifically they may help to interpret results on high-energy nuclear
collisions indicating a fast equilibration of indistinguishable particles
Constraining baryon annihilation in the hadronic phase of heavy-ion collisions via event-by-event fluctuations
We point out that the variance of net-baryon distribution normalized by the
Skellam distribution baseline, ,
is sensitive to the possible modification of (anti)baryon yields due to
annihilation in the hadronic phase. The corresponding measurements
can thus place stringent limits on the magnitude of the annihilation
and its inverse reaction. We perform Monte Carlo simulations of the hadronic
phase in Pb-Pb collisions at the LHC via the recently developed subensemble
sampler + UrQMD afterburner and show that the effect survives in net-proton
fluctuations, which are directly accessible experimentally. The available
experimental data of the ALICE Collaboration on net-proton fluctuations
disfavors a notable suppression of (anti)baryon yields in
annihilations predicted by the present version of UrQMD if only global baryon
conservation is incorporated. On the other hand, the annihilations improve the
data description when local baryon conservation is imposed. The two effects can
be disentangled by measuring ,
which at the LHC is notably suppressed by annihilations but virtually
unaffected by baryon number conservation.Comment: 6 pages, 4 figure
Higher order conserved charge fluctuations inside the mixed phase
General formulas are presented for higher order cumulants of the conserved
charge statistical fluctuations inside the mixed phase. As a particular example
the van der Waals model in the grand canonical ensemble is used. The higher
order measures of the conserved charge fluctuations up to the hyperkurtosis are
calculated in a vicinity of the critical point (CP). The analysis includes both
the mixed phase region and the pure phases on the phase diagram. It is shown
that even-order fluctuation measures, e.g. scaled variance, kurtosis, and
hyperkurtosis, have only positive values in the mixed phase, and go to infinity
at the CP. For odd-order measures, such as skewness and hyperskewness, the
regions of positive and negative values are found near the left and right
binodals, respectively. The obtained results are discussed in a context of the
event-by-event fluctuation measurements in heavy-ion collisions.Comment: 10 pages, 3 figure
Fourier-Flow model generating Feynman paths
As an alternative but unified and more fundamental description for quantum
physics, Feynman path integrals generalize the classical action principle to a
probabilistic perspective, under which the physical observables' estimation
translates into a weighted sum over all possible paths. The underlying
difficulty is to tackle the whole path manifold from finite samples that can
effectively represent the Feynman propagator dictated probability distribution.
Modern generative models in machine learning can handle learning and
representing probability distribution with high computational efficiency. In
this study, we propose a Fourier-flow generative model to simulate the Feynman
propagator and generate paths for quantum systems. As demonstration, we
validate the path generator on the harmonic and anharmonic oscillators. The
latter is a double-well system without analytic solutions. To preserve the
periodic condition for the system, the Fourier transformation is introduced
into the flow model to approach a Matsubara representation. With this novel
development, the ground-state wave function and low-lying energy levels are
estimated accurately. Our method offers a new avenue to investigate quantum
systems with machine learning assisted Feynman Path integral solving
Molecular dynamics analysis of particle number fluctuations in the mixed phase of a first-order phase transition
Molecular dynamics simulations are performed for a finite non-relativistic
system of particles with Lennard-Jones potential. We study the effect of
liquid-gas mixed phase on particle number fluctuations in coordinate subspace.
A metastable region of the mixed phase, the so-called nucleation region, is
analyzed in terms of a non-interacting cluster model. Large fluctuations due to
spinodal decomposition are observed. They arise due to the interplay between
the size of the acceptance region and that of the liquid phase. These effects
are studied with a simple geometric model. The model results for the scaled
variance of particle number distribution are compared with those obtained from
the direct molecular dynamic simulations.Comment: 13 pages, 9 figure
Psychomotor Training of the Military Sappers as a Means of Reducing Personal Fears and Anxiety
The purpose of this study is to reveal the features of psychomotor training of a sapper, the development of the necessary sensory-intuitive skills to regulate their actions and deeds while performing tasks in the minefield. Material and methods. Three series of psychological experiments were conducted. The importance of psychomotor training in the context of reducing the level of anxiety and personal fears of sappers was revealed. The research was integrated into the process of training in the discipline “Blasting”. The study did not change the structure of the discipline, as it was only related to the content. The collected and analyzed data were used for the quantitative method. Results. It was determined that the most talented servicemen, with well-developed coordination of movements, mental stability, ability to regulate personal fears, make quick decisions, work alone for a long time, stay calm in tense situations, should be involved in the sappers’ activities. Conclusions. Our psychological training “Minefield” promotes the development of professionally necessary qualities among military sappers, provides the development of psychomotor and sensory-intuitive skills to regulate movements and actions during combat missions. Improves constructive attitudes in the unit of sappers, friendliness, reflexive listening, kindness, leadership and patience.</p