Original Welcome:
This event is dedicated to assembling experts on the fields of plasma and particle physics, in particular on laser induced fusion and particle production in intense fields. These research areas are promising for future development, they connect to the use of large scale international facilities, like CERN and ELI.
Main Topics:
On May 19-th Johann Rafelski has his birthday, presenting an additional occasion to review the above research topics in which he was making contributions. Jan was a Fulbright Fellow at the Budapest Wigner Research Centre for Physics during Summers in 2019-2021.
Keynote speakers
Invited Speakers
International Organizing Committee
Local Organizing Committee (Wigner RCP)
Important Deadlines
Strong interaction related talks
Above the chiral restoration crossover at T ~ 150 MeV the QCD effective action is approximately chiral spin symmetric. It is a symmetry of the color charge in QCD as well as of the chromoelectric interaction. This symmetry is larger than the chiral symmetry of Dirac Lagrangian. This symmetry implies that degrees of freedom are chirally symmetric quarks connected by electric strings into color singlet hadron-like objects. This regime is referred to as stringy fluid. At T ~500 MeV this symmetry disappears and a very smooth transition to partonic degrees of freedom (QGP) is observed. The chiral spin symmetric regime continues as a band across the QCD phase diagram and terminates on the chemical potential axis.
Investigation of the femtoscopic correlation functions in heavy ion collisions is an important tool to access the space-time structure of the hadron production of the sQGP. The description of the measured correlation functions is often assumed to be Gaussian or exponential, but a detailed analysis reveals that the statistically correct assumption is a generalized Gaussian, the symmetric alpha-stable Lévy distribution. One of the resulting source parameters, the Lévy stability parameter $\alpha$, describing the shape of the source, may be related to anomalous diffusion in the final state. In this talk we present measurements of two-particle, Bose-Einstein correlation functions in $\sqrt{s_{_{\mathrm{NN}}}} =$ 5.02 TeV PbPb collisions at CMS. We investigate the centrality and transverse mass dependence of the parameters of the correlation functions: the strength or the intercept parameter $\lambda$, the HBT scale parameter $R$ and the stability parameter $\alpha$.
Strong interaction related talks
Finite baryon density induces a direct mixing between vector
and axial-vector states, which yields multiple bumps and peaks around the vacuum masses of the rho, omega and phi resonances in the spectral function. The modification become significantly pronounced when the mass difference between the parity partners decreases at high density. We propose that the emergent enhancement in the dilepton production rates serves as an excellent signature of the partially-restored chiral symmetry to be verified in heavy-ion collisions.
The impact of mesonic fluctuations on the restoration of the $U_A(1)$ anomaly is investigated non-perturbatively for three flavors at finite temperature in an effective model setting. Using the functional renormalization group, the dressed, fully field dependent Kobayashi--Maskawa--'t Hooft (KMT) anomaly coupling is computed. It is found that mesonic fluctuations strengthen this signature of the $U_A(1)$ breaking as the temperature increases. On the other hand, when instanton effects are included by parametrizing the explicit temperature dependence of the bare anomaly parameter in consistency with the semi-classical result for the tunneling amplitude, a natural tendency appears diminishing the anomaly at high temperatures. As a result of the two competing effects, the dressed KMT coupling shows a well defined intermediate strengthening behavior around the chiral (pseudo)transition temperature before the axial anomaly gets fully suppressed at high temperature. As a consequence, we conclude that below $T \sim 200 \MeV$ the $U_A(1)$ anomaly is unlikely to be effectively restored. Robustness of the conclusions against different assumptions for the temperature dependence of the bare anomaly coefficient is investigated in detail.
Contrary to the field theoretical calculations in the thermodynamic limit where the volume is assumed to be infinitely large, the heavy-ion collisions always carry the effects of the finite size. For a sufficiently small system, the volume is expected to affect the thermodynamical quantities and the phase diagram of the strongly interacting matter. To study these effects one can take into account the finite spatial extent of the system within the framework of an effective model, too, via the restriction of the momentum integrals using discretization or in a simplified case using a low momentum cutoff. It is found in several models that there is a remarkable change in the thermodynamics and the phase transition, especially in the location of the critical endpoint and the tricritical point in the chiral limit. As the linear size reaches a few fermis the first-order phase transition at high chemical potential and therefore the CEP disappears.
Recent observation data of pulsar masses led us to estimate nuclear parameters, however. we introduced the maximal-mass compact star scenario and took into account data satisfying these criteria. We tested our method, applying the parity doublet model in the mean-field approximation at the finite chemical potential at zero temperature to investigate the recent observation data of pulsar masses. We assumed that these pulsars are maximal mass neutron stars, due to this reason we can apply the core approximation can be applied. The free parameters of this model are fitted based on the nuclear saturation data, except for the Landau mass and the compressibility. We used the observation data to determine the optimal Landau mass, and used the value to determine the nuclear compressibility respectively.
Particlization and hadronization of fields.
Hadronization is a non-perturbative process, which theoretical description can not be deduced
from first principles. Modeling hadron formation, requires several assumptions and various
phenomenological approaches. Utilizing state-of-the-art Computer Vision and Deep Learning
algorithms, it is eventually possible to train neural networks to learn non-linear and non-
perturbative features of the physical processes.
Here, I would like to present the results of two ResNet networks, by investigating global and
kinematical quantities, indeed jet- and event-shape variables. The widely used Lund string
fragmentation model is applied as a baseline in √s=7 TeV proton-proton collisions to predict the
most relevant observables at further LHC energies. Non-liear QCD scaling properties were also
identified and validated by experimental data.
[1] G. Bíró, B. Tankó-Bartalis, G.G. Barnaföldi; arXiv:2111.15655
Machine Learning (ML) techniques have been employed for the high energy physics (HEP) community since the early 80s to deal with a broad spectrum of problems. This work explores the prospects of using Deep Learning techniques to estimate elliptic flow (v2) in heavy-ion collisions at the RHIC and LHC energies. A novel method is developed to process the input observables from track-level information. The proposed DNN model is trained with Pb-Pb collisions at sNN−−−√=5.02 TeV minimum bias events simulated with AMPT model. The predictions from the ML technique are compared to both simulation and experiment. The Deep Learning model seems to preserve the centrality and energy dependence of v2 for the LHC and RHIC energies. The DNN model is also quite successful in predicting the pT dependence of v2. When subjected to event simulation with additional noise, the proposed DNN model still keeps the robustness and prediction accuracy intact up to a reasonable extent.
Measurements of jet profiles in high-energy collisions are sensitive probes of
QCD parton splitting and showering. Precise understanding of the jet struc-
tures are essential for setting the baseline not only for nuclear modification of
jets in heavy-ion collisions, but also for possible semi-soft cold QCD effects such
as multi-parton interactions (MPI) that may modify jets in high-multiplicity
proton-proton collisions. We analyzed the jet radial profiles in simulations,
and defined a multiplicity-dependent characteristic jet size that is universal
in a broad range of model classes regardless of parton distributions and the
presence or absence of MPI and color-reconnection [1]. In this contribution
we demonstrate that the radial jet profiles in proton-proton collisions exhibit
scaling properties with charged-hadron event multiplicity in the full experimen-
tally accessible transverse-momentum range. Based on this we propose that
the scaling behavior stems from fundamental statistical properties of jet frag-
mentation [2]. We also study the multiplicity distributions of events with hard
jets and show that the charged-hadron multiplicity distributions scale with jet
momentum. This suggests that the Koba–Nielsen–Olesen (KNO) scaling holds
within a jet. The in-jet scaling is fulfilled without MPI, but breaks down in case
of its presence without color reconnection. Our findings imply that KNO scal-
ing is violated by parton shower or MPI in higher-energy collisions [3]. Besides
these results, newest findings on the flavor-dependence of scaling properties will
also be presented.
References
[1] Z. Varga, R. V ́ertesi and G. G ́abor Barnaf ̈oldi, Adv. High Energy Phys.
2019, 6731362 (2019) [arXiv:1805.03101 [hep-ph]].
[2] A. G ́emes, R. V ́ertesi, G. Papp and G. G. Barnaf ̈oldi, in: Gribov-90 Memo-
rial Volume: Algebraic Methods in QFT (2021) [arXiv:2008.08500 [hep-ph]].
[3] R. V ́ertesi, A. G ́emes and G. G. Barnaf ̈oldi, Phys. Rev. D 103, no.5, L051503
(2021) [arXiv:2012.01132 [hep-ph]]
The production of heavy-flavor hadrons is usually described using the factorization hypothesis, in
which the production cross section is expressed as convolutions of three independent factors: the
parton distribution functions (PDF) of the colliding hadrons, the production cross-sections of the
heavy-quarks in the hard partonic process, and the fragmentation functions of the heavy-quarks into
the given heavy-flavor hadron species. Fragmentation has been widely regarded as being universal,
that is, independent of the collision system.
Charmed-baryon to meson ratios recently measured by ALICE and CMS at the LHC, however,
show a low-momentum enhancement over model predictions based on e+ -- e- collisions,
suggesting that universality is not fulfilled [1,2]. Furthermore, recent measurements showed that
this enhancement depends on the final-state multiplicity [3]. Several scenarios, based on string
formation beyond leading order, an augmented set of charm baryon states, or quark coalescence in
p--p collisions provide qualitative descriptions to these findings.
In this contribution we investigate the enhanced production of charmed baryons relative to charmed
mesons in proton--proton collisions at LHC energies utilizing PYTHIA 8 simulations with enhanced
color-reconnection. We proposed methods based on the comparative use of several event-activity
classifiers to identify the source of the charmed-baryon enhancement. We concluded that in the
investigated models the excess Λc production is primarily linked to the underlying event activity
and not to the production of jets. [4] We provide predictions for ratios of further charmed-baryon to
baryon and meson states to understand the role of strangeness and charm in the enhancement. The
proposed event-activity-differential observables, when utilized on data from the upcoming LHC
Run 3, will provide high selectivity and valuable input for model development.
[1] CMS Coll., Phys. Lett. B 803 (2020) 135328, arXiv:1906.03322.
[2] ALICE Coll., Physicial Review Letters 127, 202301 (2021), arXiv:2011.06078.
[3] ALICE Coll., CERN-EP-2021-245, arXiv:2111.11948.
[4] Z. V., R. V., arXiv:2111.00060, Submitted to J.Phys.G.
Particlization and hadronization of fields.
Heavy Ion Collisions (HIC) provided the possibility of researching the phase transitions from hadronic matter to the predicted Quark-Gluon Plasma (QGP) phase based on partonic degrees of freedom. Conditions at HIC – nuclear densities much higher than nuclear density and/or temperatures above 150 MeV – suggest such a form of matter both dominant just after the Big Bang as in the cores of neutron stars. Data from HIC confirm that these conditions, both temperatures, and densities have been reached. Contrary to early concepts, based on QCD asymptotic freedom property, the partonic matter has no properties of an almost ideal state of quarks and gluons. The behavior appears of a fluid with very low kinematic viscosity with strong hydrodynamic flows. This
means an almost perfect fluid state, which means quite powerful interactions between constituents. The success of hydrodynamic description in the heavy-ion collisions suggests
the appearance of very fast local thermalization at 1 fm/c. The demand for local (at least) thermalization has been a cornerstone of the hydrodynamical approach. Recent data of hydrodynamical behavior in small systems, e.g. p-p or p-Pb data put a question mark on the logic chain: hydro=thermalization, thermalization needs time, time
accessible in large systems only, so hydrodynamic behavior confirms the appearance of the QGP state. It was shown, however, that even far from equilibrium is hydrodynamics applicable.
Dissipative processes are needed here to get this result. Dissipative processes are necessary here to get this result. The effect of dissipation is more pronounced at the very early stages of heavy-ion collisions This means also that the hadrodynamic behavior does not confirm the QGP state. So there is still an open question about the signature of the QGP. The lecture aims to describe mechanisms that change the composition of the fluid, i.e. particle production and/or chemical reactions. This will be exemplified with the strangeness behavior as it has a special role as the QGP signature. Strangeness production will be connected with entropy growth. Then the viscosity due to the strangeness production and its influence on the state of the system would be estimated. Cooling beyond the flow of matter will be taken into account here
The ubiquitous presence of quasi-power law functions
in multiparticle production processes are discussed
from the perspective of nonextensive Tsallis distributions.
Special emphasis is placed on the conjecture that this
reflects the presence in the produced hadronic systems
of some intrinsic fluctuations.
In particular we analyze a connection between energy
and multiplicity distributions in a statistical framework.
We show that energy conservation constraints may lead
to the quasi-power law distributions for energy with an exponent
depending on multiplicity distribution. We demonstrate that energy
distributions are connected with multiplicity distributions
by their generating functions.
We also discuss the relaxation time approximation (RTA)
which is a well known method of describing the time evolution
of a statistical ensemble by linking distributions of the variables
of interest at different stages of their temporal evolution.
We show that if all the distributions occurring in the RTA have
the same functional form of a quasi-power Tsallis distribution
the time evolution of which depends on the time evolution
of its control parameter, nonextensivity q(t), then it is more
convenient to consider only the time evolution of this control
parameter.
We have analyzed the transverse momentum spectra of charged particles in high multiplicity pp collisions at LHC energies 5.02 and 13 TeV using the Color String Percolation Model (CSPM). For heavy ions, Pb-Pb at 2.76 and 5.02 TeV along with Xe-Xe at 5.44 TeV have been analyzed. The initial temperature is extracted both in low and high multiplicity events in pp collisions. For heavy-ion collisions, the temperature is obtained as a function of centrality. Universal scaling in the temperature from pp and A − A collisions is obtained when multiplicity is scaled by the transverse interaction area. For the higher multiplicity events in pp collisions at 5.02 and 13 TeV, the initial temperature is above the universal hadronization temperature and is consistent with the creation of deconfined matter. From the measured
energy density ε and the temperature, the dimensionless quantity ε/T4 is obtained. Our results agree with the Lattice Quantum Chromo Dynamics simulations (LQCD) up to ∼210 MeV and beyond that there is a sharp increase in ε/T4, reaching the ideal gas of quarks and gluons value of ε/T4 = 16 at temperature ∼ 230 MeV. It has been argued that there exists a three-phase structure of matter in QCD: hadronic matter, a plasma of deconfined massive quarks and a plasma of massless quarks and gluons with full-color deconfinement and chiral symmetry restoration. Our results suggest that chiral symmetry restoration occurs at a temperature
∼210 MeV.
We present reports on progress in the solution of the mass dynamical gen-
eration problem in particle physics at the fundamental level of the strong
interactions. It is based on new significant insights into the true dynamical
and gauge structures of the QCD ground state. The conclusive proof has
been given that the structure of the QCD ground state is much more com-
posite than it is determined by its Lagrangian exact gauge symmetry. All
of these made possible to formulate the novel non-perturbative analytical
approach to QCD, reflecting these complexities.
I give a general analysis of how to represent Wilson loops in the
Hamiltonian formulation. This requires enlarging the physical
space of states to include the external charge on the Wilson loops. The character representation is used in an essential manner. As a byproduct, it demonstrates how to continue the Polyakov loop, which appears peculiar to imaginary time, to real time.
Physics of strong fields, including pair creation.
Strong fields create strong acceleration and thus a strong radiation reaction (RR) force. We demonstrate within the Eliezer-Ford-O'Connell (EFO) RR model for many externally applied field configurations D,H a Lorentz-invariant upper bound to the acceleration of a particle. A limit to the strength of acceleration implies a limit to the strength of EM force fields E,B reminiscent of the limiting field strength present within the Born-Infeld model of electromagnetism. We show that the commonly used Landau-Lifshitz (LL) RR-model a) arises from a perturbative expansion of EFO and b) does not limit acceleration. In the ongoing research program we are seeking to extend the RR force involving in a dynamical way the interaction of accelerated charged particles with the (quantum) vacuum, using the method of path warping which we developed to describe RR in material background. Path-warping relaxes the orthogonality constraint on the covariant equation of motion resolving self-acceleration conflicts introduced by the Schott RR term. We hope that within the path warping approach a variational RR principle appears which has escaped prior discovery. A related lingering question is if strong RR effects are already inherent to QED. We address this question by comparing particle scattering cross sections obtained within RR model with the know (scalar) QED cross sections. For further reading see:
[1] Radiation reaction and limiting acceleration; 2112.04444 Will Price, Martin Formanek, JR
https://doi.org/10.1103/PhysRevD.105.016024
[2] Radiation reaction friction: Resistive material medium; 2004.09634 Martin Formanek, Andrew
Steinmetz, JR, https://doi.org/10.1103/PhysRevD.102.056015
There is a renewed interest in extending relativistic description of plasma response in external electromagnetic fields from Vlasov equation to a form including Boltzmann collision term [1–4]. In this work we incorporate the relaxation rate approximation of collisions [2] in a manifestly covariant way assuring explicitly current and energy-momentum conservation for two-component electron-positron plasma. We demonstrate that the resulting equation for the perturbation of the Fermi-Dirac equilibrium distribution function can be solved analytically to the linear order in external fields [5]. The ultra-relativistic and non-relativistic limits of the resulting covariant, gauge invariant, and current-conserving polarization tensor can be taken. We evaluate the plasma susceptibility and conductivity in the ultra-relativistic case and study their dependence on the collision rate. Finally, we explore the dispersion relations for the longitudinal and transverse poles of the propagator.
References
[1] P. L. Bhatnagar, E. P. Gross and M. Krook, Phys. Rev. 94, 511 (1954).
[2] J. L. Anderson, H. R. Witting, Physica 74, 466 (1974).
[3] D. Satow, Phys. Rev. D 90, 034018 (2014).
[4] G. S. Rocha, G. S. Denicol and J. Noronha, Phys. Rev. Lett. 127, no.4, 042301 (2021).
[5] M. Formanek, C. Grayson, J. Rafelski and B. M ̈uller, Annals Phys. 434, 168605 (2021
We investigate the electromagnetic response of quark-gluon plasma starting from the Boltzmann
equation in the limit of linear response. We model the quark-gluon plasma as an infinite medium
of ultra-relativistic quarks and anti-quarks which collide with a momentum averaged damping rate
in the BGK approximation. This medium is then perturbed electromagnetically by colliding heavy
ions and the resulting electro-magnetic field is evaluated and its observable effects discussed.
We study the QED effective action in strong electric fields. Employing the Weisskopf (1936) and
Nikishov (1969) summation methods, novel analytical properties of the QED strong field effective
action are discovered, inaccessible to Schwinger proper time method. Using these rediscovered
tools we incorporate anomalous magnetic moment as a correction to the Euler-Heisenberg, and
Sauter potential step actions. The resulting nonperturbative phenomena include periodicity in the
spin g-factor with a cusp at g=2. We demonstrate how these effects impact particle production
in both quasi-constant and sharply localized fields, at strengths achieved in relativistic heavy ion
collisions and relevant to magnetars
References
Emergence of periodic effective action in electric backgrounds: The case of arbitrary magnetic
moment. S. Evans, J. Rafelski. In preparation.
J. Rafelski, L. Labun, S. Evans, A cusp in QED at g=2. In preparation, see also arXiv:1205.1835
Physics of strong fields, including pair creation.
The high-intensity light pulses used in mutiphoton experiments come from amplifiers,
and these pulses contain quite strong (unwanted) ‘pre-pulses’, or ‘pedestals’. The main source of
the pedestal is said to be the amplified spontaneous emission (ASE) of the amplifying medium.
Since the photon statistics of the ASE is differe nt from that of the main pulse, the study of
multiphoton processes taking place in a pedestal may be interesting, both in theory and in
experiments. Recently we have worked out a general quantum optical theory of multiphoton
processes [1, 2], on the basis of which, we shall deal with the possible role of photon statistics in
electron excitation, scattering and high-harmonic generation in the field of a ‘pedestal’.
References.
[1] Varró S, Quantum optical aspects of high-harmonic generation. Photonics 8, 269 (2021)
[https://doi.org/10.3390/photonics8070269 ].
[2] Varró S, Coherent and incoherent superposition of transition matrix elements of the squeezing
operator. Journal of Physics Conf. Ser. (2022). E-print: arXiv: 2112.08430 [quant-ph]
We investigate the usage of a Schlieren imaging setup to measure the geometrical dimensions of a plasma channel in atomic vapor. Near resonant probe light is used to image the plasma channel in a tenuous vapor and machine learning techniques are tested for extracting quantitative information
from the images. By building a database of simulated signals with a range of plasma parameters for training Deep Neural Networks, we demonstrate that they can extract from the Schlieren images reliably and with high accuracy the location, the radius and the maximum ionization fraction of the plasma channel as well as the width of the transition region between the core of the plasma channel and the unionized vapor. We test several different neural network architectures with supervised learning and show that the parameter estimations supplied by the networks are resilient with respect to slight changes of the experimental parameters that may occur in the course of a measurement.
We present a new family of exact solutions of dissipative fireball hydrodynamics for arbitrary bulk and shear viscosities. The main property of these solutions is a spherically symmetric, Hubble flow field. The motivation of this paper is mostly academic: we apply non-relativistic kinematics for simplicity and clarity. In this limiting case, the theory is particularly clear: the non-relativistic Navier–Stokes equations describe the dissipation in a well-understood manner. From the asymptotic analysis of our new exact solutions of dissipative fireball hydrodynamics, we can draw a surprising conclusion: this new class of exact solutions of non-relativistic dissipative hydrodynamics is asymptotically perfect. We present a new family of exact solutions of dissipative fireball hydrodynamics for arbitrary bulk and shear viscosities. The main property of these solutions is a spherically symmetric, Hubble flow field. The motivation of this paper is mostly academic: we apply non-relativistic kinematics for simplicity and clarity. In this limiting case, the theory is particularly clear: the non-relativistic Navier–Stokes equations describe the dissipation in a well-understood manner. From the asymptotic analysis of our new exact solutions of dissipative fireball hydrodynamics, we can draw a surprising conclusion: this new class of exact solutions of non-relativistic dissipative hydrodynamics is asymptotically perfect.
In addition to the already published results we present recent generalizations to spheroidal and triaxial, rotating expansions.
Published as:
Kasza, G.; Csernai, L.P.; Csörgő, T. New, Spherical Solutions of Non-Relativistic, Dissipative Hydrodynamics. Entropy 2022, 24, 514. https://doi.org/10.3390/e24040514
The European XFEL produces up to 20 GeV electron bunches with a repetition of up to 27 kHz to ultimately provide a large range of coherent X-rays to users with individual pulse energies on the order of 1 mJ. We discuss the development of a new experimental program, Superradiant THz radiation at the European XFEL (STERN), to produce large THz fields by passing the electron beam through Cherenkov waveguides including dielectric, corrugated, bimetallic waveguides, or crystal fibers. We discuss recent simulation and experimental results based on 3D printing these complex structures. Finally we discuss their application in our proposed novel laser-based accelerators and diagnostics, and also to provide a pump-probe platform for users at the XFEL.
Surface plasmon phenomena.
Sorface plasmon polaritons (SPP) and their localized versions (LSPP) have numerous special properties, opening the way to a high number of applications. One group of these applications is connected with the generation of plasmons in extremely high EM fields, being the topics of the present talk. High intensity femtosecond laser pulses have been used for the plasmonic excitation. The created extremely high electromagnetic field intensity in the plasmonic hot spots has been explored. to study electronic and nuclear processes in some resonant nanoparticle doped transparent materials or on metallic (gold) surfaces . Some experimental results and their theoretical explanations are briefly presented. Time-of-flight multiplasmon electron emission analysis, scanning tunneling microscopy, Raman sectroscopy and laser induced breakdown spectroscopy methods have been used to get the experimental data The results of some of our experimental results and theoretical findings are briefly presented.
In this talk, I will give an introduction to the laser systems, laser-driven attosecond and particle sources and some state-of-the-art user endstations of the ELI-ALPS facility located in Szeged, Hungary.
The recent development of quantum technology may allow us to use quantum computers to efficiently simulate quantum dynamics in the near future. In this talk, I will discuss how quantum simulation may help us to deepen our understanding of some transport phenomena inside plasma by showing two examples. The first example is the 1+1D U(1) gauge theory, also known as the Schwinger model, evolving inside a hot plasma made up of scalar fields. I will show both the string breaking and reconnection processes, the latter of which is similar to quarkonium regeneration inside the quark-gluon plasma (QGP), an important idea brought up by Thews, Schroedter and Rafelski to explain J/psi production enhancement. The second example is jet quenching in the QGP. I will show how to use light-front QCD Hamiltonian and quantum simulation to study the Landau-Pomeranchuk-Migdal effect for processes with three or more splittings, which are beyond the scope of the current methods.
Diverse ideas from all areas of theoretical physics.
In modern continuum mechanics there are several mathematical methods to deduce the consequences of the entropy inequality: establis constitutive functions, constitutive relations and evolution equations. These methods are challenged by gradient dependent constitutive state spaces. One of the most powerfull techniques is Liu procedure, a method to solve conditional inequalities. Then one can get thermodynamic compatible gradient expansions including both dissipative and nondissipative parts of the evolution equations. In the presentation I show that the second law restricts the form of evolution equations and with correct spacetime representation one can arrive to gradient expansions that are surprisingly physical: quantum theory and also gravity appear as a natural consequences of the second law [1,2].
[1] Vá, P. ; Kovács, R.
Variational principles and nonequilibrium thermodynamics
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A - MATHEMATICAL PHYSICAL & ENGINEERING SCIENCES 378 : 2170 Paper: 20190178 , 16 p. (2020)
[2] Ván, P.; Abe, S.
Emergence of extended Newtonian gravity from thermodynamics
PHYSICA A - STATISTICAL MECHANICS AND ITS APPLICATIONS 588 Paper: 126505 , 7 p. (2022)
We consider the evolution equations for the bulk viscous pressure, diffusion current and shear
tensor derived within the second order relativistic dissipative hydrodynamics from kinetic theory.
By matching the higher order moments directly to the dissipative quantities, all terms which are
of second order in the Knudsen number Kn vanish, leaving only terms of order O(Re−1 Kn) and
O(Re−2) in the relaxation equations, where Re−1 is the inverse Reynolds number. We therefore
refer to this scheme as the Inverse Reynolds Dominance (IReD) approach. The remaining (non-
vanishing) transport coefficients can be obtained exclusively in terms of the inverse of the collision
matrix. This procedure fixes unambiguously the relaxation times of the dissipative quantities, which
are no longer related to the eigenvalues of the inverse of the collision matrix. In particular, we find
that the relaxation times corresponding to higher order moments grow as the order of moments
increases, thereby contradicting the separation of scales paradigm. The formal (up to second order)
equivalence with the standard DNMR approach is proven and the connection between the IReD
transport coefficients and the usual DNMR ones is established.
In most of the engineering problems, the classical constitutive laws such as Fourier and Navier-Stokes equations are applicable. However, there are certain cases when these models require the generalization of the constitutive equations [1]. Such deviation can be observed also in case of rarefied gases. The deviation occurs due to the so-called ballistic propagation effects [2].
In this talk, different interpretations are shown for ballistic propagation; one of them is related to a specific heat conduction experiment on NaF samples performed by McNelly et al. The other one is related to an experiment on rarefied gases conducted by Rhodes. For the NaF experiment, the so-called ballistic-conductive model is tested with success and its theoretical background is implemented for the coupled system of Navier-Stokes-Fourier (NSF) in order to obtain a similar generalization.
The resulting generalization of NSF equations is tested on Rhodesâ experiment; furthermore, its compatibility with kinetic theory is investigated [3]. It turned out that the exact same generalization of entropy applied for heat conduction, also applicable for the NSF theory and called as âballistic generalizationâ that highlights some thermodynamic equivalence of different conducting medium where ballistic propagation occurs.
References
[1] S. Both et al.: Deviation from Fourier law at room temperature heterogeneous materials. Journal of Non-Equilibrium Thermodynamics, 41(1), 2016.
[2] R. KovĂĄcs: On the rarefied gas experiments. Entropy 21(7), Paper: 718, 2019.
[3] R. KovĂĄcs, P. Rogolino, D. Jou: When theories and experiments meet: Rarefied gases as a benchmark of non-equilibrium thermodynamic models, International Journal of Engineering Science, 169, Paper: 103574, 2021.
We find an argument related to the existence of a Z_2-symmetry for the renormalization group flow derived from the bare Yang–Mills Lagrangian, and show that the cancellation of the vacuum energy may arise motivated both from the renormalization group flow solutions and the effective Yang–Mills action. In the framework of the effective Savvidy’s action, two Mirror minima are allowed, with exactly equal and hold opposite sign energy densities. At the cosmological level, we explore the stability of the electric and magnetic attractor solutions, both within and beyond the perturbation theory, and find that thanks to these latter the cancellation between the electric and the magnetic vacua components is achieved at macroscopic space and time separations. This implies the disappearance of the conformal anomaly in the classical limit of an effective Yang–Mills theory. In this picture, the tunnelling probability from the Mirror vacua to the other vacua is exponentially suppressed in the quantum non-thermal state – similarly to what happens for electroweak instantonic tunnelling solutions. Specifically, we show that, in a dynamical
Friedmann–Lemaître–Robertson–Walker (FLRW) cosmological background, the Nielsen–Olsen argument – on the instability of uniform chromo-electric and chromo-magnetic Mirror vacua – is subtly violated. The chromo-magnetic and chromo-electric uniform vacua are unstable only at asymptotic times, but at those times the attractor to a zero energy density is already reached. The two vacua can safely decay into one anisotropic vacuum that has zero energy-density inside the Fermi confinement volume scale. We also discover a new surprising pattern of solitonic and anti-solitonic space-like solutions, which are sourced by the Yang–Mills dynamics coupled to the Einstein’s equations in FLRW. We dub such non-perturbative configurations, which are directly related to dynamical cancellation mechanism of the vacuum energy, as chronons, or χ -solutions. The time-ordered classical solution that we found is a time crystal, i.e. a periodic classical solution spontaneously breaking time invariance down to a discrete time shift symmetry. The spontaneous symmetry breaking of T-invariance from the localization of chronons is associated to the appearance of Nambu-Goldstone bosons, as time-like moduli excitations over the classical background
Proton therapy is a novel treatment against cancer, thanks to its advantageous deep dose distribution
containing the so-called Bragg-peak, just before the stopping position of the protons. To focus this peak
into the tumor volume is a big challenge, as it requires the determination of the deep dose distribution
for every beam during dose planning. This incoming information of the deep dose curve calculation is
the distribution of the relative stopping power (RSP). The more accurate the RSP map the smaller safety
margin is enough to avoid the inadequate dose in the tumor. The goal of proton imaging is to provide an
accurate and reliable tool to take the RSP map, which measures the independent and precise energy
and direction of protons. One of the most promising solutions is a range counter concept build of silicon
pixel detectors. This type of detector is developed by the Bergen pCT collaboration, which is determined
to reduce the imaging duration into a range that is acceptable for clinical use. In this presentation I will
highlight the problem of three-dimensional reconstruction of the RSP map from independent proton
histories.
Nuclear fusion enhancement ideas by strong laser fields.
Motivated by the nonlinear Schrödinger equation of Kostin we propose a novel method to
extract kinetic energy from an ensemble of quantum particles. This task is achieved by applying
external time-dependent forces governed by the phase of the wave function. In particular, we
demonstrate that a Gaussian wave packet climbing an appropriately designed inverted
harmonic oscillator potential creates a momentum eigenstate arbitrarily close to one with a
vanishing eigenvalue. We also suggest an experiment with cold atoms which can be realized
with state-of-the-art technology.
This work was performed in collaboration with H. Losert, F. Ullinger, M. Zimmermann, M.A.
Efremov, and E.M. Rasel.
he talk is connected to the Hungarian NAPLIFE (Nanoplasmonic Laser Inertial Fusion Experiment) collaboration and will discuss various aspects of the fusion target material development. Design considerations for a model target material - namely a nanocomposite consisting of nanoparticles doped into a polymer matrix - and its realization will be presented, along with results related to nanoparticle synthesis, surface chemistry, nanocomposite preparation, and characterization with a wide range of instrumentation (electron microscopy, optical and Raman spectroscopy). Methods to tune the plasmonic absorption peak of the nanocomposite and control the density of the doped nanomaterials in the polymer matrix will be discussed in detail.
Laser induced Inertial Confinement Fusion has some
difficulties. In the NAPLIFE project our aim is to circumvent
these by new ideas from ultra-relativistic heavy ion reactions
and nanotechnology. We aim for time-like detonation to avoid
instabilities and slow spreading of the burning front and
regulate the light absorption in the target by implanted
nano-antennas.
Nuclear fusion enhancement ideas by strong laser fields.
Raman spectroscopy is widely used to characterize different materials through characteristic vibrations of their constituents. It is highly sensitive to changes in bonding configuration, crystalline structure, isotope content, or even internal stress. We report on Raman spectroscopic studies of structural transformations in urethane dimethacrylate/triethylene glycol dimethacrylate copolymer nanocomposite doped with gold nanorods upon irradiation with a high-energy femtosecond laser pulse. The plasmon resonance of the nanorods has been tuned to the 800 nm wavelength of the laser, and the plasmonic enhancement of the electromagnetic field in their vicinity resulted in surplus crosslinking and other alterations in the polymeric structure.
In the presence of an external electric field, electron-hole
pairs are amply created near the Dirac points in graphene. Due to the ef-
fective coupling constant being more than unity (2.2 for pristine graphene)
perturbative techniques are futile in describing the phenomenon. We
present a non-perturbative kinetic equation approach to describe the
creation of an electron-hole plasma in a strong external field by a set of
integro-differential equations for the distribution function of the charge
carriers. In this presentation, an approximate solution to these kinetic
equations will be discussed. The low-density approximation and the in-
troduction of effective mass provide simple methods that are effective
for a wide range of external field models. Comparing with the exact so-
lution, the domain is identified where the approximations are effectively
applicable.
We use the linear response theory to describe the inter-nuclear potential in dense early Universe
e ̄e-pair plasma. We account for nuclear motion perturbing plasma as a function of time. Prior
efforts are improved by inclusion of moving screening charge scattering in the dense plasma medium
and quantitative evaluation of the governing collision damping rate. We asses the influence of these
new dynamical screening effects on the thermonuclear BBN reaction rates
Diverse ideas from all areas of theoretical physics.
The introduction of nonadditive entropies enables a convenient generalization of Boltzmann-Gibbs statistical mechanics, currently referred to as nonextensive statistical mechanics. Its foundations and illustrative applications to high energy physics, plasmas and scale-free networks will be briefly presented.
Updated Bibliography is available at http://tsallis.cat.cbpf.br/biblio.htm , including Tsallis, “Entropy”, Encyclopedia 2, 264 (2022), and Umarov and Tsallis “Mathematical Foundations of Nonextensive Statistical Mechanics” (World Scientific, Singapore, 2022).
When we understand a subject, we feel that we put the earlier messy state of the thoughts in order. Since messiness is associated with high entropy, learning, in some sense, should mean entropy reduction, and a completely understood subject should be represented with the least entropy. To give these ideas a formal description, we need to speak about the different representations of a phenomenon, and associate a representation with a given level of understanding. Then we can define a representation entropy, and prove its minimality in the best representation of the knowledge. In this talk this program is demonstrated for a simple pattern recognition task, to tell apart a few bit long 'cat images' from the 'non-cat images'.