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Using the external field method, {\it i.e.\/} evaluating the effective action $V_{\mathrm{eff}}$ for an arbitrarily strong constant and homogeneous field, we explore nonperturbative properties of QED allowing arbitrary gyromagnetic ratio $g$. We find a cusp at $g = 2$ in: a) The QED $b_0$-renormalization group coefficient, and in the infinite wavelength limit in b) a subclass containing the pseudoscalar ${\cal P}^{2n}= (\vec E\cdot\vec B)^{2n} $ of light-light scattering coefficients. Properties of $b_0$ imply for certain domains of $g$ asymptotic freedom in an Abelian theory., 12 pages, 3 figures. This paper builds on the work in arXiv:1205.1835, motivated by recent advances in the Dirac-Pauli-based QED effective action, and with extended author list

This is a brief review of our work describing the hadronization process of a QGP fireball formed in relativistic heavy-ion collisions. We introduce the SHARE method of analysis of hadron multiplicities. Using this tool we describe in consistent continuos manner the yield of all hadrons produced in the available range of reaction energies and centralities. The properties of the fireball final state can be understood by considering all primary hadronic particles. The dense hadron fireball created at SPS, RHIC, and LHC shows that the final state is differentiated solely by: i) volume changes; and ii) flavor (strangeness, charm) content. Conversely, emerging particles add up to create universal hadronization pressure $P = 80 \pm 3$ MeV/fm$^3$ for all considered collision systems. The relative strangeness to entropy content of a large fireball is found to be that of quark-gluon plasma degrees of freedom near the chemical QGP equilibrium. This 'Universal Hadronization' condition common to SPS, RHIC, and LHC agrees with the proposed reaction picture of a direct QGP fireball evaporation into free-streaming hadrons., 11 pages, many figures; Presented in Wroclaw at the February 2014 MB32-Symposium honoring Ludwik Turko

Before matter as we know it emerged, the universe was filled with the primordial state of hadronic matter called quark–gluon plasma. This hot soup of quarks and gluons is effectively an inescapable consequence of our current knowledge about the fundamental hadronic interactions: quantum chromodynamics. This book covers the ongoing search to verify the prediction experimentally and discusses the physical properties of this novel form of matter. It begins with an overview of the subject, followed by a discussion of experimental methods and results. The second half of the book covers hadronic matter in confined and deconfined form, and strangeness as a signature of the quark-gluon phase. It is ideal as an introduction for graduate students, as well as providing a valuable reference for researchers already working in this and related fields. This title, first published in 2002, has been reissued as an Open Access publication on Cambridge Core.

We investigate the electromagnetic response of a viscous quark-gluon plasma in the framework of the relativistic Boltzmann equation with current conserving collision term. Our formalism incorporates dissipative effects at all orders in linear response to the electromagnetic field while accounting for the full space- and time-dependence of the perturbing fields. As an example, we consider the collision of two nuclei in a stationary, homogeneous quark-gluon plasma. We show that for large collision energies the induced magnetic fields are governed by the response of quark-gluon plasma along the light-cone. In this limit we derive an analytic expression for the magnetic field along the beam axis between the receding nuclei and show that its strength varies only weakly with collision energy for $\sqrt{s_\mathrm{NN}} \ge 30\,$GeV., 13 pages, 7 figures

Three different types of measurement are described. In cases 1) and 2) the ends of the body emit signals that are observed, allowing: 1) spatial separation measurement with the signal synchronized in the rest-frame of the observer; and 2) spatial separation measurement with the signal synchronized in the rest-frame of a body. We find from 1) and 2) that the Lorentz contraction is associated with measurement in which the observer evaluates in her rest-frame at the same time the two ends of a body moving in direction of its velocity. In case 3) the spatial separation measurement of body ends under illumination with light emitted in the rest-frame of the observer is considered, showing that additional time delay associated with the light travel to the extended material object introduces a rotated view of the observed body.

Considerable effort is devoted to show how space and body differ in relativity. We consider the example of two rockets set in motion in synchronous way, connected by a fragile thread; rockets are allowed to move faster and faster: while spatial distance of rockets remains unchanged, the Lorentz-contracted thread breaks. We show that one can record the history of contraction effects just like one does with the time dilation effect measuring time using a clock; this allows us to design a body-contraction measuring device.

With the mass-energy \(m=E(v=0)/c^{2}\) relation, all pivotal properties of special relativity have been now derived and we consider the related status of SR tests. 1) There are direct tests exploring i) the speed of light in different context, ii) the time dilation, iii) the body contraction, and iv) mass-energy relation. 2) The Michelson-Morley experiment tests indirectly body-contraction and more generally the relativity principle and aether properties. 3) Another family of tests addresses the verification of the Lorentz coordinate transformation. 4) We describe the Doppler effect tests which test relativity per se. We close with a discussion of time and how it is different from space.

We investigate the strong acceleration properties of the radiation reaction force and identify a new and promising limiting acceleration feature in the Eliezer-Ford-O'Connell model; in the strong field regime, for many field configurations, we find an upper limit to acceleration resulting in a bound to the rate of radiation emission. If this model applies, strongly accelerated particles are losing energy at a much slower pace than predicted by the usual radiation reaction benchmark, the Landau-Lifshitz equation, which certainly cannot be used in this regime. We explore examples involving various "constant" electromagnetic field configurations and study particle motion in a light plane wave as well as in a material medium., 14 pages, 4 figures, 1 table

Spontaneous pair production for spin-$1/2$ and spin-$0$ particles is explored in a quantitative manner for a static $\tanh$-Sauter potential step (SS), evaluating the imaginary part of the effective action. We provide finite-valued per unit-surface results, including the exact sharp-edge Klein paradox (KP) limit, which is the upper bound to pair production. At the vacuum instability threshold the spin-$0$ particle production can surpass that for the spin-$1/2$ rate. Presenting the effect of two opposite sign Sauter potential steps creating a well we show that spin-$0$ pair production, contrary to the case of spin-$1/2$, requires a smoothly sloped wall., Comment: 10 pages, 6 figures

We investigate the response of a relativistic plasma to electromagnetic fields in the framework of the Boltzmann equation incorporating a collision term in the relaxation rate approximation selected in a form assuring current conservation. We obtain an explicit solution for the linearized perturbation of the Fermi-Dirac equilibrium distribution in terms of the average relaxation rate $\kappa$. We study the resulting covariant, gauge invariant, and current conserving form of the polarization tensor in the ultrarelativistic and non-relativistic limits. We evaluate the susceptibility in the ultrarelativistic limit and explore their dependence on $\kappa$. Finally, we study the dispersion relations for the longitudinal and transverse poles of the propagator. We show that for $\kappa> 2\omega_p$, where $\omega_p$ is the plasma frequency, the plasma wave modes are overdamped. In the opposite case, $\kappa \ll \omega_p$, the propagating plasma modes are weakly damped., Comment: 14 pages, 9 figures

We study the motion of a charged particle with magnetic moment in external electromagnetic fields utilizing covariant unification of Gilbertian and Amperian descriptions of particle magnetic dipole moment. Considering the case of a current loop, our approach is verified by comparing classical dynamics with the classical limit of relativistic quantum dynamics. We obtain motion of a charged particle in the presence of an external linearly polarized EM (laser) plane wave field incorporating the effect of spin dynamics. For specific laser-particle initial configurations, we determine that the Stern-Gerlach force can have a cumulative effect on the trajectory of charged particles., Comment: 11 pages PR-style, 4 figures

We explore a novel method of describing the radiation friction of particles traveling through a mechanically resistive medium. We introduce a particle motion induced matter warping along the path in a manner assuring that charged particle dynamics occurs subject to radiative energy loss described by the Larmor formula. We compare our description with the Landau-Lifshitz-like model for the radiation friction and show that the established model exhibits non-physical behavior. Our approach predicts in the presence of large mechanical friction an upper limit on radiative energy loss being equal to the energy loss due to the mechanical medium resistance. We demonstrate that mechanical friction due to strong interactions, for example of quarks in quark-gluon plasma, can induce significant soft photon radiation., Comment: 11 pages, 4 figures

Strangness production processes can balance natural strangeness decay in the early hadronic Universe. Comparing to the characteristic Hubble time $1/H$, the reaction rates for $\mu^\pm+\nu_{\mu}\rightarrow K^\pm$, $l^-+l^+\rightarrow\phi$, and $\pi+\pi\rightarrow K$ in sequence become slower than expansion rate at $T=33.9\,\mathrm{MeV}$, $T=25\,\mathrm{MeV}$ and $T=20\,\mathrm{MeV}$ respectively. This means that in the antibaryon annihilation epoch near to $T\simeq 40\,\mathrm{MeV}$ strangeness is in chemical equilibrium., Comment: 4 compact pages, 3 figures, Contribution to SQM2021 Online conference

We study the response of the electron mass to an externally applied electrical field. As a consequence of nonlinear electromagnetic (EM) effective action, the mass of a particle diminishes in the presence of an externally applied electric field. We consider modification of the muon anomalous magnetic moment g−2 due to electron loop insert in higher order. Since the virtual electron pair is in close proximity to the muon, it experiences strong field phenomena. We show that the current theory-experiment muon g−2 discrepancy could originate in the (virtual) electron mass nonperturbative modification by the strong muon EM field. The magnitude of the electron mass modification can be also assessed via enhancement of e+e−-pair production in strong fields.

I recall my “first hour” events following on my meeting in Fall 1968 in the classroom with my academic teacher and thesis mentor Prof. Dr. Dr. h.c. multiple Walter Greiner. My comments focus on the creation of the new “strong fields” domain of physics in Frankfurt. I argue that this was the research field closest to Walter’s heart during his lustrous academic career. I will describe the events that led on to Greiner’s course books, Walter’s actions leading to the rise of Frankfurt School of Theoretical Physics, and show how a stability principle defined his science.

We study a covariant classical model of neutral point particles with magnetic moment interacting with external electromagnetic fields. Classical dynamical equations which reproduce a correct behavior in the non-relativistic limit are introduced. We also discuss the non-uniqueness of the covariant torque equation. The focus of this work is on Dirac neutrino beam control. We present a full analytical solution of the dynamical equations for a neutral point particle motion in the presence of an external linearly polarized EM plane wave (laser) fields. Neutrino beam control using extremely intense laser fields could possibly demonstrate Dirac nature of the neutrino. However, for linearly polarized ideal laser waves we show cancellation of all leading beam control effects., 9 pages, 2 figures

Muon abundance is required for the understanding of several fundamental questions regarding properties of the primordial Universe. In this paper we evaluate the production and decay rates of muons in the cosmic plasma as a function of temperature. This allows us to determine when exactly the muon abundance disappears. When the Universe cools below the temperature $kT_\mathrm{disappear}\approx 4.135$ MeV the muon decay rate overwhelms production rates and muons vanish quasi-instantaneously from the Universe. Interestingly, we show that at $T_\mathrm{disappear}$ the muon number is nearly equal to baryon abundance., Comment: 10 pages APPB, 3 figures, Prepared for the 60th anniversary of the Cracow School of Theoretical Physics; v2 in press: typos corrected and computational details improved

We look from a theoretical perspective at the new phase of matter, quark-gluon plasma (QGP), the new form of nuclear matter created at high temperature and pressure. Here I retrace the path to QGP discovery and its exploration in terms of strangeness production and strange particle signatures. We will see the theoretical arguments that have been advanced to create interest in this determining signature of QGP. We explore the procedure used by several experimental groups making strangeness production an important tool in the search and discovery of this primordial state of matter present in the Universe before matter in its present form was formed. We close by looking at both the ongoing research that increases the reach of this observable to LHC energy scale $pp$ collisions, and propose an interpretation of these unexpected results., Comment: 142 pages, 46 graphic displays, accepted for publication in EPJ-ST

Es wird nachgewiesen, dass die Eigenzeit unter Lorentztransformationen invariant ist. Das Additionstheorem der Geschwindigkeiten wird fur den Spezialfall kollinearer Bewegungen und fur den allgemeinen Fall hergeleitet und eine Formel fur die Gesamtgeschwindigkeit bei beliebigen Geschwindigkeitsvektoren wird entwickelt. Es wird gezeigt, dass der Fresnelsche Mitfuhrungskoeffizient fur Licht in bewegten Flussigkeiten ebenso eine Konsequenz dieses Theorems ist wie die Maximalgeschwindigkeit \(|\boldsymbol {v}_\mathrm {max}

Wir entwickeln die grafische Darstellung der Lorentz-Koordinatentransformation und zeigen: 1) Der Zeitunterschied zwischen Ereignissen hangt vom Bezugssystem des Beobachters ab. 2) Eine bewegte Uhr geht in ihrem Ruhesystem langsamer als jede Laboruhr. Das ist die sogenannte Zeitdilatation. 3) Die Gleichzeitigkeit von zwei Ereignissen erfordert eine eindeutige Messvorschrift. Wir untersuchen die Konsistenz der Zeitdilatation mit der Lorentz-Koordinatentransformation.