arXiv subjects

Johann Rafelski

Publications and source records attributed to Johann Rafelski.

At least 37 records · Page 2Linked to original sources

arXiv2023

Electron-positron plasma in BBN: damped-dynamic screening

We characterize in detail the very dense $e^- e^+ γ$ plasma present during the Big-Bang Nucleosynthesis (BBN) and explore how it is perturbed electromagnetically by \lq\lq impurities, {\it i.e.\/}, spatially dispersed protons and light nuclei undergoing thermal motion. The internuclear electromagnetic screened potential is obtained (analytically) using the linear response approach, allowing for the dynamic motion of the electromagnetic field sources and the damping effects due to plasma component scattering. We discuss the limits of the linear response method and suggest additional work needed to improve BBN reaction rates in the primordial Universe. Our theoretical methods to describe the potential between charged dust particles align with previous studies on planetary and space dusty plasma and could have significant impact on interpretation of standard cosmological model results.

astro-ph.CO↗

arXiv2023

Matter-antimatter origin of cosmic magnetism

We explore the hypothesis that the abundant presence of relativistic antimatter (positrons) in the primordial universe is the source of the intergalactic magnetic fields we observe in the universe today. We evaluate both Landau diamagnetic and magnetic dipole moment paramagnetic properties of the very dense primordial electron-positron $e^{+}e^{-}$-plasma, and obtain in quantitative terms the relatively small magnitude of the $e^{+}e^{-}$ magnetic moment polarization asymmetry required to produce a consistent self-magnetization in the universe.

hep-ph↗

arXiv2023

A short survey of matter-antimatter evolution in the primordial universe

We offer a survey of the matter-antimatter evolution within the primordial Universe. While the origin of the tiny matter-antimatter asymmetry has remained one of the big questions in modern cosmology, antimatter itself has played a large role for much of the Universe's early history. In our study of the evolution of the Universe we adopt the position of the standard model $Λ$-CDM Universe implementing the known baryonic asymmetry. We present the composition of the Universe across its temperature history while emphasizing the epochs where antimatter content is essential to our understanding. Special topics we address include the heavy quarks in quark-gluon plasma (QGP), the creation of matter from QGP, the free-streaming of the neutrinos, the vanishing of the muons, the magnetism in the electron-positron cosmos, and a better understanding of the environment of the Big Bang Nucleosynthesis (BBN) producing the light elements. We suggest but do not explore further that the methods used in exploring the early Universe may also provide new insights in the study of exotic stellar cores, magnetars, as well as gamma-ray burst (GRB) events. We describe future investigations required in pushing known physics to its extremes in the unique laboratory of the matter-antimatter early Universe.

hep-th↗

arXiv2023

Improving Euler-Heisenberg-Schwinger effective action with dressed photons

We implement a longstanding proposal by Weisskopf to apply virtual polarization corrections to the in/out external fields in study of the Euler-Heisenberg-Schwinger effective action. Our approach requires distinguishing the electromagnetic and polarization fields based on mathematical tools developed by Białynicki-Birula, originally for the Born-Infeld action. Our solution is expressed as a differential equation where the one-loop effective action serves as input. As a first result of our approach, we recover the higher-order one-cut reducible loop diagrams discovered by Gies and Karbstein.

hep-ph↗

arXiv2023

Born-Infeld nonlinear electromagnetism in relativistic heavy ion collisions

We study the effect of the limiting field strength of Born-Infeld electromagnetism on the dynamics of charged particle scattering. We formulate the Born-Infeld limiting field in an invariant manner, showing that it is the electric field-dominated eigenvalue `$a$' of the field tensor $F^{μν}$ which is limited rather than the individual field vectors. Heavy ion collisions in particular provide uniquely large values of the field invariants that appear in the BI action, amplifying nonlinear effects. Thus ``$a$'' is the dominant input into the force between heavy ions that we use to compute the scattering angle as a function of impact parameter. We evaluate the BI effects, showing relevance at small impact parameters and exhibiting their dependence on the value of the limiting field strength.

nucl-th↗

arXiv2022

Singular properties of QED vacuum response to applied quasi-constant electromagnetic fields

Employing the Bogoliubov coefficient summation method and introducing the gyromagnetic ratio $g\neq 2$ we derive an explicit functional form of $\mathfrak{Im}V^\mathrm{EHS}_g$, the imaginary part of Euler-Heisenberg-Schwinger (EHS) type effective action. We show that $\mathfrak{Im}V^\mathrm{EHS}_g$ is periodic in $g$ for any (quasi-)constant electromagnetic field configuration, and equal to the imaginary part obtained using a periodic in $g$ Ramanujan integrand in the proper time representation of $V^\mathrm{EHS}_g$. This validates the Ramanujan representation of $V^\mathrm{EHS}_g$ for both real and imaginary parts and allows writing the effective action in a suitably modified Schwinger proper time format. As a function of the ratio $b/a$ between ${\mathcal{B}} \to b$ and ${\mathcal{E}}\to a$ covariant generalizations of EM fields, we explore the singular properties of $\mathfrak{Im}V^\mathrm{EHS}_g$ at $g=2\pm 4k, k=0,\pm1,\pm2\ldots$ involving the pseudoscalar $ab\equiv \vec{\mathcal{E}}\cdot\vec{\mathcal{B}}$ in perturbative and nonperturbative behavior. We study the $e^-e^+$-decay vacuum instability, incorporating the physical value of $g-2$ vertex diagrams when summing infinite irreducible loops. We obtain an effective expansion parameter $χ_b=αb/2a$ ($α=e^2/4π$), characterizing the onset of nonperturbative in $g-2$ suppression of vacuum instability. We demonstrate the $χ_b$ domains for which perturbative expansion in $α$ breaks down: The EM vacuum subject to critical electric field strength is stabilized in magnetic-dominated \lq magnetar\rq\ environments. Considering separately the case of ${\mathcal{E}}$ and ${\mathcal{B}}$ fields, we generalize to all $g$ the temperature representation of the $V^\mathrm{EHS}_g$ effective action.

hep-ph↗

arXiv2022

A Cusp in QED at g=2

We explore nonperturbative properties of QED allowing a gyromagnetic ratio $g\ne g_{\rm D}\equiv 2$. We study the effective action $V_{\mathrm{eff}}$ for an arbitrarily strong constant and homogeneous field. Using the external field method, we find a cusp as a function of the gyromagnetic factor $g$ in: a) The QED $b_0$-renormalization group coefficient; b) A subclass of light-light scattering coefficients obtained in the long wavelength limit expansion. We recognize possibility of asymptotic freedom in an Abelian theory for certain domains of $g$.

hep-ph↗

arXiv2022

Emergence of periodic in magnetic moment effective QED action

We evaluate for the inhomogeneous static electric Sauter step potential the imaginary part of the emerging homogeneous in electric field effective Euler-Heisenberg-Schwinger action sourced by vacuum fluctuations of a charged particle with magnetic moment of arbitrary strength. The result is convergent for all values of gyromagnetic ratio $g$, periodic in $g$, with a cusp at $g=2$. We consider the relation to the QED beta-function which is also found to be periodic in $g$. We confirm presence of asymptotic freedom conditions using this novel method and document a wider range of $g$-values for which asymptotic freedom is present.

hep-ph↗

arXiv2022

Dynamic Magnetic Response of Quark-Gluon Plasma to Electromagnetic Fields

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.

hep-ph↗

arXiv2022

Radiation reaction and limiting acceleration

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.

hep-ph↗

arXiv2021

Cosmological Strangeness Abundance

We investigate the strange particle composition of the early Universe in the hadron epoch $T_h\approx 150\ge T\ge 10$\,MeV. We study strangeness yield in thermal and chemical equilibrium constrained by prescribed entropy per baryon in a charge neutral and strangeness neutral $\langle s-\bar s\rangle$ Universe. Turning to kinetic processes in a Hubble expanding Universe, we determine conditions at which individual strangeness producing reactions fall out of detailed balance between decay and back-reaction strangeness production rates in presence of decreasing temperature $T$; we allow for weak, electromagnetic, and strong interaction processes. The weak interaction $μ^\pm+ν_μ\rightarrow K^\pm$ freezeout is at $T_f^{K^\pm}=33.8\,\mathrm{MeV}$; the electromagnetic process $l^-+l^+\rightarrowϕ$ freezeout is at $T_f^ϕ=23\sim25\,\mathrm{MeV}$; and the hadronic reaction $π+π\rightarrow K$ freezeout is at $T_f^K=19.8\,\mathrm{MeV}$.

hep-ph↗

arXiv2021

Particle production at a finite potential step: Transition from Euler-Heisenberg to Klein paradox

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.

hep-ph↗

arXiv2021

Current-Conserving Relativistic Linear Response for Collisional Plasmas

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 $κ$. 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 $κ$. Finally, we study the dispersion relations for the longitudinal and transverse poles of the propagator. We show that for $κ> 2ω_p$, where $ω_p$ is the plasma frequency, the plasma wave modes are overdamped. In the opposite case, $κ\ll ω_p$, the propagating plasma modes are weakly damped.

physics.plasm-ph↗

arXiv2021

Reactions Governing Strangeness Abundance in Primordial Universe

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 $μ^\pm+ν_μ\rightarrow K^\pm$, $l^-+l^+\rightarrowϕ$, and $π+π\rightarrow K$ 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.

hep-ph↗

arXiv2021

Motion of classical charged particles with magnetic moment in external plane-wave electromagnetic fields

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.

physics.class-ph↗

arXiv2020

Radiation reaction friction: Resistive material medium

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.

hep-ph↗

arXiv2020

Electron EM-mass melting in strong fields

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 \textit{non-perturbative} 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.

hep-ph↗

arXiv2020

Possibility of bottom-catalyzed matter genesis near to primordial QGP hadronization

We study bottom flavor abundance in the early Universe near to a temperature $T_\mathrm{H}\simeq150\,\mathrm{MeV}$, the condition for hadronization of deconfined quark-gluon plasma (QGP). We show bottom flavor abundance nonequilibrium lasting microseconds. In our study we use that in both QGP, and the hadronic gas phase (HG) $b$ and $\bar b$ quarks near $T_\mathrm{H}$ are bound in B-mesons and antimesons subject to $CP$ violating weak decays. A coincident non-equilibrium abundance of bottom flavor can lead to matter genesis at required strength: a) The specific thermal yield per entropy is $n_b^{th}/σ=10^{-10}\sim10^{-13}$. b) Considering time scales, millions of cycles of B-meson decays, and $b\bar b$-pair recreation processes occur.

hep-ph↗