Strong QED Research Articles

Double Electron–Positron Pair Production with Two-electron Capture in Relativistic Heavy-ion Collisions

We calculated the cross section of double electron-positron pair production with two-electron capture for the collisions of Pb+Pb ions and we did our calculations at LHC energies. We applied a similar methodology for the calculation of bound-free electron-positron pair production. We used perturbation theory and implemented Monte Carlo integration techniques to calculate the lowest order Feynman diagrams. We also compared our double electron-positron pair production with two-electron capture cross section results obtained in the literature. These calculations may help us to learn more about strong QED.

Simultaneous production of lepton pairs in ultraperipheral relativistic heavy ion collisions

We calculate the total cross sections and probabilities of electromagnetic productions of electron, muon and tauon pair productions simultaneously. At the Large Hadron Collider (LHC), the available electromagnetic energy is sufficient to produce all kind of leptons coherently. The masses of muon and tauon are large, so their Compton wavelengths are small enough to interact with the colliding nuclei. Therefore, the realistic nuclear form factors are included in the calculations of electromagnetic pair productions. The cross section calculations show that, at the LHC energies, the probabilities of simultaneous productions of all kind of leptons are increased significantly compare to the RHIC energies. Experimentally, observing this simultaneous production can give us important informations about the strong QED.

PAIR PRODUCTION DENSITY IN STRONG QED

The current status of the research on pair production in strong QED is briefly reviewed not only for strong electric fields but also for strong magnetic fields in magnetically dominated astrophysical environment. A particular attention is paid to the spectral production number in the in- and out-state formalism and a possible prescription of the momentum integration is proposed to obtain the production density.

Strong Scalar QED in Inhomogeneous Electromagnetic Fields

Strong QED has attracted attention recently partly because many astrophysical phenomena have been observed to involve electromagnetic fields beyond the critical strength for electron-positron pair production and partly because terrestrial experiments will generate electromagnetic fields above or near the critical strength in the near future. In this talk we critically review QED phenomena involving strong external electromagnetic fields. Strong QED is characterized by vacuum polarization due to quantum fluctuations and pair production due to the vacuum instability. A canonical method is elaborated for pair production at zero or finite temperature by inhomogeneous electric fields. An algorithm is advanced to calculate pair production rate for electric fields acting for finite periods of time or localized in space or oscillating electric fields. Finally, strong QED is discussed in astrophysics, in particular, strange stars.

Vacuum persistence and inversion of spin statistics in strong QED

The vacuum persistence can be written as the Bose-Einstein distribution in spinor QED and as the Fermi-Dirac distribution in scalar QED exactly in a constant electric field and approximately in time-dependent electric fields. The inverse temperature is determined by the period of charged particle in the Euclidean time and the negative chemical potential by the ratio of the worldline instanton to the inverse temperature. The negativity of chemical potential is due to the vacuum instability under strong electric fields. The inversion of spin statistics in the vacuum persistence is a consequence of the Bogoliubov relations for fermions and bosons.

QED‐SCF, MCSCF, and coupled‐cluster methods in quantum chemistry

AbstractWe investigate a method of combining the techniques of quantum chemistry with QED. In our theory, we treat the N‐electron system and the Dirac sea on an equal footing; we regard both of them as the dynamical degrees of freedom of a many‐body system. After the introduction of our QED‐SCF method, the QED‐SCF solutions are classified on the basis of group‐theoretical operations such as time‐reversal, parity and O(3) rotational symmetry. The natural orbitals of general QED‐SCF solutions are determined by diagonalizing the first‐order density matrix. Thus, we obtain the possibility of treating the system under strong QED effect by the methods of quantum chemistry, such as QED‐MCSCF and QED coupled‐cluster approaches. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001

Critical coupling in strong QED with weak gauge dependence

We study chiral symmetry breaking in quenched QED 4, using a vertex ansatz recently proposed by Curtis and Pennington. Bifurcation analysis is employed in a general covariant gauge to investigate the gauge-dependence of the critical coupling for chiral symmetry breakdown. This turns out to be relatively minor, justifying the use of this vertex.