An important development in modern physics is the emerging capability for investigations of dynamical processes for open quantum systems in a regime of strong coupling for which individual quanta play a decisive role. Of particular signiÐcance in this context is research in cavity quantum electrodynamics which explores quantum dynamical processes for individual atoms strongly coupled to the ele...

P. Neilinger,1 S. N. Shevchenko,2, 3 J. Bogár,1 M. Rehák,1 G. Oelsner,4 D. S. Karpov,2 O. Astafiev,5, 6, 7 M. Grajcar,1, 8 and E. Il’ichev4, 9 Department of Experimental Physics, Comenius University, SK-84248 Bratislava, Slovakia B. Verkin Institute for Low Temperature Physics and Engineering, Kharkov, Ukraine V. Karazin Kharkov National University, Kharkov, Ukraine Leibniz Institute of Photoni...

Single excitons in semiconductor microcavities represent a solid state and scalable platform for cavity quantum electrodynamics, potentially enabling an interface between flying (photon) and static (exciton) quantum bits in future quantum networks. While both single-photon emission and the strong coupling regime have been demonstrated, further progress has been hampered by the inability to cont...

We present a class of gauge-invariant models of quantum electrodynamics with nonlocal interaction. The models have translation, Lorentz and gauge invariance and reduce to the conventional local quantum electrodynamics under the appropriate limit conditions, both the equations of motion of the charged particle and electromagnetic field obtained by the action principle lead to the normal form of ...

The lowest order processes described within quantum electrodynamics are free from the problem with infinities in the theory, and can be dealt with disregarding the need for charge and mass renormalization. This might indicate that the space-time description of these processes is not only consistent but also could give a privileged insight to the functioning of models provided by the theory. The...

Aspects of entropy and related thermodynamic analyses are discussed here that have been deduced in recent years in the area of classical electrodynamics. A motivating factor for most of this work has been an attempted theory of nature often called, “stochastic electrodynamics” (SED). This theory involves classical electrodynamics (Maxwell’s equations plus the relativistic version of Newton’s se...

Recently, it has been shown that the massless Schwinger model, namely two-dimensional massless spinor electrodynamics, may be solved exactly through the bosonisation of the massless fermion without having recourse to any gauge fixing procedure. With this background in mind, and the possible resolution of massless scalar electrodynamics in two-dimensional Minkowski spacetime compactified into th...

We perform a global parton analysis of deep inelastic and related hard-scattering data, including O(α QED) corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two important physical consequences. First, the different DGLAP evolution of u and d type quarks introduces isospin violation, i.e. u p = d n , which is found to be unambiguously in the...

A modification of electrodynamics is proposed, motivated by previously unremarked paradoxes that can occur in the standard formulation. It is shown by specific examples that gauge transformations exist that radically alter the nature of a problem, even while maintaining the values of many measurable quantities. In one example, a system with energy conservation is transformed to a system where e...

The construction of an alternative electromagnetic theory that preserves Lorentz and gauge symmetries, is considered. We start off by building up Maxwell electrodynamics in (3+1)D from the assumption that the associated Lagrangian is a gauge-invariant functional that depends on the electron and photon fields and their first derivatives only. In this scenario, as well-known, it is not possible t...