Quantum electrodynamics is a very developed field of study, with applications to the high-precision theory of atomic bound states, laser-matter interactions in the relativistic regime, and, on the low-energy side, the description of dynamic processes involving atoms and the quantized electromagnetic field.
In the following, an overview is given of the most important subfields of study, which have been given attention over the last years. However, the list given below does not include some recent development. Indeed, branching out from quantum electrodynamics of bound states, investigations have been carried out in the field of relativistic quantum mechanics and general relativity, atomic interaction and dynamic processes, quantum field theory of bound states, particle physics, and heavy-ion collision, and theoretical relativistic laser physics, work specifically connected with the determination of fundamental constants, as well as publications on the renormalization group and large-order perturbation theory. Exotic areas like the physics of sports and some considerations on numerical algorithm development complete the picture.
Recent developments include a comprehensive account of gravitational effects in the spectra of bound systems, and limitations of Einstein’s equivalence principle, given here, the analysis of atomic physics constraints on new particle models (see research article), and the identification of long-range tails in van der Waals interactions (see here). In general, the fields of interest have branched out a little more toward general relativity, in recent years, and borderline areas toward atomic physics. Probably, the most important result obtained in recent years concerns the equivalence principle for antiparticles, which has been investigated and, perhaps, conclusively demonstrated here. Furthermore, problems connected to the interaction of atoms, including those in metastable states, with surfaces (see our research article), have been considered. Quantum electrodynamics is sometimes characterized as a theory that describes somewhat exotic effects, tiny corrections which are important mainly for high-precision experiments. This is not the case, as shown in recent works. The quantum theory of blackbody and non-contact van der Waals friction, which is important for astrophysical processes, has been considered here. The surprising conclusion is that the so-called one-loop quantum electrodynamic “correction” in this case dominates over the tree-level term.
A further example where insight into quantum electrodynamic processes is crucial for the analysis of dynamic processes involving bound states concerns two-photon decays from highly excited states. The problem is that in typical cases, virtual states of lower energy than the decaying state, but higher energy than the ground state, exist which can be reached via a dipole transition. One thus has to separate the coherent contribution to the two-photon decay rate, from the sequential one-photon transition via the intermediate (virtual state). The latter process is also known as a cascade. This problem has been addressed in a number of publications, including this one and here, following an initial account given as a fast-track communication.