Thesis supervisor: András Vukics
Location of studies (in Hungarian): Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Institute for Solid State Physics and Optics, Department of Quantum Optics and Quantum Information Abbreviation of location of studies: MTA
Description of the research topic:
Recently, the interest in the multipolar gauge of quantum electrodynamics has been revived following a revisit of the problem of the feasibility of the Dicke phase transition with atoms in the electromagnetic field (cf. e.g. Phys.Rev.Lett.112:073601[2014]). The multipolar gauge has been worked out for arbitrary topology of the domain of the electromagnetic field. Regarding this fundamental work, several open questions remain, such as the role of cohomological fields and the nature of the Lamb shift in this gauge. The behaviour of the system of atoms and field as a many-body system can further be studied including atom-atom interaction by many-body methods, such as the renormalization group treatment. The developed formalism can then be used to study other candidate systems for ultra-strong coupling, such as a two-dimensional electron gas trapped in semiconductor heterostructures and circuit QED. Besides learning the sound quantum electrodynamical foundations of the interaction of matter with light, the candidate has the opportunity to join the quest for achieving ultra-strong coupling between light and matter on the quantum scale.
Further requirements: Sound foundations in electrodynamics and quantum mechanics, and some understanding of quantum electrodynamics and the canonical formalism of fields