Theory

Physics is not an edifice of thoughts which could be constructed purely by our minds. We cannot conceive the physical world and the basic laws of physics exclusively by deep thinking, pondering symmetries and establishing logical connections. On a fundamental level we have to make observations and collect information. We do not know what the minimal set of "basic experiments" might be – and if such a finite set exists at all – which is necessary to understand this world fully.

A physicist is neither a mathematician nor a philosopher. Mathematics is a language for physicists, extremely useful to implement symmetries, to connect fields far apart or to check the consistency of one's thoughts and quantify observations. Physics, however, has to arise from an understanding of nature, based on observations.

As a consequence, shouldn't a physicist do both, theory and experiment? Although great physicists in history succeeded with major achievements in both – G. Galileo, I. Newton, C. Huygens, E. Rutherford, R.H. Dicke – nowadays, the techniques in experiment and theory are often so involved and elaborate that it is beyond the possibilities of a single "standard" physicist to control them both. Yet it suggests itself to have experimentalists and theoreticians to do research jointly. This has been realized in many different approaches, from international cooperations between theoretical and experimental groups to joint projects of groups at the same institution.

At the chair for "Experimentalphysik VI" a self-contained theory group has been established recently, strongly interacting with two experimental groups within the same chair. This ensures a maximum cross section between scientists working in theory or in experiment. It provides a continuous exchange of ideas and, most importantly, it initiates joint efforts to engage in and resolve some of the exciting problems which recently emerged in condensed matter physics.