Dying experiments. A case study

Working experiments are the exception rather than the rule. Experimental setups seem to be broken pretty much all the time, and building, aligning, maintaining and repairing the apparatus form a much larger part of laboratory work then actual measurements.  Faults and failures of technical instruments increase over time, limiting the lifetime of experimental setups. The fragility of the apparatus exhibits the multitude of agencies contributing to an observation. These agencies act on cultural, social, material and political levels.

Here I will present the case of a dying quantum physics experiment, the Kapitza-Dirac-Talbot-Lau interferometer for molecules of the Vienna QuantumNanoPhyiscs group. This outstanding interferometer currently holds the world record for the largest particles exhibiting quantum delocalization and superposition, demonstrated by producing a nano-structured fringe pattern of these molecules.

I will discuss the lifecycle of the experiment and how it was shaped by funding, career interests and inherent limitations of the apparatus. Its performance decreased significantly after about ten years of successful operation, and the interference fringes began to fade. This becomes clearly visible when taking a look at the number of publications the experiment yielded. The failure of the apparatus triggered intense social conflicts within the group, driven by questions of power and differences in culture as well as experimental practice, but also influenced by external political pressure. Over a period of two years parts were exchanged and the interferometer realigned, giving insight into the interdependence of the material practices and the status of the interference-pattern as artifact. Finally it was declared dead and bid farewell with funeral rites.

Lukas Mairhofer is a experimental physicist and philosopher of science, holding PhDs in both disciplines. His research focuses on philosophical issues of modern physics, social conditions of experiments and the cultural impact of quantum mechanics.

He studied at the University of Vienna complemented by semesters abroad at Jawarhalal Nehru University, the University of Helsinki, UC Berkeley and the University of Konstanz as well as a secondment at the AEGIS collaboration at CERN. His research was supported by fellowships at the Internationale Forschungszentrum Kulturwissenschaften (Vienna) and the graduate schools "Das Reale in der Kultur der Moderne (Konstanz) as well as "Complex Quantum Systems" (Vienna). His thesis on "Bertolt Brecht's interference with Quantum Physics" won the doc.award 2015. Currently he is fellow of the MECS at Leuphana University Lüneburg.

Refreshments will be available 15 minutes prior to the start of the event.