The Production of a Femtosecond Pulse

• In Event: The Temporal Repertoire

Abstract

Imagining a femtosecond via human cognitive faculties is close to an impossible exercise: it is one quadrillionth of a second (i.e. 10-15 of a second). It is also a standard time unit in molecular dynamics, that is, in the study of the movement of atoms and molecules. The femtosecond pulse has become the operational unit in X-Ray Free-Electron Laser (XFEL) experiments that generate 3-D simulations of biomolecular behaviour. One of the goals of this avenue of research in physics is to determine the structure and variability of biological viruses and macromolecules in their natural environment. XFEL potentially allows a breakthrough in the understanding of structure and dynamics of biomolecules. This means that it, for instance, enables unprecedented forensics of how disease-causing viruses manipulate human cells and how drugs could work against them. The femtosecond, however, emanates both from deeply internalized social techniques that apprehend time and from diverse and antagonistic non-human times. Following Latour (2005) this paper argues that femtosecond pulses rest on socially embedded conventional technical apparatuses that enable time-measuring and time-recording (i.e. chronometric devices such as clocks and calendars) and that non-human temporalities of biological (i.e. the life of the virus) and institutional (i.e. availability/allocation of beamtime/experimental time in labs) nature need to be considered. The overall implication of this paper’s analysis is that even if the femtosecond – as any other unit capturing “real-time” processes – seems so surreal, it is in fact grounded or “folded” in several im/mutable temporalities that need to be strategically aligned to reach it. 

Author

• Filip Vostal, Institute of Philosophy of the Czech Academy of Sciences