Supervisor: Michael Drewsen

Abstract

Within the theoretical framework of physics, fundamental constants enter as free parameters. The constants are assumed to have no variation in space and time, and their values have to be established from experiments. As a consequence, experimental searches for variations of fundamental constants represent tests of our fundamental physical theories.

After introducing the concept of fundamental constants, and elucidating the importance of checking for their constancy, this talk will present two complementary experimental approaches to check for temporal variations of the fine structure constant, namely, observations of quasar absorption lines and laboratory high-precision spectroscopy. The main focus will here be on the techniques allowing for measurements with unprecedented precision, before turning to results providing an upper bound to rate of change of the fine-structure constant.