Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks.

We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly improve the constraints on transient variations of the fine structure constant. For example, we constrain the variation in alpha to ~10^4 km) objects.