Tracking ultracold many-body systems in real time

The variety of available probing techniques have established ultracold atoms as popular systems to study quantum many body physics. However, conventional approaches are usually destructive to the full ensemble, such that real time observation is challenging. In a recent publication, Manthey et al (2015 New J. Phys. 17 103024) present a novel method to overcome this challenge via weak measurements based on laser excitation to Rydberg states. Their technique is even sensitive to the local density by selecting long-range Rydberg molecules as the final state. This achievement provides a new tool to characterize ultracold atom many-body systems, which might be especially valuable to study time correlations in out-of-equilibrium situations.