Observation of detector-induced Anderson orthogonality catastrophe in quantum dots

In recent years many candidate setups have been proposed to support exotic quasi-particles, such as Majorana fermions (MFs), which may be relevant for quantum computing, but whether these  particles have been observed experimentally is currently a topic of a vivid debate. Entropy measurements can unambiguously separate these quasi-particles from other, simpler excitations. The entropy of a MFs is, for example, log2/2 (in units of the Boltzman constant), a fractional value that cannot be attributed to a localized excitation. In this talk I will describe recent theoretical and experimental progress in performing such measurements and show how the backaction of the measurement can lead to a tunable Anderson overlap catastrophe and Fermi edge singularity, in agreement with recent theory.