Effect of strong charge measurement on nonequilibrium tunneling in quantum dots from the perspective of the Anderson orthogonality catastrophe

The role of measurement in modifying quantum processes remains one of the most subtle yet essential problems in the pursuit of a full understanding of quantum systems. We describe an experiment that probes the effect of measurement via modifications in the tunneling process between a reservoir and a weakly-coupled quantum dot when the dot is capacitively coupled to a charge sensor, even when the charge sensor remains at or near equilibrium. The effect of the measurement is described in terms of the Anderson Orthogonality Catastrophe (AOC), whereby electrons in the leads of the charge detector reorganize with respect to an abrupt change in its local scattering potential. The consequence is an enhancement of non-resonant tunneling processes with respect to resonant ones in agreement with theoretical predictions. These results enable a direct estimation of the AOC exponent α for the coupled detector-quantum dot system.