laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Seminar, 20th October 2016 (11h salle L363/L365)

Emmanuel Flurin (Department of Physics, University of California, Berkeley)
Dynamics of Simultaneously Measured Non-Commuting Observables

In quantum mechanics, measurement restores a classical notion of reality via collapse of the wavefunction, which yields a precisely defined outcome. On the other hand, the Heisenberg uncertainty principle dictates that incompatible observables, such as position and momentum, cannot both take on arbitrarily precise values. But how does a wavefunction evolve when two such quantities are probed simultaneously, and how does the uncertainty principle dynamically inhibit precise measurement outcomes ?

In this talk I will present a novel detection scheme that allows control over the measurement operators of multiple readout channels of a superconducting qubit. I will show how the uncertainty principle governs the dynamics of the state by enforcing a lower bound on the measurement-induced disturbance, inhibiting wavefunction collapse and consequently leading to persistent diffusion. I will also discuss the ramifications of this scheme in the context of quantum control and metrology applications.