Physics Department Colloquia
Events on Friday, March 3rd, 2017
- Quantum measurement in superconducting circuits: mapping quantum trajectories from spontaneous emission.
- Time: 3:30 pm
- Place: 2241 Chamberlin hall
- Speaker: Kater Murch, Washington University, St. Louis
- Abstract: Spontaneous emission of light by atoms is one of the most basic light-matter interactions and is responsible for the majority of the visible light that we see. The process of spontaneous emission can also be viewed in the context of quantum measurement, the light-matter interaction entangles the atom with the electromagnetic field and subsequent measurements of the field convey information about the state of the atom. For example, if the emitted light is detected in the form of energy quanta, the detection of an individual photon results in an instantaneous jump of the atom to a lower energy state. However, if the emission is instead measured with a detector that is not sensitive to quanta, but rather the amplitude of the field, the atom’s state will undergo different dynamics over finite timescales.
In this talk, I will review how recent progress in the fabrication and control of quantum coherent superconducting circuits has enabled experiments that probe the fundamental physics of quantum measurement. These range from the observation of non-classical weak values to the generation of entanglement through measurement and the tracking of individual quantum trajectories. I will then describe our recent experiments that focus on the special case of spontaneous emission, revealing rich dynamics associated with measurement, and how we are harnessing these dynamics to extend thermodynamics into the regime of single quantum systems.
- Host: Justin Vandenbroucke