Oct 16, 2024

Title: Quantum measurement through parametric amplification

Speaker: Prof. Dr. Maria Chekhova (Max-Planck Institute for the Science of Light, Erlangen, Germany)

Time: Oct. 16, 2024 (Wed) 4:30 pm

Zoom link (online only): https://kaist.zoom.us/j/87008936531?pwd=su0TmeVnnqXGbtvU1RbsVEGvaYQxLJ.1

 

Abstract

Quantum states of light are central to photonic quantum technologies, and their measurement is therefore very important. But quantum states are famous for being fragile. This is true for squeezed states of light, and even more true for non-Gaussian states – which are ultimately nonclassical but ubiquitous for some quantum information protocols. Fortunately, a nonlinear-optical device known as the optical parametric amplifier comes to rescue when measurement over a fragile quantum state is needed. It protects the measurement against optical losses and imperfect detection, enables addressing several modes at the same time, and can substitute homodyne detection with direct detection. In my talk I will show how, by applying parametric amplification, we can perform neat quantum measurements despite imperfect detection, characterize a multimode quantum state, and fully reconstruct the quantum state of a single mode.