Seminar Prof. Dr. Roman Schnabel

Titel: From interferometers using squeezed states of light to the generation of microscopic Schrödinger cat states.

In this talk, four types of experiments are presented in which continuous wave laser interferometers were combined with squeezing of the quantum uncertainty of light. First, a brief overview of the success story of squeezed light in gravitational wave detectors will be given. Our recent experiment improved the detection of the vibrational frequencies of a surface by suppressing the photon noise by 10 dB, even though the surface is highly absorbing. In another experiment, we measured the ensemble trajectory of the complex amplitude of an optical signal much more accurately than the Heisenberg uncertainty principle seems to allow. Finally, I present an experiment in which an ensemble of a squeezed vacuum state of light was converted into a superposition of two coherent states with a phase difference of 180° using a superconducting nanowire single photon detector. The latter state is usually understood as a microscopic Schrödinger cat state.

Lebenslauf
Roman Schnabel promovierte 1999 und war Feodor-Lynen-Forschungsstipendiat an der Australian National University, wo er über Quantenteleportation arbeitete. Von 2003 bis 2014 war er Professor an der Leibniz Universität Hannover und leistete Pionierarbeit bei der Squeezed-Light-Technologie, die heute in GEO600, LIGO und Virgo eingesetzt wird. Seit 2014 arbeitet er an der Universität Hamburg, am Institut für Quantenphysik. Er ist Mitbegründer der Noisy-Labs GmbH, Mitglied der LIGO Scientific Collaboration (LSC) und der Akademie der Wissenschaften in Hamburg. Zu seinen Auszeichnungen und Ehrungen gehört der APS 2013 Joseph F. Keithley Award.