DQ-mat Jour Fixe at PTB Braunschweig

Location: PTB, Vieweg-Bau, Room 234 , Bundesallee 100, 38116 Braunschweig

Please requested to register your name on participants list with this link: https://seafile.projekt.uni-hannover.de/f/5a903832c3a0493a948f/

Please note PhD students financed by DQ-mat are expected to join, everyone else is expressly invited.

Programme of the Jour Fixe:

10-12 a.m. Report of Topical Group (TG)
„Designed quantum states for frequency metrology“ with presentations at least from A01, A10, B02, B03, B04
Vieweg-Bau, R234

12-1 p.m. Lunch
PTB casino

1-3:30 p.m. Lab tours
PTB labs

3:30-4 p.m. Coffee & Tea
Vieweg-Bau, R234

4-5 p.m. Colloquium Arno Rauschenbeutel (title & abstract below)
Vieweg-Bau, R234

7-9 p.m. Dinner with Arno Rauschenbeutel (please contact Nils Huntemann if you want to join)

Colloquium title: Rethinking Resonance Fluorescence: Fundamental Insights and Emerging Quantum Technologies
Abstract: Resonance fluorescence – the light emitted by a coherently driven two-level quantum emitter – has long served as a paradigm in quantum optics. In this talk, I will present two recent experimental investigations that reveal both the fundamental richness and the technological potential of this seemingly simple system. In the first part, I revisit the textbook notion that a single atom cannot scatter two photons simultaneously. Our results provide direct experimental evidence for an alternative quantum interference-based explanation, in which antibunching emerges from the coherent superposition of distinct two-photon scattering amplitudes. By selectively suppressing the coherently scattered component of the fluorescence spectrum, we isolate photon pairs that are simultaneously scattered by the atom, thereby validating a decades-old theoretical prediction. In the second part, I will show how resonance fluorescence can be harnessed as a highly efficient source of time-bin entangled photon pairs. Using a beam splitter followed by a coincidence detection, we transform the emission from a single atom into a stream of maximally entangled photon pairs, achieving a strong violation of a Bell inequality. Together, these experiments illustrate how resonance fluorescence – traditionally viewed as a fundamental textbook example – can be reimagined as a powerful resource for quantum information science.

Access data for the transfer: Zoom Access: https://us04web.zoom.us/j/932734874