CQD Special Seminar

29. March 2019 15:00

Konferenzraum 4, 01.106, Physikalisches Institut, INF 226

Towards Quantum Information Processing with Atom-Filled Hollow-Core Fibres

Dr. Ben Sparkes
Institute for Photonics & Advanced Sensing, The University of Adelaide, Australia

Quantum information networks will deliver the capability for long-distance, provably-secure communications via quantum key distribution, as well as optical quantum computing. Our work aims to provide components for these quantum networks: our specific design makes use of hollow-core photonic crystal fibres (HCPCFs) filled with rubidium atoms, and are amenable to direct integration with current optical fibre technology. The tight transverse confinement (diameter of tens of microns) and extended interaction lengths (centimetres) of the HCPCFs provides an extremely optically dense medium, ideal for efficient quantum information storage and for achieving strong atom-mediated photon-photon interactions. I will present results from our experiments aiming for efficient, coherent and noiseless storage of high-bandwidth optical pulses in warm rubidium-filled HCPCFs using the off-resonance cascade absorption (ORCA) technique. We have also recently demonstrated the ability to load a record number of laser-cooled atoms into a hollow-core optical fibre and I will present our latest results towards achieving high efficiency, long-lived storage.

CQD Colloquium

29. Oktober 2025 16:30 Uhr

INF 226, K1-3 (Goldbox)

Exploring many-body physics with extended-range interactions

Dr Pascal Weckesser, Max Planck Institute of Quantum Optics

PreTalk: “Quantum droplets in Bose-Fermi mixtures”, Olivier Bleu, ITP, Heidelberg University

CQD Special Seminar

4. November 2025 14:15 Uhr

Kirchhoff-Institut für Physik, INF 227, Seminar Box 2

Josephson supercurrents and vortex dynamics in binary Bose-Einstein condensates

Dr. Alice Bellettini, Department of Applied Science and Technology, Politecnico di Torino, Italy

Quantum bosonic gases, due to their manipulability, provide the perfect platform for observing macroscopic quantum many-body phenomena. These can be for example quantum vortices (“topological defects”), being the hallmark of superfluidity, or Josephson supercurrents. Such collective effects have been recently employed in the context of quantum simulation and atomtronics. Here, I will present my research on the properties of massive quantum vortices in different configurations, and on vortex-supported supercurrents.

I will go through the inertial effects governing the massive vortex dynamics, to then focus on dipole scattering processes and on Josephson supercurrents as well as self-trapping effects in two- and many-vortex systems. Finally, I will conclude with an overview of the open questions on the topic.

contact

Prof. Dr. M. Weidemüller
Physikalisches Institut
Im Neuenheimer Feld 226
69120 Heidelberg

06221-54 19470

Ferman Alkasari