CQD Special Seminar

25. April 2019 11:00

Seminarraum 2.404, Kirchhoff-Institut für Physik, INF 227

Molecular Optomechanics in the Quantum Regime: Phonon Quantum State Preparation and Readout

Professor Christophe Galland
EPFL, Lausanne, Switzerland


With the advent of quantum technologies, a quest toward the manipulation of mechanical oscillators in the quantum regime has been launched. I will present the experimental research of my group at the boundary between ultrafast spectroscopy, quantum optics and nanoscience, in which we prepare non-classical states of vibrations in nano- and molecular scale oscillators.

I will show how we can create a single quantum of vibration involving the collective motion of billions of atoms in a crystal [1,2], and how we can engineer a quantum superposition between two of these vibrational modes.  This non-classical state of oscillation features Bell correlations [3], the strongest form of correlation allowed by quantum mechanics.

I will explain how our technique can be extended to manipulate a broader range of nanoscale oscillators in the quantum regime, enabling new ways to process quantum information at ultrafast timescales, and opening a new window into quantum phenomena occurring in molecular and solid-state systems.

[1]  M. D. Anderson, S. T. Velez, K. Seibold, H. Flayac, V. Savona, N. Sangouard, and C. Galland, “Two-Color Pump-Probe Measurement of Photonic Quantum Correlations Mediated by a Single Phonon,” Phys. Rev. Lett. 120, 233601 (2018).

[2]  S. Tarrago Velez, K. Seibold, N. Kipfer, M. D. Anderson, V. Sudhir, C. Galland. “Birth and death of a single quantum of vibration” arXiv preprint arXiv:1811.03038v2 (2018).

[3]  S. Tarrago Velez et al., in preparation (2019).


 

up

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

4. November 2025 14:15 Uhr

tba

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