Events: Colloquia, Seminars, Workshops, and Conferences

Present Announcements:

Center for Quantum Dynamics Colloquium

20. Mai 2026 16:30 Uhr

Physikalisches Institut, INF 226, K 1-3

Ultracold lithium-chromium mixtures: From mass-asymmetric fermionic matter to paramagnetic molecules

Dr. Matteo Zaccanti, INO-CNR & LENS, Physics Department, University of Florence

Quantum mixtures of different atomic species represent compelling frameworks for a variety of fundamental studies and quantum-technological applications, ranging from the exploration of exotic few- and many-body phenomena to the realization of novel molecular species in the ultracold regime.

Here, I will first provide a general overview of the activities of our lab, primarily based on a novel Fermi-Fermi mixture of ⁶Li alkali and ⁵³Cr transition-metal atoms, and currently focusing onto two main research topics: realization of quantum gases of LiCr molecules, and investigation of strongly interacting fermionic matter in presence of a large mass asymmetry.

I will then discuss in more detail a recent study of transport dynamics of a small sample of ultracold lithium atoms – acting as light impurity particles – released into a large, ideal gas of chromium – that plays the role of a bath of heavy, point-like scatterers. Under strong interspecies interactions, by lowering the temperature we unveil a crossover from normal diffusion to subdiffusion. Simultaneously, a localized fraction emerges in the lithium gas, displaying no discernible dynamics over hundreds of collision events. Our findings, incompatible with a conventional Fermi-liquid picture, are instead captured by a model of a matter wave propagating through a (quasi-)static disordered landscape of point-like scatterers. These results point to a key, enhanced role of quantum interference in heavy-light atomic mixtures, which emerge as versatile platforms for exploring disorder-free localization phenomena solely driven by a large mass difference.

 PreTalk: Tobias Hammel, Physikalisches Institut, Uni Heidelberg: "Now you see them, now you don't: Hiding atoms with light"

Forthcoming talks during the current term

Past talks

CQD Special Seminars

1. Juni 2026 13:30 Uhr

Physikalisches Institut, INF 226, K 1-3

Probing and controlling dipolar many-body dynamics in disordered spin ensembles in diamond

Jenny Jiang, University of Cambridge

The dynamics of interacting, disordered quantum systems is a central topic in many-body physics. Dense ensembles of nitrogen-vacancy centres (NVs) in diamond provide a unique platform to realise a strongly interacting, intrinsically disordered spin systems with long-range dipolar interactions at room temperature. This enables access to rich many-body physics including thermalisation, non-equilibrium dynamics, and dimensional crossovers.

In this talk, I will first introduce the NV as a controllable spin platform and discuss how interactions within an ensemble give rise to complex many-body behaviour. I will then explain how we can probe the spin environment and selectively control interactions with Hamiltonian engineering techniques. A central challenge in using these systems as quantum simulators is the lack of precise knowledge of the interaction within a sample. I will present my work on using tailored pulse sequences as spectroscopic tools to characterise the spin bath and extract key parameters governing the system dynamics. This provides a route towards quantitative control of disordered spin ensembles and the exploration of emergent many-body physics in solid-state quantum simulators.

 

9. Juni 2026 16:30 Uhr

Microscopic Structured Light-Matter Coupling for Atomic and Molecular Quantum Control

Georgios Koutentakis, Institute of Science and Technology Austria

Optical tweezers and tightly focused beams are now central tools in atomic and molecular quantum science, but many current platforms operate in regimes where plane-wave, paraxial, and point-particle approximations are no longer sufficient. In this talk, I will outline how our previous work on structured light-matter interaction provides the technical basis for a research program that treats the microscopic structure of optical fields as a genuine control resource, rather than as a hidden experimental detail.

The first part of the program focuses on atoms and molecules in realistic high-numerical-aperture tweezer fields. Longitudinal field components, polarization gradients, tensor light shifts, and spatial phase structure can generate internal-motion entanglement, decoherence, leakage, and heating. A predictive microscopic theory is therefore needed to identify dominant error channels and design mitigation strategies. For molecules, the rotational degree of freedom amplifies these effects, but also opens new possibilities for rotational control and engineered dipolar interactions. The second part applies these ideas to the trap-resolved assembly of microwave-dressed molecular complexes. Here, structured optical confinement and microwave-induced interactions define light-induced potential energy surfaces for coherent dimer and trimer formation. I will discuss how wavepacket methods, especially multilayer MCTDH, can be used to model and optimize these processes, and why Heidelberg provides an ideal environment for developing this direction.

 

Past talks