CQD Special Seminars

1. June 2026 13:30

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.

CQD Colloquium

17. Juni 2026 16:30 Uhr

Physikalisches Institut, INF 226, K 1-3

Quantum vortices in Fermi superfluids: Structure, dynamics, and dissipation

Prof. Dr. Gabriel Wlazlowski , Faculty of Physics, Warsaw University of Technology

Quantum vortices are among the most prominent examples of topological excitations in superfluids. They arise in both bosonic systems, such as superfluid helium-4 and atomic Bose–Einstein condensates, and in fermionic systems, including superfluid helium-3, metallic superconductors, and neutron matter. While topology constrains many of their properties, key aspects of vortex behavior are governed by their internal structure, which depends on quantum statistics. In this seminar, I will review recent studies of quantum vortices in Fermi superfluids and contrast them with their bosonic counterparts. Particular attention will be given to the evolution of vortex core structure across the BCS–BEC crossover, spanning the transition from weak to strong coupling. I will then discuss how these structural changes influence vortex dynamics, focusing on the emergence of vortex inertia in Fermi systems and on microscopic mechanisms responsible for dissipation in their motion. The discussion will be supported by numerical results from density functional theory for Fermi superfluids, along with comparisons with experimental results for ultracold Fermi gases.

PreTalk: Ekaterina Vlasiuk (Institute for Theoretical Physics, Uni Heidelberg): "Enhancing superconductivity using thermal bosons"

contact

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

06221-54 19470

Ana Raspini