WG1: SMALLEST SCALES – VORTEX DYNAMICS AND DISSIPATION
WG1 co-leaders: Daniel Pęcak, Giulia Del Pace
WG1 focuses on the smallest length scales relevant to superfluid dynamics, where the internal structure of quantised vortices plays a central role and must be explicitly taken into account. At these scales, properties such as the vortex core structure strongly influence vortex motion, interactions, and dissipation mechanisms.
From an experimental perspective, WG1 addresses regimes in which the dynamics of a small number of vortices can be studied in detail, including their interactions with pinning sites and boundaries. These processes can be investigated in ultracold atomic gases, where vortices can be created and tracked with high precision, as well as in superfluid helium using tracer particles to visualise vortex motion.
On the theoretical and numerical side, the smallest scales are primarily addressed using microscopic approaches such as density-functional methods and Quantum Monte Carlo techniques. These tools provide first-principles insight into vortex structure, strongly interacting superfluids, and vortex reconnections in the presence of quantum turbulence, and are particularly relevant for systems connected to neutron star interiors. Complementary approaches include numerical simulations based on the Gross–Pitaevskii equation, as well as hydrodynamical methods, which offer a flexible framework that can be extrapolated to larger scales and astrophysical contexts.
This WG will therefore focus mainly on the questions:
How do vortex dynamics change across different (fermionic and bosonic) systems, and what is the role of the vortex core structure?
Which are the longitudinal and transverse forces acting on the vortices in these systems and how do they affect the global dynamics and dissipation in the overall fluid?
In addition, WG1 will address the microscopic aspects of the forces acting on vortices and their motion through inhomogeneous environments, contributing to a detailed understanding of dissipation processes at the smallest scales and providing essential input for the scale-bridging studies carried out in WG2 and WG3.
Contact: Daniel Pęcak (pecak@ifpan.edu.pl) · Giulia Del Pace (delpace@lens.unifi.it)