Vortices with massive cores in quantum matter

Project Information

Vortexons

Grant agreement ID: 101062887

DOI

10.3030/101062887

Project closed

EC signature date 22 July 2022

Start date 9 January 2023

End date 8 January 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 181 152,96

Coordinated by

UNIVERSITAT POLITECNICA DE CATALUNYA
Spain

Periodic Reporting for period 1 - Vortexons (Vortices with massive cores in quantum matter)

Reporting period: 2023-01-09 to 2025-01-08

Summary of the context and overall objectives of the project

Quantum vortices, fundamental excitations in superfluid systems, are key to understanding superfluidity. Their presence in rotating quantum systems serves as direct evidence of superfluidity, distinguishing them from classical vortices through quantized circulation. Traditionally seen as empty-core structures, recent findings reveal that many vortices contain particles, giving them inertial mass. These massive vortices, or vortexons, exhibit distinct dynamical behaviors, opening new research directions. The Vortexons project developed a theoretical and numerical framework to study these topological excitations and their broader implications in quantum fluids.

By incorporating vortex core mass, the project addressed fundamental questions in superfluid vortex dynamics, exploring its effects on vortex motion, vortex-lattice stability, and the vortex core structure in Fermi superfluids. It also investigated Mott-superfluid transitions in vortexon clusters, the possibility to realize vortex-based bosonic Josephson junctions, and the interplay between ghost and massive vortices. These findings bridge fundamental quantum physics and applied research, with potential technological applications.

The project’s outcomes impact Bose-Einstein condensates, Fermi superfluids, liquid helium, superconductivity, and quantum turbulence, fostering both theoretical advancements and experimental relevance. Understanding vortex dynamics has direct implications for quantum technologies, including atomtronic circuits, high-performance superconductors, and quantum gyroscopes. The research aligns with Europe’s quantum strategy, reinforcing leadership in the Second Quantum Revolution and paving the way for breakthroughs with broad economic and societal impact.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The Vortexons project has significantly advanced our understanding of quantum vortex dynamics, particularly in systems where vortices acquire an inertial mass. Combining theory, numerical simulations, and analytical techniques, the project uncovered novel massive vortex behaviors, expanding knowledge in quantum fluids and emerging quantum technologies. Below is a summary of key achievements.

1. Theoretical and Numerical Investigation of Massive Vortex Dynamics

In May 2023, a study on ghost vortices in two-component BECs [Phys. Rev. Res. 5, 023109 (2023)] demonstrated that dual vortex necklaces emerge naturally in Bose-Bose mixtures when massive-vortex necklaces are present, with a proposed experimental protocol for their detection.

The impact of vortex core mass was further explored in August 2023 via a point-vortex model that incorporated the relative motion between vortices and their cores [Eur. Phys. J. Plus 138, 676 (2023)]. This study, benchmarked against Gross-Pitaevskii simulations, revealed that allowing for internal degrees of freedom leads to a more realistic vortex dynamics model.

2. Emergence of Novel Dynamical Phenomena in Massive Vortex Systems

The project also explored mass-driven dynamical effects. In August 2023, a study on massive vortices in a planar annulus [SciPost Phys. 15, 057 (2023)] demonstrated radial oscillations superimposed on precession, with a plasma orbit analogy providing analytical predictions.

In August 2024, this work was extended to explain the stabilization of vortex necklaces observed by LENS (Florence) [SciPost Phys. 17, 076 (2024)], identifying mass, dissipation, and system boundaries as key stabilizing factors. Additionally, the vortex dynamics on curved domains was addressed using conformal mapping techniques, leading to a full theoretical treatment published in [SciPost Phys. 17, 039 (2024)] in collaboration with Stanford University.

3. Discovery of a Massive-Vortex Bosonic Josephson Junction

A breakthrough in November 2024 was the first realization of a Bosonic Josephson Junction (BJJ) using two rotating massive vortices in a two-component BEC [Phys. Rev. Res. 6, 043197 (2024)]. This study revealed Josephson-like tunneling, stable oscillations, and macroscopic quantum self-trapping, bridging vortex physics and atomic quantum transport, with potential for atomtronic circuits.

4. Dynamical Signature of Vortex Mass in Fermi Superfluids

In October 2024, a preprint [arXiv:2410.12417] in collaboration with Warsaw University provided the first numerical confirmation of vortex mass effects in Fermi superfluids. Using large-scale time-dependent simulations, our study showed that vortices in Fermi superfluids are intrinsically massive, and hence exhibit transverse oscillations, providing a directly observable experimental signature of inertial effects in quantum vortices.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Key Scientific Advances & Future Research
The project provided the first systematic study of massive quantum vortices, revealing new dynamical behaviors such as cyclotron-like oscillations, Josephson tunneling of massive cores, and mass-induced stabilization in vortex lattices. A natural extension is to 3D systems, where vortices form filaments and tangles relevant to superfluid turbulence. A key question is how massive tracers like electron bubbles in liquid-helium experiments affect vortex-line density and energy decay in these systems. A crucial next step is the experimental confirmation of vortex mass effects in Fermi superfluids, predicted in [arXiv:2410.12417]. The main barrier is the resolution limit of current experiments, which makes tracking vortex trajectories with high precision challenging. Ongoing collaborations with experimental groups in Florence and Paris aim to bridge this gap.

Potential Applications & Impact
Understanding vortex pinning-depinning mechanisms is crucial for designing high-performance superconductors with optimized critical currents. The project’s result constitute the springboard for the design of a controlled cold-atom platform to simulate these effects, with direct implications for superconducting materials.

Challenges & Next Steps
Experimental resolution limitations remain a key challenge. Further research using high-performance computing (HPC) and sophisticated experimental setups is required. Progress will depend on expanding collaborations, securing HPC resources, and advancing experimental techniques to fully explore vortex mass effects.

Alignment with Europe’s Quantum Vision
The research contributes to the Quantum Technologies Flagship by enhancing the understanding of vortex matter, with implications for next-generation superconductors, atomtronic devices, and quantum sensors.

Schematic difference between a vortex and a vortexon.