Workshop on the sign problem in QCD and beyond

Session

Friday morning

24 Jan 2025, 08:30

Lecture Hall 099 (ExWi Building) (University of Bern)

24. Testing dynamical stabilization of Complex Langevin simulations of QCD

Dénes Sexty

24/01/2025, 08:30

talk

We study complex Langevin simulations of a toy model as well as QCD, supplemented with a dynamical stabilization (DS) term, which was proposed to regularize the complexified process at lower temperatures. We compare the results to reweghting from zero chemical potential to measure the bias that the inclusion of the stabilization term causes, depending on its strength. At high temperatures the...

8. Diffusion models for complex Langevin dynamics

Prof. Gert Aarts (Swansea University)

24/01/2025, 09:15

talk

The probability distribution effectively sampled by a complex Langevin process for theories with a sign problem is not known a priori and notoriously hard to understand. Diffusion models, a class of generative AI, can learn distributions from data. In this contribution, we explore the ability of diffusion models to learn the distributions created by a complex Langevin process.

31. External and Dynamic Gauge Fields in Strong-Field QED

Óscar Amaro (GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal)

24/01/2025, 10:45

talk

Understanding nonperturbative regimes in Strong-Field Quantum Electrodynamics (SFQED) is essential for exploring fundamental processes in high-intensity laser-matter interactions. Despite significant progress in analyzing the Schwinger model, a systematic comparison of the underlying frameworks remains incomplete. In particular, direct contrasts between U(1) and Zₙ models within standard...

16. Towards Real-Time Observables from First Principles: Correlators in 3+1D Yang-Mills Theory

Kirill Boguslavski (TU Wien (AT))

24/01/2025, 11:30

talk

Real-time quantum field theories remain challenging due to the severity of the numerical sign problem. In this work, we successfully apply the complex Langevin (CL) method to SU(2) Yang-Mills theory in 3+1 dimensions. By introducing an anisotropic kernel, we stabilize simulations for real-time evolutions beyond the inverse temperature, enabling the first ab initio computations of unequal-time...