Name: The IIIrd Nordic Lattice Meeting 2023
Start: 2023-06-06T12:00:00+02:00
End: 2023-06-08T18:00:00+02:00
Location: UiS

Tuesday, 6 June
- Lunch
- Opening
  
  Conveners: Anders Tranberg (UiS - TN - IMF), Alexander Rothkopf (UiS TN IMF)
- Plenary session: Plenary I
  - 1
    
    Phase transitions, gravitational waves and the 2-Higgs doublet model
    
    Speaker: Kari Rummukainen (University of Helsinki)
    
    norlat23.pdf
  - 2
    
    Bubble nucleation and quantum initial conditions in classical statistical simulations
    
    Classical-statistical lattice simulations provide a useful approximation to out-of-equilibrium quantum field theory, but only for systems exhibiting large occupation numbers, and only for phenomena that are not intrinsically quantum mechanical in nature. In certain special circumstances, it can be appropriate to initialize such real-time simulations with quantum-like zero-point fluctuations. We will revisit these points, and investigate reports that quantum bubble nucleation rates in 1+1 dimensions can be computed through the classical evolution of such a quantum-like initial condition. We find that although intriguing, the reported numerical agreement between classical-statistical simulations and the quantum nucleation rate in 1+1 dimensions is a coincidence, which is not specific to this choice of initialisation, is parameter and lattice cut-off dependent and disappears as the number of space-dimensions increases from 1+1 to 2+1
    
    Speaker: Gerhard Ungersback (University of Stavanger)
    
    NordicLattice_Gerhard.pdf
  - 3
    
    Real scalar phase transitions: bubble nucleation, nonperturbatively
    
    In the Standard Model the electroweak phase transition is a crossover, but in many beyond the Standard Model theories the transition is of first order. Strong first order PTs could produce gravitational waves that might be detectable by the Laser Interferometer Space Antenna (LISA). Perturbation theory is commonly used to estimate the parameters that enter the calculation of gravitational wave spectra. However, perturbation theory is known to run into the infrared problem in the regime we are interested in and furthermore it is important to test the reliability of existing results. Here I will discuss our recent results where we studied a real singlet scalar model with a tree level potential barrier and performed nonperturbative simulations to determine the bubble nucleation rate. Our preliminary results show that higher orders in perturbation theory are necessary, and we expect our findings to allow calibration of the systematic uncertainty in perturbative results.
    
    Speaker: Anna Kormu (University of Helsinki)
    
    Lattice-Kormu.pdf
  - 4
    
    Lattice approaches to microphysical bubble dynamics
    
    In the study of cosmological phase transitions, even apparently weakly coupled theories develop strongly coupled sectors. For static equilibrium quantities, lattice methods have been developed to tackle this which are able to yield unambiguously correct results up to small statistical errors. For real-time quantities, the problem is more complicated. In this talk, I will review approaches to using lattice simulations for studying real-time bubble dynamics.
    
    Speaker: Oliver Gould (University of Nottingham)
    
    OG_Lattice.pdf
- Coffee Break
- Plenary session: Plenary II
  - 5
    
    Electroweak sphaleron in a magnetic field
    
    Speaker: Jaakko Annala (University of Helsinki)
    
    nordic_lat23_annala.pdf
Wednesday, 7 June
- Plenary session: Plenary III
  - 6
    
    Complex Lagevin and QCD Thermodynamics
    
    Speaker: Benjamin Jaeger (University of Southern Denmark)
    
    NoLa2023.pdf
- Coffee Break
- Plenary session: Plenary IV
  - 7
    
    Lefschetz Thimbles and real-time dynamics
    
    Speaker: Anders Tranberg (UiS - TN - IMF)
  - 8
    
    Mitigating the sign problem with line integrals
    
    Speaker: Rasmus Larsen
    
    Rasmus_Larsen_Nordic_2023.pdf
  - 9
    
    Machine Learning assisted real-time Complex Langevin
    
    Speaker: Alexander Rothkopf (UiS TN IMF)
    
    Complex_Langevin_Kernels_EXPORT.pdf
- Lunch
- Plenary session: Plenary V
  - 10
    
    Recent finite-volume developments in QED$_\textrm{L}$
    
    In this talk I will briefly present our recent RBC/UKQCD result for isospin-breaking corrections to leptonic decay rates. With the leading systematic uncertainty coming from unknown finite-volume effects, I will discuss the analytical evaluation of these at order $1/L^3$. This order is particularly complicated in certain formulations of finite-volume QED, and requires better understanding for future precision calculations in lattice QCD+QED.
    
    Speaker: Nils Hermansson-Truedsson (Lund University/The University of Edinburgh)
    
    NHTNordicLattice2023.pdf
  - 11
    
    Spectrum of QCD with one flavour
    
    Speaker: J Tobias Tsang (CP3-Origins, The University of Southern Denmark)
    
    OneFlavour.pdf
  - 12
    
    Complex heavy quark potential
    
    Speaker: Gaurang Parkar (University of stavanger)
    
    nordic_lattice2023.pdf
- Coffee Break
Thursday, 8 June
- Plenary session: Plenary VI
  - 13
    
    Entanglement Entropy and Lattice Gauge Theory
    
    Speaker: Tobias Rindlisbacher (University of Bern)
    
    entanglement_and_lgt_optimized.pdf
- Coffee Break
- Plenary session: Discussion - Lattice Activities in the Nordics
- Closing
  
  Conveners: Alexander Rothkopf (UiS TN IMF), Anders Tranberg (UiS - TN - IMF)