A5013107443- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Theoretical and Computational Physics
- Physics of Superconductivity and Magnetism
- Computational Physics and Python Applications
- Pulsars and Gravitational Waves Research
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Complex Systems and Time Series Analysis
- Stochastic processes and statistical mechanics
- Neutrino Physics Research
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Quantum many-body systems
- Complex Network Analysis Techniques
- Material Dynamics and Properties
- Scientific Research and Discoveries
- nanoparticles nucleation surface interactions
- Geophysics and Gravity Measurements
- Particle accelerators and beam dynamics
Helsinki Institute of Physics
2016-2025
University of Helsinki
2016-2025
University of Bern
2022-2023
Aalto University
2022
University of Bonn
2022
Technical University of Munich
2019-2020
University of Southern Denmark
2016-2017
University of Jyväskylä
2009-2016
University of Stavanger
2016
University of Sussex
2016
We provide nonperturbative evidence for the fact that there is no hot first or second order electroweak phase transition at large Higgs masses, ${m}_{H}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}95$, 120, and 180 GeV. This means line of transitions separating symmetric broken phases small ${m}_{H}$ has an end point ${m}_{H,c}$. In minimal standard theory $70<{m}_{H,c}<95\mathrm{GeV}$ most likely ${m}_{H,c}\ensuremath{\approx}80\mathrm{GeV}$. If weakly coupled boson found to be...
We report on the first three-dimensional numerical simulations of first-order phase transitions in early Universe to include cosmic fluid as well scalar field order parameter. calculate gravitational wave (GW) spectrum resulting from nucleation, expansion, and collision bubbles low-temperature phase, for transition strengths bubble wall velocities covering many cases interest. find that compression waves continue be a source GWs long after have merged, new effect not taken properly into...
We present details of numerical simulations the gravitational radiation produced by a first order thermal phase transition in early universe. confirm that dominant source waves is sound generated expanding bubbles low-temperature phase. demonstrate have power spectrum with power-law form between scales set average bubble separation (which sets length scale fluid flow $L_\text{f}$) and wall width. The generate whose also has form, at rate proportional to $L_\text{f}$ square kinetic energy...
The free energy density, or pressure, of QCD has at high temperatures an expansion in the coupling constant g, known so far up to order ${g}^{5}.$ We compute here last contribution which can be determined perturbatively, ${g}^{6}\mathrm{ln}(1/g),$ by summing together results for 4-loop vacuum densities two different three-dimensional effective field theories. also demonstrate that inclusion new perturbative ${g}^{6}\mathrm{ln}(1/g)$ terms, once they are summed with unknown and...
The authors present the largest numerical simulations to date of first order phase transitions in early universe, explore shape acoustically generated gravitational waves and forecast prospects for detection with LISA. latter, a space-based wave observatory due launch about decade, is an ideal instrument observe signals from electroweak era, corresponding roughly 10 pico-seconds after big bang.
The most accurate calculation of the sphaleron rate --- responsible for baryon number changing processes has been made using large scale lattice simulations and mass recently discovered Higgs boson.
We investigate the potential for observing gravitational waves from cosmological phase transitions with LISA in light of recent theoretical and experimental developments. Our analysis is based on current state-of-the-art simulations sound cosmic fluid after transition completes. discuss various sources radiation, underlying parameters describing a variety viable particle physics models this context, clarifying common misconceptions that appear literature identifying open questions requiring...
With the physical Higgs mass standard model symmetry restoration phase transition is a smooth cross-over. We study thermodynamics of cross-over using numerical lattice Monte Carlo simulations an effective $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ $\text{gauge}+\text{Higgs}$ theory, significantly improving on previously published results. measure field expectation value, thermodynamic quantities like pressure, energy density, speed sound and heat capacity, screening...
We study the kinetics of first-order cosmological phase transitions assuming a four-parameter form for Higgs potential driving transition. This leads to phenomenological equation state electroweak matter with stable high-$T$ $T>{T}_{c}$ and low-$T$ $T<{T}_{c}$. The nucleation probability bubbles, both critical subcritical, is computed their growth coalescence simulated. show that they can grow as deflagrations detonations are unlikely. Possible front velocities entropy production studied....
We develop a discrete lattice implementation of the hard thermal loop effective action by method added auxiliary fields. use resulting model to measure sphaleron rate (topological susceptibility) Yang-Mills theory at weak coupling. Our results give parametric behavior in accord with arguments Arnold, Son, and Yaffe, are quantitative agreement Moore, Hu, M\"uller.
We measure the evolution of coupling constant using Schr\"odinger functional method in lattice formulation SU(2) gauge theory with two massless Dirac fermions adjoint representation. observe strong evidence for an infrared fixed point, where becomes conformal. $\ensuremath{\beta}$ function and as a energy scale.
We present a first-principle computation of the jet quenching parameter, which describes momentum broadening high-energy parton moving through deconfined state QCD matter at high temperature. Following an idea originally proposed by Caron-Huot, we explain how one can evaluate soft contribution to collision kernel characterizing this real-time phenomenon, analyzing certain gauge-invariant operators in dimensionally reduced effective theory (electrostatic QCD), be studied nonperturbatively via...
Making use of a dimensionally-reduced effective theory at high temperature, we perform nonperturbative study the electroweak phase transition in Two Higgs Doublet model. We focus on two phenomenologically allowed points parameter space, carrying out dynamical lattice simulations to determine equilibrium properties transition. discuss shortcomings conventional perturbative approaches based resummed potential - regarding insufficient handling infrared resummation but also need account for...
We study the stochastic gravitational wave background (SGWB) produced by freely decaying vortical turbulence in early Universe. thoroughly investigate time correlation of velocity field, and hence anisotropic stresses producing waves. With hydrodynamical simulations, we show that unequal function (UETC) Fourier components field is Gaussian difference, as predicted "sweeping" decorrelation model. introduce a model can be extended to wavelengths around integral scale flow. Supplemented with...