A5008552432- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Theoretical and Computational Physics
- Black Holes and Theoretical Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Stochastic processes and statistical mechanics
- Quantum many-body systems
- Distributed and Parallel Computing Systems
- Stochastic processes and financial applications
- Physics of Superconductivity and Magnetism
- Scientific Computing and Data Management
- Markov Chains and Monte Carlo Methods
- Random Matrices and Applications
- Quantum chaos and dynamical systems
- Hepatitis C virus research
- Spectral Theory in Mathematical Physics
- Cosmology and Gravitation Theories
- Parallel Computing and Optimization Techniques
- Computational Physics and Python Applications
- Algebraic structures and combinatorial models
- Complex Systems and Time Series Analysis
- Statistical Mechanics and Entropy
- Gaussian Processes and Bayesian Inference
- Medical Imaging Techniques and Applications
University of Parma
2015-2024
Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Parma
2013-2024
University of Bonn
2023
Bielefeld University
2008-2022
Candiolo Cancer Institute
2020
Istituti di Ricovero e Cura a Carattere Scientifico
2020
University of Turin
2020
University of Edinburgh
2019
Michigan State University
2019
Istituto Nazionale di Fisica Nucleare
2019
It is sometimes speculated that the sign problem afflicts many quantum field theories might be reduced or even eliminated by choosing an alternative domain of integration within a complexified extension path integral (in spirit stationary phase method). In this paper we start to explore possibility somewhat systematically. A first inspection reveals presence difficulties but - quite surprisingly most them have interesting solution. particular, it possible regularize lattice theory on...
We present the first practical Monte Carlo calculations of recently proposed Lefschetz thimble formulation quantum field theories. Our results provide strong evidence that numerical sign problem afflicts models with complex actions can be softened significantly by changing domain integration to or approximations thereof. study interacting scalar theory (relativistic Bose gas) in lattices size up 8^4 using a computationally inexpensive approximation thimble. are excellent agreement known...
We present a calculation of the net baryon number density as function imaginary chemical potential, obtained with highly improved staggered quarks (HISQ) at temporal lattice extent $N_τ=4,6$. construct various rational approximations data and discuss how poles in complex plane can be determined from them. compare our results singularities potential to theoretically expected positions Lee-Yang edge singularity vicinity Roberge-Weiss chiral phase transitions. find temperature scaling that is...
We explore the highly nonperturbative hot region of QCD phase diagram close to ${T}_{c}$ by use an imaginary chemical potential $\ensuremath{\mu}$ which avoids sign problem. The simulations four flavors staggered fermions and are carried out on a ${16}^{3}\ifmmode\times\else\texttimes\fi{}4$ lattice. number density quark susceptibility consistent with critical behavior associated transition line in negative ${\ensuremath{\mu}}^{2}$ half-plane. compare analytic continuation these results...
We propose an efficient method to compute the so-called residual phase that appears when performing Monte Carlo calculations on a Lefschetz thimble. The is stochastic and its cost scales linearly with physical volume, number of estimators quadratically length extra dimension along gradient flow. This drastic improvement over previous estimates computing phase. also report basic tests correctness scaling code.
We apply the Lefschetz thimble formulation of field theories to a couple different problems. first address solution complex 0-dimensional phi^4 theory. Although very simple, this toy-model makes us appreciate few key issues method. In particular, we will solve model by correct accounting all thimbles giving contribution partition function and discuss number algorithmic solutions simulate (simple) model. then move chiral random matrix (CRM) This is somehow more realistic setting, once again...
We propose inverse renormalization group transformations within the context of quantum field theory that produce appropriate critical fixed point structure, give rise to flows in parameter space, and evade slowing down effect calculations pertinent criticality. Given configurations two-dimensional ϕ^{4} scalar on sizes as small V=8^{2}, we apply rescaled systems size up V^{'}=512^{2} which utilize extract two exponents. conclude by discussing how approach is generally applicable any method...
QCD in 0+1 dimensions is numerically solved via thimble regularization. In the context of this toy model, a general formalism presented for SU(N) theories. The sign problem that theory displays genuine one, stemming from (quark) chemical potential. Three stationary points are present original (real) domain integration, so contributions all thimbles associated to them be taken into account: we show how semiclassical computations can provide hints on regions parameter space where absolutely...
We report updated results on the determination of Lee-Yang edge (LYE) singularities in $N_f = 2 + 1$ QCD using highly improved staggered quarks (HISQ) with physical masses $𝑁_\tau 4, 6, 8$ lattices. The singularity structure complex $\mu_B$ plane is probed conserved charges calculated at imaginary $\mu_B$. location determined by studying (uncancelled) poles multi-point Padé approximants. show that close to Roberge-Weiss (RW) transition, LYE scales according $3$-$d$ $Z(2)$ universality class....
We report on status and perspectives of the International Lattice Data Grid. ILDG was established some twenty years ago as a community-wide initiative to enable sharing gauge configurations generated by many major lattice collaborations. After phase in which availability usage services had degraded, an effort modernize reactivate 2.0 has been started. The made important progress we can look forward larger fully FAIR data sets becoming available wider audience.
We present a numerical calculation of the Lee-Yang and Fisher zeros 2D Ising model using multipoint Padé approximants. perform simulations for with ferromagnetic couplings both in absence presence magnetic field cluster spin-flip algorithm. show that it is possible to extract genuine signature theory through poles magnetization specific heat, method. approximants compare their scaling known results. verify circle theorem associated well behavior zeros. our finite volume analysis done at...
We perform accurate numerical experiments with fully connected one hidden layer neural networks trained a discretized Langevin dynamics on the MNIST and CIFAR10 datasets. Our goal is to empirically determine regimes of validity recently derived Bayesian effective action for shallow architectures in proportional limit. explore predictive power theory as function parameters (the temperature T, magnitude Gaussian priors λ_{1}, λ_{0}, size N_{1}, training set P) by comparing experimental...
Imaginary baryon number chemical potential simulations are a popular workaround for the (in)famous sign problem plaguing finite density QCD studies on lattice. One is necessarily left with of analytically continuing results to real values $\mu_B$. In framework Bielefeld Parma Collaboration, we have in recent years studied multi-point Pad\'e description net computed as function imaginary potential. While our main emphasis has till now been determination Lee-Yang singularities, method per se...
Taylor expansion at $\mu=0$ and computations imaginary values of the chemical potential are two most popular approaches to tackle sign problem in finite-density lattice QCD. The methods obviously related. In particular, coefficients often reconstructed from data obtained $\mu$. context Bielefeld-Parma collaboration, we have been generating which fed our multi-point Padé analysis QCD phase diagram. We report on studies different techniques compute $\mu=0$.
Abstract In the last three decades, numerical stochastic perturbation theory (NSPT) has proven to be an excellent tool for calculating perturbative expansions in theories such as Lattice QCD, which standard, diagrammatic is known cumbersome. Despite significant success of this method and improvements made recent years, NSPT apparently cannot successfully implemented low-dimensional models due emergence huge statistical fluctuations: order gets higher, signal noise ratio simply not good...
The appearance of large, none-Gaussian cumulants the baryon number distribution is commonly discussed as a signal for QCD critical point. We review status Taylor expansion cumulant ratios fluctuations along freeze-out line and also compare results with corresponding proton measured by STAR Collaboration at RHIC. To further constrain location possible point we discuss poles in complex plane. Here use not only coefficients obtained zero chemical potential but perform calculations pressure...