Publications associées à Modèle sigma non linéaire

Role of stochastic noise and generalization error in the time propagation of neural-network quantum states

Neural-network quantum states (NQS) have been shown to be a suitable variational ansatz to simulate out-of-equilibrium dynamics in two-dimensional systems using timedependent variational Monte Carlo (t-VMC). In particular, stable and accurate time propagat ...

SCIPOST FOUNDATION2022

Small-angle neutron scattering study of mesoscale magnetic disordering and skyrmion phase suppression in the frustrated chiral magnet Co6.75Zn6.75Mn6.51

Henrik Moodysson Rønnow, Jonathan White

Co-Zn-Mn chiral cubic magnets display versatile magnetic skyrmion phases, including equilibrium phases stable far above and far below room temperature, and the facile creation of robust far-from-equilibrium skyrmion states. In this system, compositional di ...

INT UNION CRYSTALLOGRAPHY2022

Towards bootstrapping RG flows: sine-Gordon in AdS

João Miguel Augusto Penedones Fernandes

The boundary correlation functions for a Quantum Field Theory (QFT) in an Anti-de Sitter (AdS) background can stay conformally covariant even if the bulk theory undergoes a renormalization group (RG) flow. Studying such correlation functions with the numer ...

Springer Nature2021

Continuous dissipative phase transitions with or without symmetry breaking

Fabrizio Minganti

The paradigm of second-order phase transitions (PTs) induced by spontaneous symmetry breaking (SSB) in thermal and quantum systems is a pillar of modern physics that has been fruitfully applied to out-of-equilibrium open quantum systems. Dissipative phase ...

IOP Publishing Ltd2021

Simultaneous autoregressive models for spatial extremes

Emeric Rolland Georges Thibaud

Motivated by the widespread use of large gridded data sets in the atmospheric sciences, we propose a new model for extremes of areal data that is inspired by the simultaneous autoregressive (SAR) model in classical spatial statistics. Our extreme SAR model ...

WILEY2020

Bootstrapping massive quantum field theories

Denis Karateev, João Miguel Augusto Penedones Fernandes

We propose a new non-perturbative method for studying UV complete unitary quantum field theories (QFTs) with a mass gap in general number of spacetime dimensions. The method relies on unitarity formulated as positive semi-definiteness of the matrix of inne ...

Springer Nature2020

Asymptotic Freedom and Large Spin Antiferromagnetic Chains

Frédéric Mila, Samuel Gozel

Building on the mapping of large-S spin chains onto the O(3) nonlinear sigma model with coupling constant 2/S, and on general properties of that model (asymptotic freedom, implying that perturbation theory is valid at high energy, and Elitzur's conjecture ...

2019

Quantum phase transitions beyond Landau-Ginzburg theory in one-dimensional space revisited

Christopher Marc Mudry

The phase diagram of the quantum spin-1/2 antiferromagnetic J(1)-J(2) XXZ chain was obtained by Haldane using bosonization techniques [Haldane, Phys. Rev. B 25, 4925 (1982); 26, 5257 (1982)]. It supports three distinct phases for 0

2019

R-current three-point functions in 4d N=1 superconformal theories

Andrea Manenti, Alessandro Vichi

In 4d N = 1 superconformal field theories (SCFTs) the R-symmetry current, the stress-energy tensor, and the supersymmetry currents are grouped into a single object, the Ferrara-Zumino multiplet. In this work we study the most general form of three-point fu ...

Springer Nature2018

Renormalization of Horava gravity

Sergey Sibiryakov, Diego Blas Temino, Mario Herrero Valea

We prove perturbative renormalizability of projectable Horava gravity. The key element of the argument is the choice of a gauge which ensures the correct anisotropic scaling of the propagators and their uniform falloff at large frequencies and momenta. Thi ...

American Physical Society2016

Spontaneous dimerization, critical lines, and short-range correlations in a frustrated spin-1 chain

Frédéric Mila, Natalia Chepiga

We report on a detailed investigation of the spin-1 J1−J2−J3 Heisenberg model, a frustrated model with nearest-neighbor coupling J1, next-nearest neighbor coupling J2, and a three-site interaction J3[(Si−1⋅Si)(Si⋅Si+1)+H.c.] previously studied in [Phys. Re ...

2016

Prediction of phase ambiguity resolution based on signal intensity and geometry

Jan Skaloud

The goal of this contribution was to develop a reliable quality indicator reflecting the potential success of differential carrier phase ambiguity resolution for kinematic Global Positioning System (GPS). The indicator must be operable without any communic ...

Springer Verlag2015

A mean field model of dynamic and post-dynamic recrystallization predicting kinetics, grain size and flow stress

Roland Logé, Ke Huang

A physically-based two-site mean field model has been developed to describe the microstructural evolution due to recrystallization during and after deformation. The model has been applied to predict the recrystallized fraction, recrystallized grain size, a ...

Elsevier2015

Impact of axions on confinement in three and two dimensions

In this paper we discuss well-known three- and two-dimensional models with confinement, namely, the Polyakov compact electrodynamics in 3D and two-dimensional CP(N-1) sigma model, and reveal changes in the confining regimes of these models upon adding the ...

American Physical Society2015

Ultraviolet completion without symmetry restoration

Solomon G Shamsuddin Osman Endlich

We show that it is not possible to UV complete certain low-energy effective theories with spontaneously broken spacetime symmetries by embedding them into linear sigma models, that is, by adding "radial" modes and restoring the broken symmetries. When such ...

American Physical Society2014

Multipass forging of Inconel 718 in the delta-Supersolvus domain: assessing and modeling microstructure evolution

Roland Logé

This work is focused on the evolution of the microstructure of Inconel 718 during multi-pass forging processes. During the forming process, the material is subjected to several physical phenomena such as work-hardening, recovery, recrystallization and grai ...

E D P Sciences2014

Resting-State Functional Connectivity Emerges from Structurally and Dynamically Shaped Slow Linear Fluctuations

Patric Hagmann

Brain fluctuations at rest are not random but are structured in spatial patterns of correlated activity across different brain areas. The question of how resting-state functional connectivity (FC) emerges from the brain's anatomical connections has motivat ...

Society for Neuroscience2013

Wavelet-Based Reconstruction for Magnetic Resonance Imaging

Matthieu Guerquin-Kern

Magnetic resonance imaging (MRI) scanners produce raw measurements that are unfit to direct interpretation, unless an algorithmic step, called reconstruction, is introduced. Up to the last decade, this reconstruction was performed by algorithms of moderate ...

EPFL2012

On the effect of resonances in composite Higgs phenomenology

Riccardo Rattazzi, Duccio Pappadopulo, Roberto Contino

We consider a generic composite Higgs model based on the coset SO(5)= SO(4) and study its phenomenology beyond the leading low-energy effective lagrangian approximation. Our basic goal is to introduce in a controllable and simple way the lowest-lying, poss ...

Springer Nature2011

Metastable supersymmetry breaking in N=2 non-linear sigma-models

Claudio Scrucca, Jean-Claude Jacot

We perform a general study of the issue of metastability for supersymmetry-breaking vacua in theories with N=1 and N=2 global supersymmetry. This problem turns out to capture all the important qualitative features of the corresponding question in theories ...

Elsevier2010