Publications related to Universality (dynamical systems)

Critical properties of the quantum Ashkin-Teller chain with chiral perturbations

We investigate the nature of the phase transitions in the quantum Ashkin-Teller chain in the presence of chiral perturbations. We locate the Lifshitz line separating a region of direct chiral transitions from the region where the transition is through an i ...

Amer Physical Soc2023

Level crossings and chiral transitions in transverse-field Ising models of adatom and Rydberg chains

Ivo Aguiar Maceira

This thesis is motivated by recent experiments on systems described by extensions of the one-dimensional transverse-field Ising (TFI) model where (1) finite-size properties of Ising-ordered phases -- specifically, ground state level crossings -- were obser ...

EPFL2022

Microscopic interplay of temperature and disorder of a one-dimensional elastic interface

Elisabeth Agoritsas, Thierry Giamarchi

Elastic interfaces display scale-invariant geometrical fluctuations at sufficiently large lengthscales. Their asymptotic static roughness then follows a power-law behavior, whose associated exponent provides a robust signature of the universality class to ...

2022

Field-dependent roughness of moving domain walls in a Pt/Co/Pt magnetic thin film

Elisabeth Agoritsas

The creep motion of domain walls driven by external fields in magnetic thin films is described by universal features related to the underlying depinning transition. One key parameter in this description is the roughness exponent characterizing the growth o ...

2021

Lifshitz point at commensurate melting of chains of Rydberg atoms

Frédéric Mila, Natalia Chepiga

The recent investigation of chains of Rydberg atoms has brought back the problem of commensurateincommensurate transitions into the focus of current research. In two-dimensional classical systems or in one-dimensional quantum systems, the commensurate melt ...

2021

A numerical study of the statistics of roughness parameters for fluctuating interfaces

Elisabeth Agoritsas

Self-affine rough interfaces are ubiquitous in experimental systems, and display characteristic scaling properties as a signature of the nature of disorder in their supporting medium, i.e. of the statistical features of its heterogeneities. Different metho ...

2021

Unified analysis of topological defects in 2D systems of active and passive disks

Ignacio Pagonabarraga Mora, Pasquale Digregorio

We provide a comprehensive quantitative analysis of localized and extended topological defects in the steady state of 2D passive and active repulsive Brownian disk systems. We show that, both in and out-of-equilibrium, the passage from the solid to the hex ...

ROYAL SOC CHEMISTRY2021

Infinitesimal asphericity changes the universality of the jamming transition

Matthieu Wyart, Carolina Brito Carvalho dos Santos

The jamming transition of non-spherical particles is fundamentally different from the spherical case. Non-spherical particles are hypostatic at their jamming points, while isostaticity is ensured in the case of the jamming of spherical particles. This stru ...

IOP PUBLISHING LTD2020

Universality of jamming of nonspherical particles

Matthieu Wyart, Carolina Brito Carvalho dos Santos

Amorphous packings of nonspherical particles such as ellipsoids and spherocylinders are known to be hypostatic: The number of mechanical contacts between particles is smaller than the number of degrees of freedom, thus violating Maxwell's mechanical stabil ...

National Academy of Sciences2018

Robustness of Classifiers to Universal Perturbations: A Geometric Perspective

Pascal Frossard, Seyed Mohsen Moosavi Dezfooli, Alhussein Fawzi

Deep networks have recently been shown to be vulnerable to universal perturbations: there exist very small image-agnostic perturbations that cause most natural images to be misclassified by such classifiers. In this paper, we provide a quantitative analysi ...

2018

Dimerization and exotic criticality in spin-S chains

Natalia Chepiga

In this thesis we have studied the emergence of spontaneously dimerized phases in frustrated spin-S chains, with emphasis on the nature of the critical lines between the dimerized and non-dimerized phases. The main numerical method used in this thesis is t ...

EPFL2017

Coherent generation of symmetry-forbidden phonons by light-induced electron-phonon interactions in magnetite

Oleg Yazyev, Fabrizio Carbone, Frank van Mourik, Christopher Alexander Arrell, Edoardo Baldini, Andreas Helmut Christian Mann, Simone Borroni

Symmetry breaking across phase transitions often causes changes in selection rules and emergence of optical modes which can be detected via spectroscopic techniques or generated coherently in pump-probe experiments. In second-order or weakly first-order tr ...

Amer Physical Soc2017

Dimensional Reduction in Quantum Dipolar Antiferromagnets

Henrik Moodysson Rønnow, Martin Mansson, Peter Babkevich, Ivan Kovacevic

We report ac susceptibility, specific heat, and neutron scattering measurements on a dipolar-coupled antiferromagnet LiYbF4. For the thermal transition, the order-parameter critical exponent is found to be 0.20(1) and the specific-heat critical exponent -0 ...

2016

Exact diagonalization of HeisenbergSU(N)chains in the fully symmetric and antisymmetric representations

Frédéric Mila, Pierre Marcel Nataf

Motivated by recent experimental progress in the context of ultracold multicolor fermionic atoms in optical lattices, we have developed a method to exactly diagonalize the Heisenberg SU(N) Hamiltonian with several particles per site living in a fully symme ...

2016

Avalanches in dry and saturated disordered media at fracture

Jean-François Molinari, Enrico Milanese, Okan Yilmaz

This paper analyzes fracturing in inhomogeneous media under dry and fully saturated conditions. We adopt a central force model with continuous damage to study avalanche behavior in a two-dimensional truss lattice undergoing dilation. Multiple fractures can ...

Amer Physical Soc2016

The role of fluctuations in ecological patterns and processes

Andrea Giometto

Fluctuations are ubiquitous in nature and are relevant for nearly every ecological process. The main sources of fluctuations in population abundances are demographic and environmental stochasticity, whose effect on local population dynamics, metapopulation ...

EPFL2015

Importance of XY anisotropy in Sr2IrO4 revealed by magnetic critical scattering experiments

Henrik Moodysson Rønnow

The magnetic critical scattering in Sr2IrO4 has been characterized using x-ray resonant magnetic scattering (XRMS) both below and above the three-dimensional antiferromagnetic ordering temperature T-N. The order parameter critical exponent below TN is foun ...

2015

An intercomparison of subgrid models for large-eddy simulation of katabatic flows

Fernando Porté Agel, Craig Matthew Smith

We present an intercomparison of three subgrid-scale (SGS) models for large-eddy simulation (LES) of katabatic flows. The SGS closures we study include the Smagorinsky formulation, a scale-invariant dynamic model, and a scale-dependent dynamic model. Downs ...

Wiley-Blackwell2014

Capacity Scaling of Cognitive Networks: Beyond Interference-Limited Communication

Michael Christoph Gastpar

The capacity scaling laws of two overlaid networks are investigated, which are located in the same area sharing the same wireless resources with different priorities. The primary network can be regarded as an existing communication system operated in a lic ...

Institute of Electrical and Electronics Engineers2014

Universal scaling of plasmon coupling in metal nanostructures: Checking the validity for higher plasmonic modes using second harmonic generation

Olivier Martin, Pierre-François Marie Brevet, Jérémy Butet

The universal scaling of plasmon coupling in metallic nanostructures is now a well-established feature. However, if the interaction between dipolar plasmon modes has been intensively studied, this is not the case of the coupling between higher order ones. ...

Amer Physical Soc2013