Concept

Circular symmetry

Publications associées (15)

Is motor asymmetry a predictor of non-motor outcomes in Parkinson’s disease?

The objective of this opinion paper is to highlight, based on recent studies, the importance of considering motor symptom (a)symmetry in the progression and management of non-motor symptoms in Parkinson’s disease.

Springer Science and Business Media LLC2026

Quantum vorticity: A not so effective field theory

We provide a comprehensive picture for the formulation of the perfect fluid in the modern effective field theory formalism at both the classical and quantum level. Due to the necessity of decomposing the hydrodynamical variables (\rho, p, u^\mu) into other internal degrees of freedom, the procedure is inherently not unique. We discuss and compare the different inequivalent formulations. These theories possess a peculiarity: the presence of an infinite dimensional symmetry implying a vanishing dispersion rel

Stichting SciPost2026

From Property Prediction to Long-Stride Dynamics: Accelerating Atomistic Simulation with Machine Learning

Atomic-scale simulations provide a computational method to probe the properties of molecules and materials. Their predictive power is highest when the interactions between atoms are obtained from electronic-structure theory, but the cost of these calculations limits the accessible system sizes, time scales, and statistical accuracy. Machine learning offers a way to overcome these limitations: expensive quantum-mechanical calculations can be replaced by much faster regression models trained on reference data

EPFL2026

On-Surface Synthesis of Porous Nitrogen-Doped Graphene Nanoribbons: Role of Substrate Orientation

Contributing to the design of functional graphene nanoribbons (GNRs) structures, we have synthesized porous and doped armchair graphene nanoribbons (N-GNRs) on Cu(111), Ag(100), and Ag(110) with atomic precision. The structural characterization and reaction step have been investigated using scanning tunneling microscopy. Despite pronounced differences in surface symmetry and chemical reactivity, the hierarchical polymerization of 2,7,11,16-tetrabromotetrabenzo[a,c,h,j]phenazine (TBTBP) through the on-surfac

Elsevier BV2026

The dark side of the forces: assessing non-conservative force models for atomistic machine learning

The use of machine learning to estimate the energy of a group of atoms, and the forces that drive them to more stable configurations, have revolutionized the fields of computational chemistry and materials discovery. In this domain, rigorous enforcement of symmetry and conservation laws has traditionally been considered essential. For this reason, interatomic forces are usually computed as the derivatives of the potential energy, ensuring energy conservation. Several recent works have questioned this physic

PMLR2025

The DELVE Quadruple Quasar Search. I. A Lensed Low-luminosity Active Galactic Nucleus

A quadruply lensed source, J125856.3-031944, has been discovered using the DELVE survey and Wide-field Infrared Survey Explorer W1-W2 colors. Follow-up direct imaging carried out with the Magellan Baade 6.5 m telescope is analyzed, as is spectroscopy from the 2.5 m Nordic Optical Telescope. The lensed image configuration is kite-like, with the major axis of the lensing galaxy along the symmetry axis of the kite, and with the faintest image at its tail. Redward of 6000 Å, the tail image is strongly blended w

2025

Cross-polarized and stable second harmonic generation from monocrystalline copper

Second-harmonic generation (SHG) is a powerful surface-specific probe for centrosymmetric materials, with broad relevance to energy and biological interfaces. Plasmonic nanomaterials have been extensively utilized to amplify this nonlinear response. Yet, material instability has constrained most studies to gold, despite the significance of plasmonic metals such as copper for catalysis. Here, we demonstrate stable and anisotropic SHG from monocrystalline copper, overcoming long-standing challenges associated

Walter de Gruyter GmbH2025

Supply-Demand Symmetry

We study what properties a liquidity surface (LS) must possess when the supply and demand of a given market are in equilibrium. To formalize this concept, we first analyze foreign exchange markets, where symmetry between the buy and sell sides just amounts to the invariance of market impact with respect to a change of base currency. We speak in this case of supply-demand symmetry, and call the corresponding LS symmetrical. We then extend the idea to general securities, applying similar change of numeraire a

SSRN2024

Graph Laplacians for Rotation Equivariant Convolutional Neural Networks

A fundamental problem in signal processing is to design computationally efficient algorithms to filter signals. In many applications, the signals to filter lie on a sphere. Meaningful examples of data of this kind are weather data on the Earth, or images of the sky. It is then important to design filtering algorithms that are computationally efficient and capable of exploiting the rotational symmetry of the problem. In these applications, given a continuous signal

f: \mathbb S^2 \rightarrow \mathbb R

on a

2019

Time reversal and symmetries of time correlation functions

Sara Bonella, Alessandro Coretti

The time reversal invariance of classical dynamics is reconsidered in this paper with specific focus on its consequences for time correlation functions and associated properties such as transport coefficients. We show that, under fairly common assumptions ...

Taylor & Francis2018

Investigation of the RF efficiency of Inductively Coupled Hydrogen Plasmas at 1MHz

Minh Quang Tran, Stefano Mattei

The power requirements of RF heated sources for negative hydrogen ions in fusion are substantial, which poses strong demands on the generators and components of the RF circuit. Consequently, an increase of the RF coupling efficiency would be highly benefic ...

Amer Inst Physics2017

Spectroscopic characterisation of H2 and D2 helicon plasmas generated by a resonant antenna for neutral beam applications in fusion

Basil Duval, Ivo Furno, Alan Howling, Alexander Karpushov, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Riccardo Agnello, Gennady Plyushchev, Kevin Henricus Annemarie Verhaegh, Claudio Marini

A new generation of neutral beam systems will be required in future fusion reactors, such as DEMO, able to deliver high power (up to 50 MW) with high (800 keV or higher) neutral energy. Only negative ion beams may be able to attain this performance, which ...

IOP Publishing Ltd2017

Center-stable manifold of the ground state in the energy space for the critical wave equation

We construct a center-stable manifold of the ground state solitons in the energy space for the critical wave equation without imposing any symmetry, as the dynamical threshold between scattering and blow-up, and also as a collection of solutions which stay close to the ground states. Up to energy slightly above the ground state, this completes the 9-set classication of the global dynamics in our previous paper [14]. We can also extend the manifold to arbitrary energy size by adding large radiation. The mani

Springer Verlag2015

Simulating the effect of fiber bridging and asymmetry on the fracture behavior of adhesively-bonded composite joints

Thomas Keller

The fracture behavior of adhesively-bonded pultruded double cantilever beam specimens is studied in this chapter. The crack propagates along paths away from the symmetry plane and is accompanied by fiber bridging. Finite element models are developed to quantify the effects of asymmetry and fiber bridging on the fracture energy. The virtual crack closure technique can be used for calculation of the fracture components at the crack tip and an exponential traction–separation cohesive law can be applied to simu

Elsevier2015

On the global structure of deformed Yang-Mills theory and QCD(adj) on R-3 x S-1

Spatial compactification on R(3)xS(L)(1), at small S-1-size L often leads to a calculable vacuum structure, where various "topological molecules" are responsible for confinement and the realization of the center and discrete chiral symmetries. Within this ...

Springer Nature2015

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