Publications associées à Théorie de la perturbation (mécanique quantique)

Non-normal forms

In this thesis, we propose to formally derive amplitude equations governing the weakly nonlinear evolution of non-normal dynamical systems, when they respond to harmonic or stochastic forcing, or to an initial condition. This approach reconciles the non-mo ...

EPFL2024

An Asymmetric Perturbation Signal for Enhanced Perturbation Injection Capabilities of a Grid-Connected Converter

Drazen Dujic, Andrea Cervone, Jules Christian Georges Macé

Impedance estimation is an important tool for grid- converter interaction evaluation. Using existing grid-connected converters for perturbation injection enables grid impedance estimation during operation without additional hardware (namely dedicated pertu ...

2024

Hierarchy of quasisymmetries and degeneracies in the CoSi family of chiral crystal materials

Philip Johannes Walter Moll, Chunyu Guo, Yi-Chiang Sun

In materials, certain approximated symmetry operations can exist in a lower-order approximation of the effective model but are good enough to influence the physical responses of the system, and these approximated symmetries were recently dubbed "quasisymme ...

AMER PHYSICAL SOC2023

Noncollinear DFT plus U and Hubbard parameters with fully relativistic ultrasoft pseudopotentials

Nicola Marzari, Luca Binci

The magnetic, noncollinear parametrization of Dudarev's DFT + U method is generalized to fully relativistic ultrasoft pseudopotentials. We present the definition of the DFT + U total energy functional and the calculation of forces and stresses in the case ...

Amer Physical Soc2023

Magnon-phonon interactions enhance the gap at the Dirac point in the spin-wave spectra of CrI3 two-dimensional magnets

Iurii Timrov

Recent neutron-diffraction experiments in honeycomb CrI3 quasi-2D ferromagnets have evinced the existence of a gap at the Dirac point in their spin-wave spectra. The existence of this gap has been attributed to strong in-plane Dzyaloshinskii-Moriya or Kita ...

2023

Momentum-resolved spin-conserving two-triplon bound state and continuum in a cuprate ladder

Henrik Moodysson Rønnow, Thorsten Schmitt, Vladimir N. Strocov, Yi Tseng

Studying multi-particle elementary excitations has provided unique access to understand collective many-body phenomena in correlated electronic materials, paving the way towards constructing microscopic models. In this work, we perform O K-edge resonant in ...

NATURE PORTFOLIO2023

Measurement of differential cross sections for the production of a Z boson in association with jets in proton-proton collisions at √s=13 TeV

Matthias Finger, Konstantin Androsov, Qian Wang, Jan Steggemann, Yiming Li, Varun Sharma, Xin Chen, Arvind Shah, Rakesh Chawla, Jian Wang, João Miguel das Neves Duarte, Tagir Aushev, Matthias Wolf, Yi Zhang, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Leonardo Cristella, Siyuan Wang, Jessica Prisciandaro, Peter Hansen, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Davide Di Croce, Kun Shi, Wei Shi, Guido Andreassi, Abhisek Datta, Wei Sun, Jian Zhao, Thomas Berger, Federica Legger, Bandeep Singh, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Many-body physics with strongly interacting fermions coupled to light

Victor Youri Helson

This thesis reports on the realization of the first experiments conducted with superfluid, strongly interacting Fermi gases of 6Li coupled to the light field of an optical cavity. In the scope of existing ultracold atomic platforms, this is the first time ...

EPFL2023

Linear scattering theory of short-pulse reflectometry

Stefano Coda, Stephan Brunner, Oleg Krutkin

The linear scattering theory of short pulse reflectometry is presented. An expression for the scattering signal is obtained by applying the perturbation theory approach for solving the Helmholtz equation. Based on these analytical results, a method for mea ...

2023

Development of strategies to improve 1H resolution in NMR of solids at 100 kHz magic-angle spinning

Bruno Simões de Almeida

In solid-state NMR, homonuclear dipolar couplings contribute greatly to the broadening of 1H spectral line shapes. Even at the fastest magic-angle spinning rates (MAS) available today [100-150kHz], the linewidths still extend over several hundred Hertz, li ...

EPFL2023

Measurement of the t(t)over-bar charge asymmetry in events with highly Lorentz-boosted in collisions at √s=13 TeV

Matthias Finger, Konstantin Androsov, Qian Wang, Jan Steggemann, Anna Mascellani, Yiming Li, Varun Sharma, Xin Chen, Rakesh Chawla, Matteo Galli, Jian Wang, João Miguel das Neves Duarte, Tagir Aushev, Matthias Wolf, Yi Zhang, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Leonardo Cristella, Siyuan Wang, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Sun Hee Kim, Davide Di Croce, Kun Shi, Wei Shi, Abhisek Datta, Jian Zhao, Federica Legger, Gabriele Grosso, Ji Hyun Kim, Donghyun Kim, Zheng Wang, Sanjeev Kumar, , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Learning ground states of gapped quantum Hamiltonians with Kernel Methods

Giuseppe Carleo, Riccardo Rossi, Clemens Giuliani, Filippo Vicentini

Neural network approaches to approximate the ground state of quantum hamiltonians require the numerical solution of a highly nonlinear optimization problem. We introduce a statistical learning approach that makes the optimization trivial by using kernel me ...

Verein Forderung Open Access Publizierens Quantenwissenschaf2023

Universality of loop corrected soft theorems in 4d

Biswajit Sahoo

In [1], logarithmic correction to subleading soft photon and soft graviton theorems have been derived in four spacetime dimensions from the ratio of IR-finite S-matrices. This has been achieved after factoring out IR-divergent components from the tradition ...

Springer Nature2023

Center-aware Adversarial Augmentation for Single Domain Generalization

Mathieu Salzmann, Zhiye Wang

Domain generalization (DG) aims to learn a model from multiple training (i.e., source) domains that can generalize well to the unseen test (i.e., target) data coming from a different distribution. Single domain generalization (SingleDG) has recently emerge ...

IEEE COMPUTER SOC2023

A weakly nonlinear amplitude equation approach to the bypass transition in the two-dimensional Lamb–Oseen vortex

François Gallaire, Yves-Marie François Ducimetière

We analytically derive an amplitude equation for the weakly nonlinear evolution of the linearly most amplified response of a non-normal dynamical system. The development generalizes the method proposed in Ducimetière et al. (J. Fluid Mech., vol. 947, 2022, ...

Cambridge University Press2023

Advancing Computational Chemistry with Stochastic and Artificial Intelligence Approaches

Justin Villard

Computational chemistry aims to simulate reactions and molecular properties at the atomic scale, advancing the design of novel compounds and materials with economic, environmental, and societal implications. However, the field relies on approximate quantum ...

EPFL2023

Adaptive Fingers Coordination for Robust Grasp and In-Hand Manipulation Under Disturbances and Unknown Dynamics

Aude Billard, Farshad Khadivar

We present a control framework for achieving a robust object grasp and manipulation in hand. In-hand manipulation remains a demanding task as the object is never stable and task success relies on carefully synchronizing the fingers' dynamics. Indeed, finge ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Singular quadratic eigenvalue problems: linearization and weak condition numbers

Daniel Kressner, Ivana Sain Glibic

The numerical solution of singular eigenvalue problems is complicated by the fact that small perturbations of the coefficients may have an arbitrarily bad effect on eigenvalue accuracy. However, it has been known for a long time that such perturbations are ...

SPRINGER2023

Thermal critical points from competing singlet formations in fully frustrated bilayer antiferromagnets

Frédéric Mila, Antoine Yves Dimitri Fache

We examine the ground-state phase diagram and thermal phase transitions in a plaquettized fully frustrated bilayer spin-1/2 Heisenberg model. Based on a combined analysis from sign-problem free quantum Monte Carlo simulations, perturbation theory, and free ...

AMER PHYSICAL SOC2022

Two-dimensional Hubbard model at finite temperature: Weak, strong, and long correlation regimes

Riccardo Rossi

We investigate the momentum-resolved spin and charge susceptibilities, as well as the chemical potential and double occupancy in the two-dimensional Hubbard model as functions of doping, temperature, and interaction strength. Through these quantities, we i ...

AMER PHYSICAL SOC2022