Publications associées à Self énergie

Physical and unphysical regimes of self-consistent many-body perturbation theory

In the standard framework of self-consistent many-body perturbation theory, the skeleton series for the self-energy is truncated at a finite order N and plugged into the Dyson equation, which is then solved for the propagator G(N). We consider two examples ...

Scipost Foundation2024

Topological photonic transport in disordered scattering networks

Zhechen Zhang

This Ph.D. thesis unveils the unique topological phenomena occurring in such networks, focusing on the intricate interplay between their Floquet topology, the presence of disorder, and their unitary scattering at microscopic and macroscopic scales. Using t ...

EPFL2024

Nonempirical semilocal density functionals for correcting the self-interaction of polaronic states

Alfredo Pasquarello, Stefano Falletta

Through the use of the piecewise-linearity condition of the total energy, we correct the self-interaction for the study of polarons by constructing nonempirical functionals at the semilocal level of theory. We consider two functionals, the gamma DFT and mu ...

Aip Publishing2024

Self-Interaction and Polarons in Density Functional Theory

Stefano Falletta

The electron self-interaction is a long-standing problem in density functional theory and is particularly critical in the description of polarons. Polarons are quasiparticles involving charge localization coupled with self-induced lattice distortions. Sinc ...

EPFL2023

Fermi energy determination for advanced smearing techniques

Nicola Marzari, Flaviano José Dos Santos

Smearing techniques are widely used in first-principles calculations of metallic and magnetic materials where they improve the accuracy of Brillouin-zone sampling and lessen the impact of level-crossing instabilities. Smearing introduces a fictitious elect ...

AMER PHYSICAL SOC2023

Many-Body Self-Interaction and Polarons

Alfredo Pasquarello, Stefano Falletta

We address the many-body self-interaction in relation to polarons in density functional theory. Our study provides (i) a unified theoretical framework encompassing many-body and one-body forms of self-interaction and (ii) an efficient semilocal scheme for ...

2022

Polarons free from many-body self-interaction in density functional theory

Alfredo Pasquarello, Stefano Falletta

We develop a unified theoretical framework encompassing one-body and many-body forms of self-interaction. We find an analytic expression for both the one-body and the many-body self-interaction energies, and quantitatively connect the two expressions throu ...

2022

Unraveling looping efficiency of stochastic Cosserat polymers

Raushan Singh, Giulio Corazza

Understanding looping probabilities, including the particular case of ring closure or cyclization, of fluctuating polymers (e.g., DNA) is important in many applications in molecular biology and chemistry. In a continuum limit the configuration of a polymer ...

AMER PHYSICAL SOC2022

Effect of collisions on non-adiabatic electron dynamics in ITG-driven microturbulence

Stephan Brunner, Justin Richard Ball

Non-adiabatic electron response leads to significant changes in ion temperature gradient (ITG) eigenmodes, leading, in particular, to fine-structures that are significantly extended along the magnetic field lines at corresponding mode rational surfaces (MR ...

2021

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

Self-interacting neutrinos: Solution to Hubble tension versus experimental constraints

Emmanuel Stamou

Exotic self-interactions among the Standard Model neutrinos have been proposed as a potential reason behind the tension in the expansion rate, H-0, of the universe inferred from different observations. We constrain this proposal using electroweak precision ...

American Physical Society2021

Quantum vibronic effects on the electronic properties of solid and molecular carbon

Michele Ceriotti, François Gygi, Han Yang

We study the effect of quantum vibronic coupling on the electronic properties of carbon allotropes, including molecules and solids, by combining path integral first principles molecular dynamics (FPMD) with a colored noise thermostat. In addition to avoidi ...

AMER PHYSICAL SOC2021

Interacting Dirac materials

Gabriel Aeppli

We investigate the extent to which the class of Dirac materials in two-dimensions provides general statements about the behavior of both fermionic and bosonic Dirac quasiparticles in the interacting regime. For both quasiparticle types, we find common feat ...

2020

Generalization of the Haldane conjecture to SU(n) chains

Frédéric Mila, Miklos Lajko

Recently, SU(3) chains in the symmetric and self-conjugate representations have been studied using field theory techniques. For certain representations, namely rank-psymmetric ones with pnot a multiple of 3, it was argued that the ground state exhibits gap ...

2020

Goldstone equivalence and high energy electroweak physics

Andrea Wulzer, Gabriel Francisco Cuomo, Luca Vecchi

The transition between the broken and unbroken phases of massive gauge theories, namely the rearrangement of longitudinal and Goldstone degrees of freedom that occurs at high energy, is not manifestly smooth in the standard formalism. The lack of smoothnes ...

2020

Studying the effect of non-adiabatic passing electron dynamics on microturbulence self-interaction in fusion plasmas using gyrokinetic simulations

Ajay Chandrarajan Jayalekshmi

Microturbulence driven by plasma instabilities is in most cases the dominant cause of heat and particle loss from the core of magnetic confinement fusion devices and therefore presents a major challenge in achieving burning plasma conditions. The role of p ...

EPFL2020

Koopmans-Compliant Functionals and Potentials and Their Application to the GW100 Test Set

Nicola Marzari, Nicola Colonna, Ngoc Linh Nguyen, Andrea Ferretti

Koopmans-compliant (KC) functionals have been shown to provide accurate spectral properties through a generalized condition of piecewise linearity of the total energy as a function of the fractional addition/removal of an electron to/from any orbital. We a ...

AMER CHEMICAL SOC2019

Advantageous nearsightedness of many-body perturbation theory contrasted with Kohn-Sham density functional theory

Christoph Leopold Talirz

For properties of interacting electron systems, Kohn-Sham (KS) theory is often favored over many-body perturbation theory (MBPT), owing to its low computational cost. However, the exact KS potential can be challenging to approximate, for example in the pre ...

AMER PHYSICAL SOC2019

Hidden and explicit quantum scale invariance

Sander Johannes Nicolaas Mooij, Mikhail Chapochnikov, Thibault Voumard

There exist renormalization schemes that explicitly preserve the scale invariance of a theory at the quantum level. Imposing a scale-invariant renormalization breaks renormalizability and induces new nontrivial operators in the theory. In this work, we stu ...

American Physical Society2019

Solving puzzles of spontaneously broken spacetime symmetries

Andrey Shkerin

We establish a classical analog of the Nambu-Goldstone theorem for spontaneous breaking of spacetime symmetries. It provides a counting rule for independent Nambu-Goldstone fields and states which of them are gapped. We demonstrate that only those symmetry ...

American Physical Society2018