Concept

Perturbation theory

Related publications (290)

Many-body perturbation theory calculations using the yambo code

Antimo Marrazzo, Gianluca Prandini, Andrea Ferretti

yambo is an open source project aimed at studying excited state properties of condensed matter systems from first principles using many-body methods. As input, yambo requires ground state electronic structure data as computed by density functional theory c ...

IOP PUBLISHING LTD2019

On the Averaged Green’s Function of an Elliptic Equation with Random Coefficients

Marius Christopher Lemm

We consider a divergence-form elliptic difference operator on the lattice Zd, with a coefficient matrix that is an i.i.d. perturbation of the identity matrix. Recently, Bourgain introduced novel techniques from harmonic analysis to prove the convergence of ...

2019

Phonon Lifetimes Throughout the Brillouin Zone at Elevated Temperatures from Experiment and ab initio

Albert Johann Glensk

We obtain phonon lifetimes in aluminium by inelastic neutron scattering experiments, by ab initio molecular dynamics, and by perturbation theory. At elevated temperatures significant discrepancies are found between experiment and perturbation theory, which ...

2019

Coupled-mode theory for stationary and nonstationary resonant sound propagation

Romain Christophe Rémy Fleury, Theodoros Koutserimpas

In this paper, we present a complete analytical derivation of the equations used for stationary and nonstationary wave systems regarding resonant sound transmission and reflection described by the phenomenological coupled-mode theory. We calculate the prop ...

2019

Koopmans Meets Bethe-Salpeter: Excitonic Optical Spectra without GW

Nicola Marzari, Nicola Colonna, Paolo Umari

The Bethe Salpeter equation (BSE) can be applied to compute from first-principles optical spectra that include the effects of screened electron hole interactions. As input, BSE calculations require single-particle states, quasiparticle energy levels, and t ...

AMER CHEMICAL SOC2019

The epsilon expansion meets semiclassics

Riccardo Rattazzi, Alexander Monin, Gil Badel, Gabriel Francisco Cuomo

We study the scaling dimension Delta(phi n) of the operator phi(n) where phi is the fundamental complex field of the U(1) model at the Wilson-Fisher fixed point in d = 4 - epsilon. Even for a perturbatively small fixed point coupling lambda*, standard pert ...

Springer2019

At the Intersection of Microbiota and Circadian Clock: Are Sexual Dimorphism and Growth Hormones the Missing Link to Pathology? Circadian Clock and Microbiota: Potential Egffect on Growth Hormone and Sexual Development

Frédéric Bruno Martin Gachon, Benjamin Dieter Weger

Reciprocal interactions between the host circadian clock and the microbiota are evidenced by recent literature. Interestingly, dysregulation of either the circadian clock or microbiota is associated with common human pathologies such as obesity, type 2 dia ...

WILEY2019

Geometry of adversarial robustness of deep networks: methods and applications

Seyed Mohsen Moosavi Dezfooli

We are witnessing a rise in the popularity of using artificial neural networks in many fields of science and technology. Deep neural networks in particular have shown impressive classification performance on a number of challenging benchmarks, generally in ...

EPFL2019

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

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

Universal Adversarial Attacks on Text Classifiers

Pascal Frossard, Seyed Mohsen Moosavi Dezfooli, Melika Behjati

Despite the vast success neural networks have achieved in different application domains, they have been proven to be vulnerable to adversarial perturbations (small changes in the input), which lead them to produce the wrong output. In this paper, we propos ...

IEEE2019

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