Publications associées à Non-Hermitian time evolution: From static to parametric instability

Emergent non-Hermitian localization phenomena in the synthetic space of zero-dimensional bosonic systems

Phase transitions in non-Hermitian systems are at the focus of cutting edge theoretical and experimental research. On the one hand, parity-time- (PT-) and anti-PT-symmetric physics have gained ever-growing interest, due to the existence of non-Hermitian sp ...

AMER PHYSICAL SOC2023

Dynamically crossing diabolic points while encircling exceptional curves: A programmable symmetric-asymmetric multimode switch

Fabrizio Minganti

Nontrivial spectral properties of non-Hermitian systems can lead to intriguing effects with no counterparts in Hermitian systems. For instance, in a two-mode photonic system, by dynamically winding around an exceptional point (EP) a controlled asymmetric-s ...

Nature Portfolio2023

Einstein's quantum elevator: Hermitization of non-Hermitian Hamiltonians via a generalized vielbein formalism

Fabrizio Minganti

The formalism for non-Hermitian quantum systems sometimes blurs the underlying physics. We present a systematic study of the vielbeinlike formalism which transforms the Hilbert space bundles of non-Hermitian systems into the conventional ones, rendering th ...

AMER PHYSICAL SOC2022

turboMagnon - A code for the simulation of spin-wave spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory

Iurii Timrov

We introduce turboMagnon, an implementation of the Liouville-Lanczos approach to linearized time-dependent density-functional theory, designed to simulate spin-wave spectra in solid-state materials. The code is based on the noncollinear spin-polarized fram ...

ELSEVIER2022

Strong second-harmonic generation from Au-Al heterodimers

Olivier Martin, Gabriel David Bernasconi, Jérémy Butet

Second-harmonic generation (SHG) is investigated from three kinds of lithographically fabricated plasmonic systems: Al monomers, Au monomers and Au-Al heterodimers with nanogaps of 20 nm. Spectrally integrated SHG intensities and the linear optical respons ...

2019

Less Is More: Enhancement of Second-Harmonic Generation from Metasurfaces by Reduced Nanoparticle Density

Olivier Martin, Jérémy Butet

We investigate optical second-harmonic generation (SHG) from metasurfaces where noncentrosymmetric V-shaped gold nanoparticles are ordered into regular array configurations. In contrast to expectations, a substantial enhancement of the SHG signal is observ ...

2018

Vibrational modes of Q-balls

Andrey Shkerin

We study linear perturbations of classically stable Q-balls in theories admitting analytic solutions. Although the corresponding boundary value problem is non-Hermitian, the analysis of perturbations can also be performed analytically in certain regimes. W ...

American Physical Society2018

Multiplicity Of Solutions For Linear Partial Differential Equations Using (Generalized) Energy Operators

Jean-Philippe Lucien Montillet

Families of energy operators and generalized energy operators have recently been introduced in the definition of the solutions of linear Partial Differential Equations (PDEs) with a particular application to the wave equation [ 15]. To do so, the author ha ...

Int Center Scientific Research & Studies2017

On sums of eigenvalues of elliptic operators on manifolds

Joachim Stubbe

We use the averaged variational principle introduced in a recent article on graph spectra [10] to obtain upper bounds for sums of eigenvalues of several partial differential operators of interest in geometric analysis, which are analogues of Kroger's bound ...

European Mathematical Soc2017

The Hamiltonian of the harmonic oscillator with an attractive delta '-interaction centred at the origin as approximated by the one with a triple of attractive delta-interactions

Fabio Rinaldi

In this note we provide an alternative way of defining the self-adjoint Hamiltonian of the harmonic oscillator perturbed by an attractive delta'-interaction, of strength beta, centred at 0 (the bottom of the confining parabolic potential), that was rigorou ...

Iop Publishing Ltd2016

Direct Comparison of Second Harmonic Generation and Two-Photon Photoluminescence from Single Connected Gold Nanodimers

Olivier Martin, Jérémy Butet

In this article we compare the two-photon photoluminescence and second harmonic generation from single connected gold nanodimers. Analyzing the particle size-dependent nonlinear optical spectra and performing excitation polarization resolved measurements u ...

American Chemical Society2016

Fano-resonant aluminum and gold nanostructures created with a tunable, up-scalable process

Olivier Martin, Benjamin Gallinet

An up-scalable approach for creating Fano-resonant nanostructures on large surfaces at visible wavelengths is demonstrated. The use of processes suitable for high throughput fabrication and the choice of aluminum as a cost-efficient plasmonic material ensu ...

Royal Society of Chemistry2015

Enhancement of Second Harmonic Signal in Nanofabricated Cones

Aleksandra Radenovic, Anna Fontcuberta i Morral, Martin Heiss, Fabrizia Dutto, Andrea Lovera, Oriol López Sánchez

Geometrical effects in optical nanostructures on nanoscale can lead to interesting phenomena such as inhibition of spontaneous emission,(1,2) high-reflecting omnidirectional mirrors, structures that exhibit low-loss-waveguiding,(3) and light confinement.(4 ...

2013

Developing luminescent Brownian probes for near-field investigations of the intracellular environment

Flavio Maurizio Mor

Life sciences have a constantly growing need for novel methodological approaches suitable to investigate the intracellular environment with increased temporal and spatial resolutions. Recently, optical near-field probes, such as laser-irradiated pointed me ...

EPFL2013

Global dynamics above the ground state energy for the one-dimensional NLKG equation

Joachim Krieger

In this paperwe obtain a global characterization of the dynamics of even solutions to the one-dimensional nonlinear Klein–Gordon (NLKG) equation on the line with focusing nonlinearity |u|p−1u, p > 5, provided their energy exceeds that of the ground state o ...

Springer Verlag2012

Trace Identities For Commutators, With Applications To The Distribution Of Eigenvalues

Joachim Stubbe

We prove trace identities for commutators of operators, which are used to derive sum rules and sharp universal bounds for the eigenvalues of periodic Schrodinger operators and Schrodinger operators on immersed manifolds. In particular, we prove bounds on t ...

2011

Controlling and utilizing optical forces at the nanoscale with plasmonic antennas

Olivier Martin, Andrea Lovera

Plasmonic dipole antennas are powerful optical devices for many applications since they combine a high field enhancement with outstanding tunability of their resonance frequency. The field enhancement, which is mainly localized inside the nanogap between b ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2011

Universal Bounds And Semiclassical Estimates For Eigenvalues Of Abstract Schrodinger Operators

Joachim Stubbe

We prove trace inequalities for a self-adjoint operator on an abstract Hilbert space, which extend those known previously for Laplacians and Schrodinger operators, freeing them from restrictive assumptions on the nature of the spectrum and allowing operato ...

2010

Parametric Resonance in Time-Dependent Networks of Hopf Oscillators

Max-Olivier Hongler, Julio Rodriguez

We study a collection of limit cycle oscillators with different frequencies interacting via networks. With static networks, our specific class of models produces a frequency learning mechanism leading the collection of oscillators to ultimately adopt a sin ...

2010

Solving surface plasmon resonances and near field in metallic nanostructures: Green's matrix method and its applications

Olivier Martin

With the development of nanotechnology, many new optical phenomena in nanoscale have been demonstrated. Through the coupling of optical waves and collective oscillations of free electrons in metallic nanostructures, surface plasmon polaritons can be excite ...

2010