activity
20222026
most citedThe Non-Hermitian Skin Effect With Three-Dimensional Long-Range Coupling

3 citations · 9 across the 23 of their papers we have counts for

collaborators

26 papers

math.AP2026

Frequency-dependent capacitance matrix formulation for Fabry--Pérot resonances. Part II: One-dimensional periodic media

Habib Ammari, Bowen Li, Ping Liu +1

We study Bloch resonances of one-dimensional periodic systems of high-contrast resonators beyond the subwavelength regime. An exact transfer-matrix formulation identifies the limit…

math.SP2026

Topological properties and a multiplicative Bloch-Floquet-Zak transform for scattering by self-similar or fractal media

Habib Ammari, Yat Tin Chow, Fuqun Han

We develop the first rigorous topological framework for an auxiliary boundary-integral model motivated by physical scaling identities for wave scattering from self-similar or fract…

math-ph2026

Long-range interactions and Anderson localisation for one-dimensional high-contrast resonator chain

Habib Ammari, Silvo Barandun, Jiayu Qiu +1

Spectral and transport properties of high-contrast resonator systems can be described in the subwavelength regime in terms of the so-called capacitance operator. In this paper, we…

math.AP2026

Frequency-dependent capacitance matrix formulation for Fabry-Perot resonances in two and three dimensional systems

Habib Ammari, Bowen Li, Ping Liu +2

We study scattering resonances of finite and infinite periodic two- and three-dimensional systems of high-contrast resonators beyond the subwavelength regime. At each fixed admissi…

math.AP2026

Frequency-dependent capacitance matrix formulation for Fabry-Pérot resonances. Part I: One-dimensional finite systems

Habib Ammari, Bowen Li, Ping Liu +1

We study scattering resonances of finite one-dimensional systems of high-contrast resonators beyond the subwavelength regime. Introducing a novel tridiagonal frequency-dependent ca…

math-ph2026

Non-Hermitian Fabry-Pérot Resonances

Habib Ammari, Erik Orvehed Hiltunen, Bowen Li +4

We characterise non-Hermitian Fabry-Pérot resonances in high-contrast resonator systems and study the properties of their associated resonant modes from continuous differential mod…

math-ph2026

A Real-Space Formulation of the Zak Phase via Weyl m-Functions

Habib Ammari, Clemens Thalhammer

We establish a new, real-space formula for the Zak phase for one dimensional periodic Jacobi operators in terms of the Weyl -function that does not rely on Floquet-Bloch theor…

math-ph2026

A Tight-binding Approach for Computing Subwavelength Guided Modes in Crystals with Line Defects

Habib Ammari, Erik Orvehed Hiltunen, Ping Liu +2

In this paper, we develop a framework for computing subwavelength guided modes in high-contrast periodic media with line defects, based on a tight-binding approximation. The physic…

physics.optics2025

Topological interface modes in aperiodic subwavelength resonator chains

Habib Ammari, Jiayu Qiu, Alexander Uhlmann

We consider interface modes in block disordered subwavelength resonator chains in one dimension. Based on the capacitance operator formulation, which provides a first-order approxi…

math-ph2025

Uniform Hyperbolicity, Bandgaps and Edge Modes in Aperiodic Systems of Subwavelength Resonators

Habib Ammari, Clemens Thalhammer, Alexander Uhlmann

We aim to characterise the spectral distributions of bi-infinite, semi-infinite, and finite aperiodic one-dimensional arrays of subwavelength resonators, constructed by sampling fr…

math-ph2025

Competing edge and bulk localisation in non-reciprocal disordered systems

Habib Ammari, Silvio Barandun, Clemens Thalhammer +1

We investigate the competing mechanisms of localisation in one-dimensional block disordered subwavelength resonator systems subject to non-reciprocal damping, induced by an imagina…

math-ph2025

Universal estimates for the density of states for aperiodic block subwavelength resonator systems

Habib Ammari, Silvio Barandun, Bryn Davies +2

We consider the spectral properties of aperiodic block subwavelength resonator systems in one dimension, with a primary focus on the density of states. We prove that for random blo…

cond-mat.dis-nn2024★ 1 cited

Subwavelength Localisation in Disordered Systems

Habib Ammari, Silvio Barandun, Alexander Uhlmann

We elucidate the different mechanisms of wave localisation in disordered finite systems of subwavelength resonators, where the disorder is in the spatial arrangement of the resonat…

physics.optics2024★ 1 cited

Effective Medium Theory for Time-modulated Subwavelength Resonators

Habib Ammari, Jinghao Cao, Erik Orvehed Hiltunen +1

This paper provides a general framework for deriving effective material properties of one-dimensional, time-modulated systems of subwavelength resonators. It applies to subwaveleng…

math-ph2024

Truncated Floquet-Bloch transform for computing the spectral properties of large finite systems of resonators

Habib Ammari, Silvio Barandun, Alexander Uhlmann

The truncated Floquet-Bloch transform can be used to characterise the spectral properties of finite periodic and aperiodic large systems of resonators. This paper aims to provide f…

math-ph2024

Applications of Chebyshev polynomials and Toeplitz theory to topological metamaterials

Habib Ammari, Silvio Barandun, Ping Liu

We survey the use of Chebyshev polynomials and Toeplitz theory for studying topological metamaterials. We consider both Hermitian and non-Hermitian systems of subwavelength resonat…

math.AP2024

Space-Time Wave Localisation in Systems of Subwavelength Resonators

Habib Ammari, Erik Orvehed Hiltunen, Liora Rueff

In this paper we study the dynamics of metamaterials composed of high-contrast subwavelength resonators and show the existence of localised modes in such a setting. A crucial assum…

math-ph2024★ 1 cited

Generalised Brillouin Zone for Non-Reciprocal Systems

Habib Ammari, Silvio Barandun, Ping Liu +1

Recently, it has been observed that the Floquet-Bloch transform with real quasiperiodicities fails to capture the spectral properties of non-reciprocal systems. The aim of this pap…

physics.optics2024★ 1 cited

Tunable Localisation in Parity-Time-Symmetric Resonator Arrays with Imaginary Gauge Potentials

Habib Ammari, Silvio Barandun, Ping Liu +1

The aim of this paper is to illustrate both analytically and numerically the interplay of two fundamentally distinct non-Hermitian mechanisms in a deep subwavelength regime. Consid…

cond-mat.mes-hall2024

A two-scale effective model for defect-induced localization transitions in non-Hermitian systems

Bryn Davies, Silvio Barandun, Erik Orvehed Hiltunen +2

We illuminate the fundamental mechanism responsible for the transition between the non-Hermitian skin effect and defect-induced localization in the bulk. We study a Hamiltonian wit…

math-ph2024★ 1 cited

Spectra and pseudo-spectra of tridiagonal -Toeplitz matrices and the topological origin of the non-Hermitian skin effect

Habib Ammari, Silvio Barandun, Yannick De Bruijn +2

We establish new results on the spectra and pseudo-spectra of tridiagonal -Toeplitz operators and matrices. In particular, we prove the connection between the winding number of…

math-ph2024

Scattering from time-modulated subwavelength resonators

Habib Ammari, Jinghao Cao, Erik Orvehed Hiltunen +1

We consider wave scattering from a system of highly contrasting resonators with time-modulated material parameters. In this setting, the wave equation reduces to a system of couple…

math-ph2023

Exponentially localised interface eigenmodes in finite chains of resonators

Habib Ammari, Silvio Barandun, Bryn Davies +3

This paper studies wave localisation in chains of finitely many resonators. There is an extensive theory predicting the existence of localised modes induced by defects in infinitel…

math.AP2023★ 3 cited

The Non-Hermitian Skin Effect With Three-Dimensional Long-Range Coupling

Habib Ammari, Silvio Barandun, Jinghao Cao +3

We study the non-Hermitian skin effect in a three-dimensional system of finitely many subwavelength resonators with an imaginary gauge potential. We introduce a discrete approximat…