122 citations · 303 across the 13 of their papers we have counts for
13 papers
Direct experimental observation of total absorption and loss compensation using sound waves with complex frequencies
Anis Maddi, Gaelle Poignand, Vassos Achilleos +2
In this study, we experimentally investigate the application of a transient signal with complex frequencies to the absorption and transmission of sound waves. Indeed, the emission…
A nonreciprocal and tunable active acoustic scatterer
Anis Maddi, Gaelle Poignand, Vassos Achilleos +2
A passive loudspeaker mounted in a duct acts as a reciprocal scatterer for plane waves impinging on either of its sides. However, the reciprocity can be broken by means of an asymm…
Robustness of perfect transmission resonances to asymmetric perturbation
Ioannis Kiorpelidis, Panayotis Kalozoumis, Georgios Theocharis +3
We investigate the impact of asymmetric perturbations on the perfect transmission resonances (PTRs) of one-dimensional finite periodic systems. With no perturbations, the scatterin…
Transient amplification in stable Floquet media
Ioannis Kiorpelidis, Fotios K. Diakonos, Georgios Theocharis +1
The Mathieu equation occurs naturally in the description of vibrations or in the propagation of waves in media with time-periodic refractive index. It is known to lead to exponenti…
Existence and characterization of edge states in an acoustic trimer Su-Schrieffer-Heeger model
I. Ioannou Sougleridis, A. Anastasiadis, O. Richoux +4
We report on a direct mapping of acoustic slender waveguides to the one dimensional trimer Su- Schrieffer-Heeger model, with neither chiral nor mirror symmetry. Importantly, we can…
Emergent non-Hermitian models
Lumen Eek, Anouar Moustaj, Malte Röntgen +3
The Hatano-Nelson and the non-Hermitian Su-Schrieffer-Heeger model are paradigmatic examples of non-Hermitian systems that host non-trivial boundary phenomena. In this work, we use…
Higher-order mode filtering by a resistive layer
Svetlana Kuznetsova, Yves Auregan, Vincent Pagneux
A method of higher-order modes filtering in an air-filled waveguide using a resistive layer is proposed. An analogue of Cremer's criterion is discussed and used to obtain the optim…
Exact analogue of the Hatano-Nelson model in 1D continuous nonreciprocal systems
Anis Maddi, Yves Auregan, Guillaume Penelet +2
We propose a general framework that enables the exact mapping of continuous nonreciprocal 1D periodic systems to the Hatano-Nelson (HN) model. Our approach, based on the two-port t…
Topologically invisible defects in chiral mirror lattices
Antonin Coutant, Li-Yang Zheng, Vassos Achilleos +3
One of the hallmark of topological insulators is having conductivity properties that are unaffected by the possible presence of defects. In this work, we go beyond backscattering i…
Hidden symmetries in acoustic wave systems
Malte Röntgen, Christian V. Morfonios, Peter Schmelcher +1
Mirror symmetry of a wave system imposes corresponding even or odd parity on its eigenmodes. For a discrete system, eigenmode parity on a specific subset of sites may also originat…
Finite size effects on topological interface states in one-dimensional scattering systems
P. A. Kalozoumis, G. Theocharis, V. Achilleos +3
One-dimensional topological edge modes are usually studied considering the interface between two different semi infinite periodic crystals (PCs) with inverted band structure around…
Scattering by finite periodic -symmetric structures
V. Achilleos, Y. Aurégan, V. Pagneux
In this work, we study the transmission properties of one dimensional finite periodic systems with -symmetry. A simple closed form expression is obtained for the tota…
Non-Hermitian Acoustic Metamaterials: the role of Exceptional Points in sound absorption
V. Achilleos, G. Theocharis, O. Richoux +1
Effective non-Hermitian Hamiltonians are obtained to describe coherent perfect absorbing and lasing boundary conditions. PT -symmetry of the Hamiltonians enables to design configur…