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Exceptional points (EP) are non-Hermitian spectral degeneracies where both eigenvalues and their corresponding eigenvectors coalesce. Recently, EPs have attracted a lot of attention as a means to enhance the responsivity of sensors, via the…

Applied Physics · Physics 2022-02-22 Rodion Kononchuk , Jizhe Cai , Fred Ellis , Ramathasan Thevamaran , Tsampikos Kottos

We propose a novel scheme for enhancing the quality factor of coupled resonators optical waveguides (CROWs) when operating near a degenerate band edge (DBE). A DBE is a four-mode exceptional point of degeneracy (EPD) occurring when four…

We exploit the premises of exceptional points of degeneracy (EPDs) induced in linear time-periodic (LTP) systems to achieve extremely sensitive biosensors. The EPD is formed in a single LC resonator where the total capacitance is comprised…

The growing complexity of integrated photonics necessitates compact, low-power devices that transcend traditional, material-centric design approaches. In this study, we harness non-Hermitian physics to uncover novel properties of coupled…

Optics · Physics 2025-10-30 P. Chang , S. Ramezanpour , A. Helmy

We propose a new kind of physically realizable exceptional point degeneracies (EPDs) corresponding to synthetic reflectionless modes (SRM). These are solutions of an auxiliary wave operator that is defined in synthetic frequency dimensions…

Optics · Physics 2025-08-06 William Tuxbury , Lucas Fernandez-Alcazar , Tsampikos Kottos

Exceptional point degeneracies (EPD) of linear non-Hermitian systems have been recently utilized for hypersensitive sensing. This proposal exploits the sublinear response that the degenerate frequencies experience once the system is…

We show the physical realization and experimental demonstration of an exceptional point of 6th order degeneracy in a triple ladder (or three-way) microwave waveguide realized using three coupled microstrips on a grounded dielectric…

The interplay between coherent and dissipative dynamics required in various control protocols of quantum technology has motivated studies of open-system degeneracies, referred to as exceptional points (EPs). Here, we introduce a scheme for…

Quantum Physics · Physics 2023-08-23 Wallace S. Teixeira , Vasilii Vadimov , Timm Mörstedt , Suman Kundu , Mikko Möttönen

This study presents a novel three-way unequal filtering power divider/combiner, addressing challenges in unequal power distribution while incorporating filtering functions in communication systems. Wilkinson power divider (WPD) is the…

Systems and Control · Electrical Eng. & Systems 2025-04-08 Augustine O. Nwajana , Mosammat Rokaiya Akter , Muhammad Asfar Saeed

We investigate exceptional points of degeneracy (EPDs) in electromagnetic scattering of a sphere dimer from the electroquasistatic limit to the fully retarded regime. In the quasistatic limit, we prove that $\parity\trev$-symmetric…

Optics · Physics 2026-05-29 Emanuele Corsaro , Filippo Capolino , Carlo Forestiere

Electron Bernstein Waves (EBWs) are electrostatic waves than can propagate in overdense plasmas without density cutoff, making them suitable for high density plasma heating. Since EBWs cannot be directly launched from vacuum, mode…

Plasma Physics · Physics 2026-04-01 Chenxu Wang , Ryota Usui , Hiroaki Nakamura , Hideki Kawaguchi , Kubo Shin

An exceptional point of degeneracy (EPD) occurs when both the eigenvalues and the corresponding eigenvectors of a square matrix coincide and the matrix has a nontrivial Jordan block structure. It is not easy to achieve an EPD exactly. In…

Classical Physics · Physics 2023-12-13 Kasra Rouhi , Filippo Capolino , Alexander Figotin

It has been experimentally established that the occurrence of charge density waves is a common feature of various under-doped cuprate superconducting compounds. The observed states, which are often found in the form of bond density waves…

Strongly Correlated Electrons · Physics 2020-07-01 Hossein Dehghani , Zachary M. Raines , Victor M. Galitski , Mohammad Hafezi

We report a 1D planar optical waveguide with transverse distribution of inhomogeneous loss profile, which exhibits an exceptional point (EP). The waveguide hosts two leaky resonant modes; where the interaction between them in the vicinity…

Optics · Physics 2018-11-14 Arnab Laha , Abhijit Biswas , Somnath Ghosh

The past few years have witnessed growing interests in exceptional points (EPs) in various domains, including photonics, acoustics and electronics. However, EPs have mainly been realized based on the degeneracy of resonances of physical…

Optics · Physics 2021-09-20 Changqing Wang , William R. Sweeney , A. Douglas Stone , Lan Yang

We experimentally demonstrate for the first time the degenerate band edge (DBE) condition, namely the degeneracy of four Bloch modes, in loaded circular metallic waveguides. The four modes forming the DBE represent a degeneracy of fourth…

Exceptional points (EP) in non-Hermitian systems have been widely investigated due to their enhanced sensitivity in comparison to standard systems. In this letter, we report the observation of higher-order pseudo-Hermitian degeneracies in…

Applied Physics · Physics 2023-05-02 Ke Yin , Xianglin Hao , Yuangen Huang , Jianlong Zou , Xikui Ma , Tianyu Dong

We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that are mechanically coupled. The gain (loss) is controlled by driving the resonator with laser that is blue (red) detuned. We predict analytically…

Mesoscale and Nanoscale Physics · Physics 2019-02-18 P. Djorwe , Y. Pennec , B. Djafari-Rouhani

Exceptional points (EPs) are degeneracies in open wave systems where at least two energy levels and their corresponding eigenstates coalesce. We report evidence of the existence of EPs in 3D plasmonic nanostructures. The systems are…

Optics · Physics 2017-02-02 Ashok Kodigala , Thomas Lepetit , Boubacar Kanté

This paper aims to investigate electric dynamics and improve electric power generation of an isolated wave energy converter that uses a linear permanent magnet generator as the power take-off system, excited by regular or irregular waves.…

Applied Physics · Physics 2020-09-29 LiGuo Wang , MaoFeng Lin , Elisabetta Tedeschi , Jens Engström , Jan Isberg