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Exceptional points (EPs), i.e. branch point singularities of non-Hermitian Hamiltonians, are ubiquitous in optics. So far, the signatures of EPs have been mostly studied assuming classical light. In the passive parity-time ($\mathcal{PT}$)…

Quantum Physics · Physics 2018-12-11 Stefano Longhi

In this work, we consider a two level $P\sigma_{z}$ pseudo-Hermitian system in contact with a thermal bath to study various thermodynamic properties. The system is realized in terms of infinitely many invariant subspaces. We find explicit…

Quantum Physics · Physics 2025-03-25 Gargi Das , Bhabani Prasad Mandal

We demonstrate that the non-Hermitian parity-time (PT) symmetric interfaces formed between amplifying and lossy crystals support dissipationless edge states. These PT edge states exhibit gapless spectra in the complex band structure…

Mesoscale and Nanoscale Physics · Physics 2018-10-24 Xiang Ni , Daria Smirnova , Alexander Poddubny , Daniel Leykam , Yidong Chong , Alexander B. Khanikaev

We study the pseudo-Hermitian systems with general spin-coupling point interactions and give a systematic description of the corresponding boundary conditions for PT-symmetric systems. The corresponding integrability for both bosonic and…

Quantum Physics · Physics 2009-11-11 Shao-Ming Fei

Non-Hermitian physics has unlocked a wealth of unconventional wave phenomena beyond the reach of Hermitian systems, with exceptional points (EPs) driving enhanced sensitivity, nonreciprocal transport, and topological behavior unique to…

We present the observation of diabolic points in Hermitian and non-Hermitian electronics dimers. The condition of unbreakable Parity-time symmetry is established for both PT-symmetric ZRC and RLC dimers. We show how appears non-Hermitian…

Applied Physics · Physics 2020-05-25 Stéphane Boris Tabeu , Fernande Fotsa-Ngaffo , Aurélien Kenfack-Jiotsa

The spin-boson model is a paradigm for studying decoherence, relaxation, entanglement and other effects that arise in a quantum system coupled to environmental degrees of freedom. At zero temperature, a localization-delocalization phase…

Quantum Physics · Physics 2015-01-22 Yao Yao , Nengji Zhou , Javier Prior , Yang Zhao

The effect of non-Hermiticity in band topology has sparked many discussions on non-Hermitian topological physics. It has long been known that non-Hermitian Hamiltonians can exhibit real energy spectra under the condition of parity-time…

Mesoscale and Nanoscale Physics · Physics 2024-03-20 Yang Long , Haoran Xue , Baile Zhang

Non-Hermitian systems, going beyond conventional Hermitian systems, have brought in intriguing concepts such as exceptional points and complex spectral topology as well as exotic phenomena such as non-Hermitian skin effects (NHSEs).…

Quantum Physics · Physics 2024-09-23 Li-Wei Wang , Jian-Hua Jiang

Dynamically encircling an exceptional point (EP) in parity-time (PT) symmetric systems shows an interesting chiral dynamics, leading to asymmetric mode switching in which the output modes are different when the encircling direction is…

Optics · Physics 2019-10-16 Xu-Lin Zhang , Tianshu Jiang , Hong-Bo Sun , C. T. Chan

We analyze the behavior of a non-Hermitian opened one-dimensional quantum system with $\mathcal{PT}$ symmetry. This system is built by a dimer, with balanced gains and losses described by a parameter $\gamma$. By varying $\gamma$ the system…

Quantum Physics · Physics 2024-04-11 J. Colín-Gálvez , E. Castaño , G. Báez , V. Domínguez-Rocha

The heightened sensitivity observed in non-Hermitian systems at exceptional points (EPs) has garnered significant attention. Typical EP sensor implementations rely on precise measurements of spectra and importantly, for real time sensing…

Optics · Physics 2023-10-18 Parul Sharma , Brijesh Kumar , Nihar Ranjan Sahoo , Anshuman Kumar

Exceptional points (EPs) are exotic degeneracies of non-Hermitian systems, where the eigenvalues and the corresponding eigenvectors simultaneously coalesce in parameter space, and these degeneracies are sensitive to tiny perturbations on…

Non-Hermitian systems with parity-time symmetry have been developed rapidly and hold great promise for future applications. Unlike most existing works considering the symmetry of the free energy terms (e.g., gain-loss system), in this…

Quantum Physics · Physics 2017-11-21 Wenlin Li , Chong Li , Heshan Song

Motivated by the recent growing interest in the field of $\mathcal{P}\mathcal{T}$-symmetric Hamiltonian systems we theoretically study the emergency of singularities called Exceptional Points ($\textit{EP}$s) in the eigenspectrum of…

Quantum Physics · Physics 2023-08-15 Grigory A. Starkov , Mikhail V. Fistul , Ilya M. Eremin

Non-Hermitian systems have been at the center of intense research for over a decade, partly due to their nontrivial energy topology formed by intersecting Riemann manifolds with branch points known as exceptional points (EPs). This spectral…

Higher-order exceptional points (EPs) in non-Hermitian systems have attracted great interest due to their advantages in sensitive enhancement and distinct topological features. However, realization of such EPs is still challenged because…

Quantum Physics · Physics 2022-09-29 Wei Xiong , Zhuanxia Li , Guo-Qiang Zhang , Mingfeng Wang , Hai-Chao Li , Xiao-Qing Luo , Jianjiao Chen

We study the dynamics of correlations in a paradigmatic setup to observe $\mathcal{PT}$-symmetric physics: a pair of coupled oscillators, one subject to a gain one to a loss. Starting from a coherent state, quantum correlations (QCs) are…

Non-Hermitian models with real eigenenergies are highly desirable for their stability. Yet, most of the currently known ones are constrained by symmetries such as PT-symmetry, which is incompatible with realizing some of the most exotic…

Mesoscale and Nanoscale Physics · Physics 2022-07-13 Boxue Zhang , Qingya Li , Xiao Zhang , Ching Hua Lee

Non-Hermitian systems exhibit many peculiar dynamic behaviors which never showed up in Hermitian systems. The existence of spectral singularity (SS) for a non-Hermitian scattering center provides a lasing mechanism in the context of quantum…

Quantum Physics · Physics 2019-04-11 K. L. Zhang , P. Wang , Z. Song