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Photonics Research 2023年第10期11卷 I0011-I0021页

作者： JULIUS KULLIG DANIEL GROM SEBASTIAN KLEMBT jan wiersig Institut für Physik Otto-von-Guericke-Universität Magdeburg39106 MagdeburgGermany Technische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat Physikalisches Institut and Wilhelm-Conrad-Röntgen-Research Center for Complex Material SystemsAm HublandUniversity of Würzburg97070 WürzburgGermany

Exceptional points are degeneracies in the spectrum of non-Hermitian open systems where at least two eigenfrequencies and simultaneously the corresponding eigenstates of the Hamiltonian ***,the robust construction of higher-order exceptional points with more than two degenerate eigenfrequencies and eigenstates is challenging but yet worthwhile for *** this paper,we reconsider the formation of higher-order exceptional points through waveguide-coupled microring cavities and asymmetric *** this context,we demonstrate the influence of perturbations on the frequency splitting of the *** generate higher-order exceptional points in a simple and robust way,a mirror-induced asymmetric backscattering approach is *** addition to the exceptional-point enhanced sensing capabilities of such systems,also a cavity-selective sensitivity is achieved for particle *** results are motivated by an effective Hamiltonian description and verified by full numerical simulations of the dielectric structure.

关键词： structure exceptional splitting

Review of exceptional point-based sensors

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Photonics Research 2020年第9期8卷 1457-1467页

作者： jan wiersig Institut für Physik Otto-von-Guericke-Universität MagdeburgPostfach 4120D-39016 MagdeburgGermanyJAN

Exceptional points are spectral singularities in open quantum and wave systems that exhibit a strong spectral response to *** feature can be exploited for a new generation of *** paper explains the basic mechanism and comprehensively reviews the recent *** particular,it highlights the influence of classical noise and fundamental limitations due to quantum noise.

关键词： quantum exceptional spectral

Non-Hermitian degeneracies of internal–external mode pairs in dielectric microdisks

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Photonics Research 2019年第4期7卷 464-472页

作者： CHANG-HWAN YI JULIUS KULLIG MARTINA HENTSCHEL jan wiersig Institut für Physik Otto-von-Guericke-Universit?t Magdeburg Institut für Physik Technische Universit?t Ilmenau

Open quantum and wave systems can exhibit non-Hermitian degeneracies called exceptional points, where both the eigenvalues and the corresponding eigenstates coalesce. Previously, such exceptional points have been investigated in dielectric microcavities in terms of optical modes which are well confined inside the cavity. However,beside these so-called "internal modes" with a relatively high quality factor, there exists another kind of mode called "external modes," which have a large decay rate and almost zero intensity inside the cavity. In the present paper, we demonstrate the physical significance of the external modes via the occurrence of exceptional points of internal–external mode pairs for transverse electric polarization. Our numerical studies show that these exceptional points can be achieved by either a boundary deformation of the microdisk or by introducing absorption into a circular cavity.

关键词： electric optical wave can via Our be

Spontaneous T-symmetry breaking and exceptional points in cavity quantum electrodynamics systems

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Science Bulletin 2018年第17期63卷 1096-1100页

作者： Yu-Kun Lu Pai Peng Qi-Tao Cao Da Xu jan wiersig Qihuang Gong Yun-Feng Xiao State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter School of Physics Peking University Beijing 100871 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan 030006 China Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02139 USA Institut für Physik Otto-von-Guericke-Universitat Magdeburg Postfach 4120 D-39016 Magdeburg Germany

Spontaneous symmetry breaking has revolutionized the understanding in numerous fields of modern physics. Here, we theoretically demonstrate the spontaneous time-reversal symmetry breaking in a cavity quantum electrodynamics system in which an atomic ensemble interacts coherently with a single resonant cavity mode. The interacting system can be effectively described by two coupled oscillators with positive and negative mass, when the two-level atoms are prepared in their excited states. The occurrence of symmetry breaking is controlled by the atomic detuning and the coupling to the cavity mode,which naturally divides the parameter space into the symmetry broken and symmetry unbroken *** two phases are separated by a spectral singularity, a so-called exceptional point, where the eigenstates of the Hamiltonian coalesce. When encircling the singularity in the parameter space, the quasiadiabatic dynamics shows chiral mode switching which enables topological manipulation of quantum states.

关键词：对称系统 Hamiltonian 现代物理模式控制空间划分原子振荡器