Article
Optics
Liang Mao, Yajiang Hao, Lei Pan
Summary: In this paper, the non-Hermitian skin effect (NHSE) is extended from noninteracting systems to interacting many-body systems by studying an exactly solvable non-Hermitian model, the Lieb-Liniger Bose gas with imaginary vector potential. The NHSE is characterized quantitatively through solving the Bethe ansatz equations and calculating the model's density profiles and momentum distributions. It is found that the NHSE is enhanced for bound-state solutions on the attractive side, while it shows a nonmonotonic behavior for the scattering state. This work provides an example of NHSE in exactly solvable many-body systems and suggests its extension to other non-Hermitian many-body systems, particularly integrable models.
Article
Physics, Multidisciplinary
J. Settino, N. Lo Gullo, F. Plastina, A. Minguzzi
Summary: The study introduces a method to accurately evaluate the spectral function of a gas of one-dimensional bosons, showing three main singularity lines in the spectral function under lattice confinement, with the Lieb-II mode exhibiting divergence, providing a way to probe this mode in experiments with ultracold atoms.
PHYSICAL REVIEW LETTERS
(2021)
Article
Quantum Science & Technology
Thomas Fogarty, Thomas Busch
Summary: This study demonstrates that a quantum Otto cycle involving a transition of an ultracold gas between superfluid and insulating phases can outperform single particle cycles. Utilizing the energy gap and the interplay between lattice forces and particle distribution can lead to a many-body cooperative effect. Introducing an approximate shortcut to adiabaticity for efficient cycling around a critical point can help mitigate unwanted non-equilibrium dynamics.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Applied
Yajiang Hao, Yiwang Liu, Xiangguo Yin
Summary: In this study, the correlation properties of the ground state of Tonks-Girardeau gases are investigated in momentum space. The ground state wavefunction in coordinate space is obtained using the Bose-Fermi mapping method based on the wavefunction of spin-polarized fermions. Fourier transformation is then applied to obtain the ground state wavefunction, pair correlation, and reduced one-body density matrix in momentum space. The correlations in momentum space exhibit larger values only in small momentum regions and vanish in most other regions. Additionally, the lowest natural orbital and occupation distribution in momentum space are obtained.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2023)
Article
Optics
Glen J. Kissel
Summary: Anderson localization simulations in one-dimensional disordered optical systems often focus on the localization length or its inverse, with less emphasis on the calculation of the density of states. This paper modifies a technique originally used for calculating the integrated density of states for one-dimensional disordered crystals to be applicable to randomly layered optical media. The density of states can then be easily obtained through differentiation. The algorithm is demonstrated on one-dimensional quarter-wave stack and non-quarter-wave stack models with disordered layer thicknesses.
Article
Optics
Jean Claude Garreau, Veronique Zehnle
Summary: This work introduces a simple technique to generate various dispersion relations in a modulated tilted lattice. Important examples, including the Dirac, Bogoliubov, and Landau dispersion relations, are illustrated. It is shown that adding a slow temporal phase shift to the lattice modulation allows for the reconstruction of the dispersion relation from dynamical quantities. Furthermore, the technique is generalized to higher dimensions, generating graphene-like Dirac points and flat bands in two dimensions.
Article
Physics, Multidisciplinary
Nick Sauerwein, Francesca Orsi, Philipp Uhrich, Soumik Bandyopadhyay, Francesco Mattiotti, Tigrane Cantat-Moltrecht, Guido Pupillo, Philipp Hauke, Jean-Philippe Brantut
Summary: Random spin models are important for understanding disorder and complex many-body systems. Two all-to-all interacting, disordered models have been realized using a cavity quantum electrodynamics platform. These models have a wide range of applications in various disciplines. By adjusting the detuning between atom resonance and cavity mode, an all-to-all interacting, disordered spin system can be achieved. This research provides insight into the competition between interactions and disorder in these models and opens up possibilities for designing arbitrary spin Hamiltonians.
Article
Physics, Multidisciplinary
Bjoern Schrinski, Anders S. Sorensen
Summary: Photons strongly coupled to material systems provide a new approach to realize nonlinear optics at the level of individual photons and study the dynamics of non-equilibrium quantum many-body systems. By using a simple physical polariton-picture, we can analytically describe the dynamics of photons coupled to a one-dimensional array of two-level atoms, including polariton scattering inside the medium and reflections of polaritons from the array's edge. We show that inelastic collisions, observed in small systems, also occur in infinite systems due to the existence of multiple bands in the dispersion relation. The developed theory serves as an effective field theory for studying nonlinear optics and many-body dynamics.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
T. P. L. Ung, X. Quelin, J. Laverdant, R. Fulcrand, J-P Hermier, S. Buil
Summary: This paper focuses on the optical properties of disordered hole arrays etched in a gold thin film, showing that increasing the disorder leads to broadened absorption in the far field, indicating energy localization induced by the disorder and its dependence on the amount of disorder and excitation wavelength.
Article
Optics
Seunghwa Oh, Jungmin Kim, Xianji Piao, Seulong Kim, Kihong Kim, Sunkyu Yu, Namkyoo Park
Summary: The effect of deep subwavelength disorder in one-dimensional dichromic multilayer films on optical transmission, localization length, and the Goos-Fanchen shift around the critical angle is analyzed. The study emphasizes the role of deep subwavelength structures in disorder-induced transmission enhancement and suggests the inverse design of such structures for targeted order metrics or abnormal optical responses.
Article
Physics, Applied
Peng-Xiang Xie, Zong-Qiang Sheng, Ze-Xin Huang, Ping-Hu, Hong-Wei Wu
Summary: In this study, we designed an acoustic waveguide by utilizing small periodic rigid plates to support spoof acoustic surface waves, which can be controlled by modifying the waveguide widths. By constructing acoustic waveguide arrays with parabolic refractive-index distributions, sound can be focused on deep-subwavelength focal points, surpassing the diffraction limit. Theoretical predictions and experimental results both demonstrate the tunability of the focusing point and lateral shifts of the spoof acoustic surface waves, providing a feasible pathway for achieving compact and tunable sound focusing and super-resolution acoustic imaging on a subwavelength scale.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Enguo Guan, Gang Wang, Xi-Wen Guan, Xiaoming Cai
Summary: We study the localization properties and mobility edges of a generalized spinful Aubry-Andre-Harper (AAH) model, which is derived from the two-dimensional Hofstadter model with a non-Abelian SU(2) gauge potential. The model exhibits different localization properties depending on the ratio of the quasiperiod to the lattice size. Tuning the non-Abelian gauge potential leads to an unconventional reentrant localization phase transition. In the semiclassical limit, the model with the non-Abelian gauge potential has more mobility edges than the model with the Abelian gauge potential. We analytically obtain exact expressions of the mobility edges and localization phase diagrams using a semiclassical method.
Article
Multidisciplinary Sciences
Benedikt Kloss, Jad C. Halimeh, Achilleas Lazarides, Yevgeny Bar Lev
Summary: Kloss et al theoretically and numerically establish the absence of many-body localization in a broad class of spin models that respect certain symmetries.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Yu He, Shiqi Xia, Dimitris G. Angelakis, Daohong Song, Zhigang Chen, Daniel Leykam
Summary: In this study, we explore the use of persistent homology to characterize phases in a generalized Aubry-Andre-Harper model. The persistent entropy and mean squared lifetime obtained using persistent homology behave similarly to conventional measures and can distinguish different phases, including ordered and disordered regimes. This approach can be applied to both energy eigenstates and wave packet propagation dynamics.
Article
Physics, Mathematical
Wenwen Jian, Jia Shi, Xiaoping Yuan
Summary: In this study, the Cartan estimate for meromorphic functions is utilized to establish Anderson localization for a specific type of long-range operators with singular potentials.
JOURNAL OF MATHEMATICAL PHYSICS
(2021)
Article
Multidisciplinary Sciences
Shiqi Xia, Dimitrios Kaltsas, Daohong Song, Ioannis Komis, Jingjun Xu, Alexander Szameit, Hrvoje Buljan, Konstantinos G. Makris, Zhigang Chen
Summary: The study established a nonlinear non-Hermitian topological platform for active tuning of PT symmetry and topological states, revealing the interaction between sensitivity close to exceptional points and the robustness of non-Hermitian topological states. The research provides opportunities for unconventional light manipulation and device applications through single-channel control of global PT symmetry and topology via local nonlinearity.
Article
Optics
Xiuying Liu, Frane Lunic, Daohong Song, Zhixuan Dai, Shiqi Xia, Liqin Tang, Jingjun Xu, Zhigang Chen, Hrvoje Buljan
Summary: Pseudospins arising from valley degrees of freedom in photonic structures have become a powerful tool for manipulating the flow of light, allowing for wavepacket self-rotation induced by Berry phase and resulting in Zitterbewegung oscillations. The frequency of Zitterbewegung is proportional to the gap size, while the helicity of self-rotation is valley-dependent, correlated with the Berry curvature. These findings provide new insights into the Zitterbewegung phenomenon from a topological perspective and have potential applications in other platforms such as 2D Dirac materials and ultracold atoms.
LASER & PHOTONICS REVIEWS
(2021)
Article
Optics
Zhichan Hu, Domenico Bongiovanni, Dario Jukic, Ema Jajtic, Shiqi Xia, Daohong Song, Jingjun Xu, Roberto Morandotti, Hrvoje Buljan, Zhigang Chen
Summary: This study uncovered the interplay of nonlinearity, higher-order topology, and BICs in a photonic platform, where topological corner states that are also BICs were observed. The authors further demonstrated the nonlinear coupling of these states with edge modes under the action of self-focusing and defocusing nonlinearities. Theoretical calculations showed that a topological BIC can be actively tuned by nonlinearity in such a photonic HOTI, with potential applications in emerging topology-driven devices.
LIGHT-SCIENCE & APPLICATIONS
(2021)
News Item
Physics, Multidisciplinary
Hrvoje Buljan, Dario Jukic, Zhigang Chen
Article
Physics, Multidisciplinary
Domenico Bongiovanni, Dario Jukic, Zhichan Hu, Frane Lunic, Yi Hu, Daohong Song, Roberto Morandotti, Zhigang Chen, Hrvoje Buljan
Summary: In the evolving Su-Schrieffer-Heeger lattices made of interacting soliton arrays, dynamical topological phase transitions occur entirely driven by nonlinearity. The transitions involve a periodic shift from topologically trivial-to-nontrivial phases, with crossovers from topologically nontrivial-to-trivial regimes. The signature of the phase transition is the closing and reopening of the gap, where extended states become localized topological edge states through decoupling from the lattice bulk.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Ziteng Wang, Xiangdong Wang, Zhichan Hu, Domenico Bongiovanni, Dario Jukic, Liqin Tang, Daohong Song, Roberto Morandotti, Zhigang Chen, Hrvoje Buljan
Summary: Some topological boundary states are protected by sub-symmetry, even if the full symmetry and topological invariant are destroyed. By introducing a weaker sub-symmetry requirement, researchers find that the nature of boundary state protection is more complex than previously believed. Experimental demonstrations in photonic lattices show the sub-symmetry protection of topological states and the resolution of debates on the higher-order topological nature of corner states in breathing kagome lattices. These findings have implications beyond photonics and can be applied to explore symmetry-protected topological phases in different physical contexts.
Article
Optics
Yahui Zhang, Domenico Bongiovanni, Ziteng Wang, Xiangdong Wang, Shiqi Xia, Zhichan Hu, Daohong Song, Dario Jukic, Jingjun Xu, Roberto Morandotti, Hrvoje Buljan, Zhigang Chen
Summary: The orbital degrees of freedom play a pivotal role in understanding fundamental phenomena in solid-state materials as well as exotic quantum states of matter. High orbitals in higher-order topological insulators (HOTIs) have not been realized, but p-orbital corner states have been demonstrated in a photonic HOTI, unveiling their underlying topological invariant and symmetry protection.
Article
Physics, Multidisciplinary
Ioannis Komis, Dimitrios Kaltsas, Shiqi Xia, Hrvoje Buljan, Zhigang Chen, Konstantinos G. Makris
Summary: This article studies the properties of non-Hermitian topological systems under different perturbations. By studying the non-Hermitian Su-Schrieffer-Heeger lattice, it is found that the topological modes around the underlying third-order exceptional point are robust against chiral perturbations but sensitive to diagonal perturbations.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Bruno Klajn, Silvije Domazet, Dario Jukic, Hrvoje Buljan
Summary: An exactly solvable model for synthetic anyons carrying non-Abelian flux is proposed in this study. The system, which corresponds to a two-dimensional electron gas in a magnetic field with specific spin interaction, displays twofold degeneracy in the ground state subspace. Perturbing the system with identical solenoids carrying a non-Abelian gauge potential reveals the dynamics of ground state behaving as anyons with non-Abelian flux. This system serves as a middle ground between ordinary Abelian anyons and fully non-Abelian anyons.
Article
Optics
Karlo Lelas, Ozana Celan, David Prelogovic, Hrvoje Buljan, Dario Jukic
Summary: In this study, we investigated the modulation instability of systems obeying the nonlinear Schrödinger equation under the influence of an external homogeneous synthetic magnetic field. The choice of gauge used to describe the magnetic field affects the stability regions in momentum space and the time evolution in real space. Despite appearances, the gauge invariance is not actually broken, as evolving the system from identical initial conditions in different gauges is equivalent to suddenly turning on the synthetic magnetic field at t = 0, resulting in different effects on the wave packet.