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Related papers: Non-Hermitian Dirac cones with valley-dependent li…

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Non-Hermitian (NH) Dirac semimetals describe open gain--loss systems. Yet at charge neutrality, models featuring real spectrum often look Hermitian-like, with NH effects absorbed into renormalized band parameters. Here, we show that a…

Mesoscale and Nanoscale Physics · Physics 2026-05-19 Sergio Pino-Alarcón , Juan Pablo Esparza , Vladimir Juričić

The dynamical and topological properties of non-Hermitian systems have attracted great attention in recent years. In this work, we establish an intrinsic connection between two classes of intriguing phenomena -- topological phases and…

Quantum Physics · Physics 2021-06-18 Longwen Zhou , Qianqian Du

Due to their iconic linearly vanishing density of states near the zero-energy, half-filled two-dimensional Dirac materials in flat Euclidean and negatively-curved hyperbolic spaces exhibit dynamic mass generation only once a critical…

Strongly Correlated Electrons · Physics 2025-10-03 Christopher A. Leong , Bitan Roy

We theoretically study a tunneling effect in a two-dimensional Dirac semimetal with two Dirac points protected by non-symmorphic symmetries. The tunnel barrier can be arranged by a magnetic exchange potential which opens a gap at the Dirac…

Mesoscale and Nanoscale Physics · Physics 2017-03-08 Tetsuro Habe

Lorentz spacetime symmetry represents a unifying feature of the fundamental forces, typically manifest at sufficiently high energies, while in quantum materials it emerges in the deep low-energy regime. However, its fate in quantum…

Strongly Correlated Electrons · Physics 2024-05-30 Vladimir Juricic , Bitan Roy

Two-dimensional semimetals with tilted Dirac cones in the electronic band structure are shown to exhibit spatial separation of carriers belonging to different valleys under illumination. In stark contrast to gapped Dirac materials this…

Mesoscale and Nanoscale Physics · Physics 2023-11-08 A. Wild , E. Mariani , M. E. Portnoi

We investigate quantum dynamics of a quantum walker on a finite bipartite non-Hermitian lattice, in which the particle can leak out with certain rate whenever it visits one of the two sublattices. Quantum walker initially located on one of…

Quantum Physics · Physics 2021-05-13 Li Wang , Qing Liu , Yunbo Zhang

To simulate the dynamics of massless Dirac fermions in curved spacetimes with one, two, and three spatial dimensions we construct tight-binding Hamiltonians with spatially varying hoppings. These models represent tilted Weyl semimetals…

Mesoscale and Nanoscale Physics · Physics 2022-12-14 Viktor Könye , Corentin Morice , Dmitry Chernyavsky , Ali G. Moghaddam , Jeroen van den Brink , Jasper van Wezel

Non-Hermitian band descriptions capture how loss, gain, and environmental coupling reshape quantum matter, yet most experimental tests rely on wave-based or dynamical probes. Here we establish a new equilibrium route to exceptional physics…

Mesoscale and Nanoscale Physics · Physics 2026-04-16 Juan Pablo Esparza , Francisco J. Peña , Patricio Vargas , Vladimir Juričić

Non-Hermitian Hamiltonians are relevant to describe the features of a broad class of physical phenomena, ranging from photonics and atomic and molecular systems to nuclear physics and mesoscopic electronic systems. An important question…

Mesoscale and Nanoscale Physics · Physics 2021-04-21 Ygor Pará , Giandomenico Palumbo , Tommaso Macrì

Rarely noted paradoxes and their resolution lead to non-Hermitian behaviors due to boundary terms, even for closed systems and with real potentials. The role played by these non-Hermiticities on quantum mechanical uncertainty relations is…

General Physics · Physics 2021-10-05 K. Moulopoulos

The type-II Dirac cone is a special feature of the band structure, whose Fermi level is represented by a pair of crossing lines. It has been demonstrated that such a structure is useful for investigating topological edge solitons, and more…

Optics · Physics 2024-09-09 Qian Tang , Milivoj R. Belić , Hua Zhong , Meng Cao , Yongdong Li , Yiqi Zhang

We develop an effective quantum electrodynamics for non-Hermitian (NH) Dirac materials interacting with photons. These systems are described by nonspatial symmetry protected Lorentz invariant NH Dirac operators, featuring two velocity…

Strongly Correlated Electrons · Physics 2024-01-26 Sk Asrap Murshed , Bitan Roy

Two-dimensional Dirac semimetals with a single massless Dirac cone exhibit the parity anomaly. Usually, such a kind of anomalous topological semimetallic phase in real materials is unstable where any amount of disorder can drive it into a…

Mesoscale and Nanoscale Physics · Physics 2023-09-14 Zhen Ning , Xianyong Ding , Dong-Hui Xu , Rui Wang

We investigate localization-delocalization transition in one-dimensional non-Hermitian quasiperiodic lattices with exponential short-range hopping, which possess parity-time ($\mathcal{PT}$) symmetry. The localization transition induced by…

Disordered Systems and Neural Networks · Physics 2020-05-27 Yanxia Liu , Xiang-Ping Jiang , Junpeng Cao , Shu Chen

We study the localization transition in periodically driven one-dimensional non-Hermitian lattices where the piece-wise two-step drive is constituted by uniform coherent tunneling and incommensurate onsite gain and loss. We find that the…

Quantum Physics · Physics 2022-03-14 C. M. Dai , Yunbo Zhang , Xuexi Yi

Graphene on hexagonal boron nitride (hBN) can exhibit a topological phase via mutual crystallographic alignment. Recent measurements of nonlocal resistance ($R_{nl}$) near the secondary Dirac point (SDP) in ballistic graphene/hBN…

Mesoscale and Nanoscale Physics · Physics 2020-12-21 Yang Li , Mario Amado , Timo Hyart , Grzegorz P. Mazur , Jason W. A. Robinson

The spectral properties of a non-Hermitian quasi-1D lattice in two of the possible dimerization configurations are investigated. Specifically, it focuses on a non-Hermitian diamond chain that presents a zero-energy flat band. The flat band…

Mesoscale and Nanoscale Physics · Physics 2023-12-19 C. Martínez-Strasser , M. A. J. Herrera , A. García-Etxarri , G. Palumbo , F. K. Kunst , D. Bercioux

Non-Hermitian physics characterized by complex band spectra has established a new paradigm in condensed matter systems and metamaterials. Recently, non-Hermitian gain and nonreciprocity are deliberately introduced to valley manipulation,…

Materials Science · Physics 2025-10-27 Shunda Yin , Qiuyan Zhou , Yuxiang Xi , Weiyin Deng , Wei Chen , Jiuyang Lu , Manzhu Ke , Zhengyou Liu

We study theoretically two-dimensional single-crystalline sheets of semiconductors that form a honeycomb lattice with a period below 10 nm. These systems could combine the usual semiconductor properties with Dirac bands. Using atomistic…

Mesoscale and Nanoscale Physics · Physics 2015-02-19 E. Kalesaki , C. Delerue , C. Morais Smith , W. Beugeling , G. Allan , D. Vanmaekelbergh