11 papers
Anomalous Collision of Exceptional Points on Nonorientable Manifolds
Weijia Wang, Qicheng Zhang, Kun Zhang +2
Band degeneracies, ranging from Hermitian Dirac points to non-Hermitian exceptional points (EPs), play a central role in topological phase transitions. Beyond the topology of indiv…
Experimental Observation of Hidden Multistability in Nonlinear Systems
Kun Zhang, Qicheng Zhang, Shuaishuai Tong +3
Multistability, the coexistence of multiple stable states, is a cornerstone of nonlinear dynamical systems, governing their equilibrium, tunability, and emergent complexity. Recent…
Observation of Anti-helical Edge States in Acoustic Metamaterials
Tianzhi Xia, Qicheng Zhang, Chunyin Qiu
As a hallmark of the quantum Hall effect, chiral edge modes (CEMs) counterpropagate along the two parallel edges of a ribbon structure. However, recent studies demonstrate counteri…
Observation of anomalous Floquet non-Abelian topological insulators
Huahui Qiu, Shuaishuai Tong, Qicheng Zhang +2
Non-Abelian topological phases, which go beyond traditional Abelian topological band theory, are garnering increasing attention. This is further spurred by periodic driving, leadin…
Observation of Momentum-Band Topology in PT-Symmetric acoustic Floquet Lattices
Shuaishuai Tong, Qicheng Zhang, Gaohan Li +3
Momentum-band topology, which transcends conventional topological band theory, unlocks new topological phases that host fascinating temporal interface states. However, direct bulk…
Observation of Dislocation Non-Hermitian Skin Effect
Wenquan Wu, Qicheng Zhang, Liangjun Qi +3
The non-Hermitian skin effect (NHSE), a striking phenomenon where a large number of states accumulate toward open boundaries, has garnered significant attention in both fundamental…
Construction and Observation of Flexibly Controllable High-Dimensional Non-Hermitian Skin Effects
Qicheng Zhang, Yufei Leng, Liwei Xiong +4
Non-Hermitian skin effect (NHSE) is one of the most fundamental phenomena in non-Hermitian physics. Although it is established that one-dimensional NHSE originates from the nontriv…
Tracking Intrinsic Non-Hermitian Skin Effect in Lossy Lattices
Liwei Xiong, Qicheng Zhang, Xiling Feng +4
Non-Hermitian skin effect (NHSE), characterized by a majority of eigenstates localized at open boundaries, is one of the most iconic phenomena in non-Hermitian lattices. Despite no…
Discovery of Higher-Order Nodal Surface Semimetals
Huahui Qiu, Yuzeng Li, Qicheng Zhang +1
The emergent higher-order topological insulators significantly deepen our understanding of topological physics. Recently, the study has been extended to topological semimetals feat…
Observation of Hybrid-Order Topological Pump in a Kekule-Textured Graphene Lattice
Tianzhi Xia, Yuzeng Li, Qicheng Zhang +3
Thouless charge pumping protocol provides an effective route for realizing topological particle transport. To date, the first-order and higher-order topological pumps, exhibiting t…
Acoustic realization of projective mirror Chern insulators
Tianzi Li, Luohong Liu, Qicheng Zhang +1
Symmetry plays a key role in classifying topological phases. Recent theory shows that in the presence of gauge fields, the algebraic structure of crystalline symmetries needs to be…