Wide-range-tunable Dirac-cone band structure in a chiral-time-symmetric non-Hermitian system

Sun, Liwei; Song, Z.

doi:10.1103/physreva.96.052121

Cited by 15 publications

(7 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unlike the expectation value of Pauli matrix σ α in the usual study [26], σ α k,0 = 0 for all α and α=x,y,z…”

Section: Ep Dynamics and Periodic Drivingmentioning

confidence: 75%

Quantum mold casting for topological insulating and edge states

Yang,

Song

2021

Preprint

Self Cite

View full text Add to dashboard Cite

We study the possibility of transferring fermions from a trivial system as particle source to an empty system but at topological phase as a mold for casting a stable topological insulator dynamically. We show that this can be realized by a non-Hermitian unidirectional hopping, which connects a central system at topological phase and a trivial flat-band system with a periodic driving chemical potential, which scans over the valence band of the central system. The near exceptional-point dynamics allows a unidirectional dynamical process: the time evolution from an initial state with full-filled source system to a stable topological insulating state approximately. The result is demonstrated numerically by a source-assistant QWZ model and SSH chain in the presence of random perturbation. Our finding reveals a classical analogy of quench dynamics in quantum matter and provides a way for topological quantum state engineering.

show abstract

“…Unlike the expectation value of Pauli matrix σ α in the usual study [26], σ α k,0 = 0 for all α and α=x,y,z…”

Section: Ep Dynamics and Periodic Drivingmentioning

confidence: 75%

Quantum mold casting for topological insulating and edge states

Yang,

Song

2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…In recent years, it has been attracted much attention and extensive studies have been demonstrated [41][42][43][44][45][46] . The degenerate zero modes take the role of topological invariant in the infinite N limit and are explicitly expressed as…”

Section: A Ssh Chainmentioning

confidence: 99%

Transition from degeneracy to coalescence: theorem and applications

Wang,

Zhang,

Song

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Exceptional point (EP) is exclusive for non-Hermitian system and distinct from that at a degeneracy point (DP), supporting intriguing dynamics, which can be utilized to probe quantum phase transition and prepare eigenstates in a Hermitian many-body system. In this work, we investigate the transition from DP for a Hermitian system to EP driven by non-Hermitian terms. We present a theorem on the existence of transition between DP and EP for a general system. The obtained EP is robust to the strength of non-Hermitian terms. We illustrate the theorem by an exactly solvable quasi-one dimensional model, which allows the existence of transition between fully degeneracy and exceptional spectra driven by non-Hermitian tunnelings in real and k spaces, respectively. We also study the EP dynamics for generating coalescing edge modes in Su-Schrieffer-Heeger-like models. This finding reveals the ubiquitous connection between DP and EP.

show abstract

“…Non-Hermitian topological systems with PT symmetry are of primary focus [76][77][78][79][80][81][82]. Other symmetries, such as chiral-time (CT ) and charge-parity (CP) symmetries, have been investigated [24,41,48,83,84]. The topological aspects of non-Hermitian systems, including edge modes [84,85], topological invariant [63,[86][87][88][89][90][91][92], band theory [92][93][94][95], topological pumping [56,59,[96][97][98], classification [99][100][101][102][103][104][105], high-order non-Hermitian topological systems [106][107][108][109][110][111], * jinliang@nankai.edu.cn semimetals [112][113][114]…”

Section: Introductionmentioning

confidence: 99%

Inversion symmetric non-Hermitian Chern insulator

Jin

Song

2019

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

We propose a two-dimensional non-Hermitian Chern insulator with inversion symmetry, which is anisotropic and has staggered gain and loss in both x and y directions. In this system, conventional bulk-boundary correspondence holds. The Chern number is a topological invariant that accurately predicts the topological phase transition and the existence of helical edge states in the topologically nontrivial phase. The band touching points are isolated and protected by the symmetry. The band touching affects the existence of helical edge states. Moreover, topologically protected helical edge states exist in the gapless phase for the system under open boundary condition in one direction. The detaching points between the edge states and the bulk states are predicted by the winding number associated with the vector field of average values of Pauli matrices. The non-Hermiticity also supports a topological phase with zero Chern number, where a pair of in-gap helical edge states exists. Our findings provide insights into the symmetry protected non-Hermitian topological insulators.

show abstract

Wide-range-tunable Dirac-cone band structure in a chiral-time-symmetric non-Hermitian system

Cited by 15 publications

References 53 publications

Quantum mold casting for topological insulating and edge states

Quantum mold casting for topological insulating and edge states

Transition from degeneracy to coalescence: theorem and applications

Inversion symmetric non-Hermitian Chern insulator

Contact Info

Product

Resources

About