Symmetry-protected nodal phases in non-Hermitian systems

Budich, Jan Carl; Carlström, Johan; Kunst, Flore K.; Bergholtz, Emil J.

doi:10.1103/physrevb.99.041406

Cited by 236 publications

(162 citation statements)

References 60 publications

Supporting

Mentioning

152

Contrasting

Order By: Relevance

“…For the system with the local hybridization, EPs appear only at T EP and form a closed loop in the BZ. We note that it is not possible to define a vorticity at ω = 0 for this closed loop, which is different from the symmetry-protected exceptional ring in systems with chiral symmetry [48][49][50][51]. Therefore, we believe that this loop of exceptional points will change into isolated EPs connected by bulk Fermi arcs when taking into account a momentum-dependent self-energy.…”

Section: Relation Between Kondo Temperature and Tep In F -Electrmentioning

confidence: 91%

Relationship between exceptional points and the Kondo effect in f -electron materials

2020

View full text Add to dashboard Cite

We study the impact of nonhermiticity due to strong correlations in f -electron materials. One of the most remarkable phenomena occurring in nonhermitian systems is the emergence of exceptional points at which the effective nonhermitian Hamiltonian cannot be diagonalized. We here demonstrate that the temperature at which exceptional points appear around the Fermi energy is related to the Kondo temperature. For this purpose, we study the periodic Anderson model with local and nonlocal hybridization in the insulating and metallic regimes. By analyzing the effective nonhermitian Hamiltonian, which describes the single-particle spectral function, and the temperature dependence of the magnetic moment, we show that exceptional points appear at the temperature at which the magnetic moment is screened. This temperature corresponds to the Kondo temperature. These results suggest that the well-known crossover between localized and itinerant f -electrons in these materials is related to the emergence of exceptional points in the single-particle spectral function at the Fermi energy. Viewing exceptional points in the combined momentum-frequency space, we observe that the exceptional points in the effective Hamiltonian form a one-dimensional manifold which changes its structure around the Kondo temperature. arXiv:1905.12287v2 [cond-mat.str-el]

show abstract

Section: Relation Between Kondo Temperature and Tep In F -Electrmentioning

confidence: 91%

Relationship between exceptional points and the Kondo effect in f -electron materials

2020

View full text Add to dashboard Cite

show abstract

“…Thus, we can obtain an exceptional ring and torus in two-and threedimensional systems with chiral symmetry. Note that the Fermi surface emerges in the region surrounded by exceptional manifold, called Femi volumes 80 , which are open regions of vanishing real part of the energy gap and have the same dimension as the system itself.…”

Section: A Symmetry Protection Of Exceptional Torus For Two Band Modmentioning

confidence: 99%

Chiral-symmetry protected exceptional torus in correlated nodal-line semimetals

2019

View full text Add to dashboard Cite

We analyze a diamond-lattice Hubbard model with the spatially modulated Hubbard interaction. Our dynamical mean-field analysis with special emphasis on non-Hermitian properties elucidates that the gapless nodal line changes into symmetry-protected exceptional torus (SPET) at the Fermi level enclosing the three-dimensional open Fermi surface, which is unique to non-Hermitian physics with chiral symmetry. Furthermore, we also elucidate the effects of the SPETs on the magnetic response; our results based on the random-phase approximation combined with the the dynamical mean-field theory shows that SPETs enhance the magnetic susceptibility at the weakly correlated sites, exemplifying effects of non-Hermitian degeneracies on responses to external fields.

show abstract

“…The nontrivial bulk topology in Hermitian systems can * wuyajie@xatu.edu.cn † Junpeng.Hou@utdallas.edu be detected by defects, such as edges, π-flux, dislocations and vortices [48][49][50][51][52][53]. When it comes to non-Hermitian systems, stable edge states could also exist at the interface between topological and trivial phases [54][55][56][57][58][59][60][61][62]. These topological states, originated from bulk topologies, are immune to local symmetry-preserved perturbations.…”

Section: Non-hermitian Hamiltonian Captures Essentials Of Open Systemmentioning

confidence: 99%

Symmetry-protected localized states at defects in non-Hermitian systems

Hou

2019

Phys. Rev. A

View full text Add to dashboard Cite

Understanding how local potentials affect system eigenmodes is crucial for experimental studies of nontrivial bulk topology. Recent studies have discovered many exotic and highly non-trivial topological states in non-Hermitian systems. As such, it would be interesting to see how non-Hermitian systems respond to local perturbations. In this work, we consider chiral and particlehole -symmetric non-Hermitian systems on a bipartite lattice, including SSH model and photonic graphene, and find that a disordered local potential could induce bound states evolving from the bulk. When the local potential on a single site becomes infinite, which renders a lattice vacancy, chiral-symmetry-protected zero-energy mode and particle-hole symmetry-protected bound states with purely imaginary eigenvalues emerge near the vacancy. These modes are robust against any symmetry-preserved perturbations. Our work generalizes the symmetry-protected localized states to non-Hermitian systems.

show abstract

Symmetry-protected nodal phases in non-Hermitian systems

Cited by 236 publications

References 60 publications

Relationship between exceptional points and the Kondo effect in f -electron materials

Relationship between exceptional points and the Kondo effect in f -electron materials

Chiral-symmetry protected exceptional torus in correlated nodal-line semimetals

Symmetry-protected localized states at defects in non-Hermitian systems

Contact Info

Product

Resources

About