Non-Hermiticity-induced reentrant localization in a quasiperiodic lattice

Abstract

In this paper, we demonstrate that the non-Hermiticity can induce reentrant localization in a generalized quasiperiodic lattice. Specifically, by considering a nonreciprocal dimerized lattice with staggered quasiperiodic disorder, we find that the localization transition can appear twice by increasing the disorder strength. We also unravel a multi-complex-real eigenenergy transition, whose transition points coincide with those in the localization phase transitions. Moreover, the impacts of boundary conditions on the localization properties have been clarified. Finally, we study the wavepacket dynamics in different parameter regimes, which offers an experimentally feasible route to detect the reentrant localization.

Coexistence of extended and localized states in one-dimensional non-Hermitian Anderson model

“…It was shown that an intermediate regime characterized by the coexistence of localized and extended states at different energies may occur 3,4 . The theoretical findings were confirmed in an experimental realization of a system with a single-particle mobility edge 5 .Recently, in non-Hermitian systems mobility edges have been explored for various 1D tight-binding models [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . In non-Hermitian systems, in comparison to the Hermitian ones, the mobility edges not only separate localized states from the extended states but also indicate the coexistence of complex and real energies.…”

“…Recently, in non-Hermitian systems mobility edges have been explored for various 1D tight-binding models [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] . In non-Hermitian systems, in comparison to the Hermitian ones, the mobility edges not only separate localized states from the extended states but also indicate the coexistence of complex and real energies.…”

“…On the other hand, in the nonreciprocal lattices, MBC leads to the coexistence of extended and localized eigenstates even in the absence of any onsite potentials. Note that such a coexistence was shown to appear only in the presence of tailored quasi-periodical potentials and coupling constant [7][8][9][10][11][12][13][14][15][16][17][18][19][20] . However, we see it in our system as a result of the boundary condition sensitivity of the nonreciprocal non-Hermitian systems.…”

Multiple skin transitions in two-band non-Hermitian systems with long-range nonreciprocal hopping

“…Non-Hermitian physics has attracted extensive attention, as non-Hermitian Hamiltonian can be used to explore the properties of open systems, quantum systems with gain and loss, as well as various classical systems [1][2][3][4][5][6][7][8][9][10][11]. In general, the energy band structure of non-Hermitian systems is complex, except for certain systems with pseudo-Hermiticity and parity-time (PT ) symmetry [12][13][14].…”

Topological Anderson insulators with different bulk states in quasiperiodic chains

“…On the other hand, growing effort has recently been made to explore topological and localization physics in non-Hermitian Hamiltonians or systems [80][81][82][83][84][85][86][87][88][89][90]. For instance, in the presence of non-Hermiticities from nonreciprocal hopping [63,[91][92][93][94] or complex on-site potential [69,[93][94][95][96][97], it has been revealed that topological phase transition characterized by a spectral winding number coincides with localization transition and (or) real-complex transition [63,69,79,97,98]. The non-Hermitian quasiperiodic systems may exhibit generalized mobility edge [93,96].…”