Fractional charge pumping of interacting bosons in one-dimensional superlattice

Zeng, Tian-Sheng; Zhu, Wei

doi:10.1103/physrevb.94.235139

Cited by 42 publications

(36 citation statements)

References 65 publications

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“…However, it was finally realized using ultracold atoms in optical lattices [20][21][22][23] . This remarkable progress has stimulated new theoretical proposals such as fractional pumping [24][25][26][27] and has further raised the importance of taking strong correlations into account, since the interactions of cold atoms are highly controllable.…”

Section: Introductionmentioning

confidence: 99%

Breakdown of topological Thouless pumping in the strongly interacting regime

et al. 2018

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We elucidate the mechanism for instability of topological Thouless pumping in strongly interacting systems from a viewpoint of symmetry-protected topological phases. If the protecting symmetries of the underlying topological phases change between noninteracting fermions and a bosonic system in the strong coupling limit, the symmetry protection argument enforces a gap closing and thereby predicts a breakdown of the topological pumping. We also demonstrate that, even in the weakly interacting regime where the bulk topological pumping is still robust, the interaction effects manifest themselves in the edge density profiles, leading to a unique feature of the pumping in open boundary conditions. Furthermore, an extension of the above results indicates that an analog of an interactioninduced phase of Weyl semimetals can be realized in the setup of the topological pumping. Our results provide a systematic understanding for the stability of topological pumping against strong interactions, to which the conventional perturbative argument cannot be applied. arXiv:1802.09780v2 [cond-mat.str-el]

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Section: Introductionmentioning

confidence: 99%

Breakdown of topological Thouless pumping in the strongly interacting regime

et al. 2018

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“… as suggested in [6,32].) As figure 2 (b) shows, the states at specific fillings have a non-vanishing Chern number while the others exhibit vanishing Chern number.…”

Section: Phase Diagrams Of Hard-core Bhmmentioning

confidence: 75%

Various topological Mott insulators and topological bulk charge pumping in strongly-interacting boson system in one-dimensional superlattice

2017

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In this paper, we study a one-dimensional boson system in a superlattice potential. This system is experimentally feasible by using ultracold atomic gases, and attracts much attention these days. It is expected that the system has a topological phase called a topological Mott insulator (TMI). We show that in strongly-interacting cases, the competition between the superlattice potential and the on-site interaction leads to various TMIs with a non-vanishing integer Chern number. Compared to the hard-core case, the soft-core boson system exhibits rich phase diagrams including various non-trivial TMIs. By using the exact diagonalization, we obtain detailed bulk-global phase diagrams including the TMIs with high Chern numbers and also various non-topological phases. We also show that in adiabatic experimental setups, the strongly-interacting bosonic TMIs exhibit the topological particle transfer, i.e., the topological charge pumping phenomenon, similarly to weakly-interacting systems. The various TMIs are characterized by topological charge pumping as it is closely related to the Chern number, and therefore the Chern number is to be observed in feasible experiments.Most of the previous studies have focused on the existence of non-trivial topological phases. Some numerical studies by using the density-matrix renormalization group method (DMRG) confirmed the existence of the non-trivial topological phase called topological Mott insulator (TMI) [6,7,9]. TMI is classified by a topological number such as the Chern number and it has a gap in the bulk but a gapless excitation in the (spacial as well as phase diagram) boundaries. A quantum Monte-Carlo simulation was also carried out to detect the topological phase [10]. However, the existence was verified only in a limited parameter regime, and detailed global phase diagrams are still lacking. In particular, strongly-correlated bosonic topological states with high Chern number in the bulk have not been clarified yet in a global parameter regime, nor it is understood well how the competition between the superlattice potential and the on-site repulsion determines the ground state of the system. Also, there is one important question, i.e., how the topological phases in the obtained phase diagrams are related with the topological charge pumping as bulk topological properties.In this paper, we shall study the above problems in the strongly-interacting boson system by using the exact diagonalization [22,23], and show explicitly relation between the equilibrium topological phases and the topological charge pumping in the adiabatic process by following [24]. From the relation, the global phase diagram plays a role of a guide for detecting various topological charge pumping in the experiments.This paper is organized as follows. The target boson model in the 1D optical superlattice is explained in section 2. Section 3 studies the ground states of the system for the hard-core boson limit. We explain the single particle (SP) equation, which is related to the famous Harper equation in 2D ...

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“…where we have used n ′ | T −j ′ q T j q |n = δ j,j ′ δ n,n ′ . Substituting equation (14) into equations (9)-(11), one can obtain [3],…”

Section: Maximally Localized Multi-particle Wannier Statesmentioning

confidence: 99%

“…From equation (14) and the translational symmetry of MPWSs, the c.o.m. position of the MPWS for the m-th band at time t is given as…”

Section: Maximally Localized Multi-particle Wannier Statesmentioning

confidence: 99%

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Multiparticle Wannier states and Thouless pumping of interacting bosons

Qin

Kivshar

et al. 2017

Phys. Rev. A

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The study of topological effects in physics is a hot area, and only recently researchers were able to address the important issues of topological properties of interacting quantum systems. But it is still a great challenge to describe multi-particle and interaction effects. Here, we introduce multi-particle Wannier states for interacting systems with co-translational symmetry. We reveal how the shift of multi-particle Wannier state relates to the multi-particle Chern number, and study the two-boson Thouless pumping in an interacting Rice-Mele model. In addition to the bound-state Thouless pumping in which two bosons move unidirectionally as a whole, we find topologically resonant tunneling in which two bosons move unidirectionally, one by the other, provided the neighboring-well potential bias matches the interaction energy. Our work creates a new paradigm for multi-particle topological effects and lays a cornerstone for detecting interacting topological states.

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Fractional charge pumping of interacting bosons in one-dimensional superlattice

Cited by 42 publications

References 65 publications

Breakdown of topological Thouless pumping in the strongly interacting regime

Breakdown of topological Thouless pumping in the strongly interacting regime

Various topological Mott insulators and topological bulk charge pumping in strongly-interacting boson system in one-dimensional superlattice

Multiparticle Wannier states and Thouless pumping of interacting bosons

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