Coexistence of extended and localized states in finite-sized mosaic Wannier-Stark lattices

Jun Gao; Ivan M. Khaymovich; Adrian Iovan; Xiao-Wei Wang; Govind Krishna; Ze-Sheng Xu; Emrah Tortumlu; Alexander V. Balatsky; Val Zwiller; Ali W. Elshaari

doi:10.1103/physrevb.108.l140202

arXiv · 2306.10831

Coexistence of extended and localized states in finite-sized mosaic Wannier-Stark lattices

Jun Gao·Ivan M. Khaymovich·Adrian Iovan·Xiao-Wei Wang·Govind Krishna·Ze-Sheng Xu·Emrah Tortumlu·Alexander V. Balatsky·Val Zwiller·Ali W. Elshaari

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Abstract

Quantum transport and localization are fundamental concepts in condensed matter physics. It is commonly believed that in one-dimensional systems, the existence of mobility edges is highly dependent on disorder. Recently, there has been a debate over the existence of an exact mobility edge in a modulated mosaic model without quenched disorder, the so-called mosaic Wannier-Stark lattice. Here, we experimentally implement such disorder-free mosaic photonic lattices using a silicon photonics platform. By creating a synthetic electric field, we could observe energy-dependent coexistence of both extended and localized states in a finite number of waveguides. The Wannier-Stark ladder emerges when the resulting potential is strong enough, and can be directly probed by exciting different spatial modes of the lattice. Our studies provide the experimental proof of coexisting sets of strongly localized and conducting (though weakly localized) states in finite-sized mosaic Wannier-Stark lattices, which hold the potential to encode high-dimensional quantum resources with compact and robust structures.

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Jun Gao, Ivan M. Khaymovich, Adrian Iovan, Xiao-Wei Wang, Govind Krishna, Ze-Sheng Xu, Emrah Tortumlu, Alexander V. Balatsky, Val Zwiller, Ali W. Elshaari. 2023-06-19. Coexistence of extended and localized states in finite-sized mosaic Wannier-Stark lattices. https://doi.org/10.1103/physrevb.108.l140202

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