Compact localized boundary states in a quasi-1D electronic diamond-necklace chain

TL;DR

This paper introduces a novel quasi-1D diamond-necklace chain that hosts robust, compact localized zero-energy boundary states, which are promising for fault-tolerant quantum computing due to their non-decaying nature and potential for braiding.

Contribution

The study theoretically designs and experimentally demonstrates a new lattice geometry that supports compact localized zero-energy modes, overcoming limitations of exponential decay and hybridization in previous systems.

Findings

Discovery of a new boundary state in a diamond-necklace chain

Experimental realization of compact localized zero-energy modes

Potential application in fault-tolerant quantum computing

Abstract

Zero-energy modes localized at the ends of one-dimensional (1D) wires hold great potential as qubits for fault-tolerant quantum computing. However, all the candidates known to date exhibit a wave function that decays exponentially into the bulk and hybridizes with other nearby zero-modes, thus hampering their use for braiding operations. Here, we show that a quasi-1D diamond-necklace chain exhibits a completely unforeseen type of robust boundary state, namely compact localized zero-energy modes that do not decay into the bulk. We theoretically engineer a lattice geometry to access this mode, and experimentally realize it in an electronic quantum simulator setup. Our work provides a general route for the realization of robust and compact localized zero-energy modes that could potentially be braided without the drawbacks of hybridization.