In a monumental breakthrough, a collaborative research team led by Prof. Junwei Liu from the Hong Kong University of Science and Technology (HKUST) and Prof Jinfeng Jia and Prof Yaoyi Li from Shanghai Jiao Tong University (SJTU) has made a remarkable discovery – the world’s first multiple Majorana zero modes (MZMs) in a single vortex of the superconducting topological crystalline insulator SnTe. This discovery, recently published in Nature, has opened up a new avenue towards achieving fault-tolerant quantum computers.
A Unique Quasiparticle with Non-Abelian Statistics
MZMs are zero-energy topologically nontrivial quasiparticles in superconductors that exhibit non-Abelian statistics, allowing for inequivalent braiding sequences. This distinguishing characteristic sets MZMs apart from ordinary particles like electrons or photons, where different braiding always leads to the same outcome. The inherent protection of MZMs from local perturbations makes them an ideal candidate for robust fault-tolerant quantum computation.
While significant progress has been made in engineering artificial topological superconductors, the manipulation and braiding of MZMs have proven to be extremely challenging due to their separation in real space. This spatial discrepancy complicates the required movements for hybridization, posing a significant hurdle in harnessing the full potential of MZMs for quantum computing applications.
The collaborative research team took a novel approach by leveraging crystal symmetry to control the coupling between MZMs in the superconducting topological crystalline insulator SnTe. By exploiting the unique feature of crystal-symmetry-protected MZMs, they were able to eliminate the bottlenecks associated with the spatial separation of MZMs. This breakthrough opens up new possibilities for the detection and manipulation of crystal-symmetry-protected multiple MZMs.
The experimental group at SJTU observed significant changes in the zero-bias peak, a strong indicator of MZMs, in the SnTe/Pb heterostructure under tilted magnetic fields. Subsequently, the theoretical team at HKUST conducted extensive numerical simulations to unequivocally demonstrate that the anisotropic responses to tilted magnetic fields stem from crystal-symmetry-protected MZMs. This harmonious collaboration between theory and experimentation has enabled the exploration of novel properties in vortex systems beyond just crystal-symmetry-protected MZMs.
This groundbreaking research marks a significant milestone in the field of quantum computation, paving the way for the experimental validation of non-Abelian statistics and the development of new types of topological qubits and quantum gates based on crystal-symmetry-protected multiple MZMs. The discovery of multiple MZMs in a single vortex of SnTe not only expands our understanding of topological superconductors but also propels us closer to the realization of fault-tolerant quantum computers.