On January 15,Physics Review Letters, a peer-reviewed, scientific journal Published a research article entitled“Nontopological Majorana zero modes in inhomogeneous spin ladders”, with the affiliation of Beihang University. Associate Professor Li Wei from the School of Physics of Beihang University involved in this work.
Asoneof the most important fundamental quasiparticles in condensed matter physics and the correlated quantum matter, the Majorana zero modesrecently has aroused immense interest among physical scientists.Finding a stable local zero-energy mode tocontrolMayorana qubits is a verypromisingsolid-state quantum information technology. This work proposes a new construction scheme, which is to"capture" local Majolana zero-energy modes in inhomogeneous spin ladderswith different coupling parameters.
TheArticleuses the BoseField Theoryto write the spin ladder model as the non-interactive Mayorana Fermi field, in which there are single and triplet Mayorana fermions with different positive and negative masses as well as different qualities. The symbols correspond to different magnetic quantum phases. In the discussion, the collaborators thought of coupling these quantum phases to form a similar "sandwich-like" structure, where the positive and negative masses of the Fermi field alternated, resulting in the Majolana zero-energy mode (see Fig.1). At the same time, the appearance of these interface Majolana bound states does not requirethetopological protection.
Li Wei and his longtimecollaborator A.Weichselbaumadopteda high-precision SU(2) density matrix renormalization group methodand did numerouscalculations,obtainingthe phase diagram of the spin ladder model with block interaction. Furthermore,the degree of degeneracy of the ground stateandentanglement spectrum havebeen carefully analyzed. Several potentialtheories were excluded and a stable Majolana zero-energy mode at the quantum phase interface of the RS-VBS_-RS spin ladder structurewas found.
Fig.1 (a) Schematic diagram of the quantum ladder "heterojunction" of the spin ladder. RS represents the "vertical" covalent bond crystal statewhileVBS_ represents the "negative" covalent bond crystal state.The singlet state Mayorana fieldof the two quantum phases has different qualities, and the exchange of quality symbols at the interface allows us to "capture" the local zero-energy mode.
Theworkwas supported by the National Natural Science Foundation of China,the National Key Research and Development Program of China(thenew method of quantum multi-body computing), Beihang Excellence Programfor Talents, and Beihang Youth Top Talent Fund.
The research article is available at:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.122.027201
