Fig. 2: Simulation of a \(\sqrt{{\sigma }_{z}}\)-gate in an MSH T-structure.
From: Simulating topological quantum gates in two-dimensional magnet-superconductor hybrid structures

a–d Spatial plot of the zero-energy Nneq during consecutive times in the gate operation. White arrows (dots) indicate antiferromagnetic in-plane (ferromagnetic out-of-plane) alignment of the magnetic moments. Blue area indicates the superconducting substrate. e Majorana world lines obtained from a projection of the zero-energy Nneq onto the real space x-axis. f Time dependence of the fidelity Fe,o(t) for the even and odd parity states and of the geometric phase difference Δϕ. g Time- and energy-dependent Nneq at a site of the MSH network (see yellow arrow in (a)). h Fidelity F as a function of TR and ΔTR. Parameters are (μ, α, Δ, JS) = (−3.993, 0.9, 2.4, 5.2)te with a difference of ΔJ = 0.26te in the magnetic coupling between alternating sites on the T-structure, (TR, ΔTR) = (500, 50)τe and Γ = 0.01te for the inverse quasi-particle lifetime. These parameters, resulting in a topological superconducting gap of Δt ≈ 0.4te, were chosen in order to minimize (i) the localization length of the MZMs along the network, and thus (ii) the hybridization between the MZMs. Total system size for all results is 600 sites with dimension (20a0 × 30a0).