Measurement-only quantum computation with Floquet Majorana corner modes

Majorana modes, typically arising at the edges of one-dimensional topological superconductors, are considered to be a promising candidate for encoding nonlocal qubits in fault-tolerant quantum computing. Here we exploit the two-dimensional geometry of Majorana corner modes in second-order topological superconductors to establish measurement-only quantum computation. It is shown that eight Majorana corner modes emerge when such systems are periodically driven, through which two nonlocal logical qubits and one nonlocal ancilla qubit can be constructed. Quantum gate operations can then be implemented by a designed series of parity measurements of topologically protected Majorana corner modes, accomplished via Mach-Zehnder type interference in the conductance between different corners of a second-order topological superconductor. Our theoretical proposal represents a scenario in which topologically protected single- A nd two-qubit gate operations can be carried out in a minimal setup, thus potentially establishing an efficient and low-cost building block for Majorana-based qubit architectures.