QLunch: Max Geier

In this talk, we review current research directions of protected superconducting qubits. We start by discussing how different sources of noise limit the coherence of established superconducting qubits such as the transmon [1]. With this experience, we move forward to novel qubit architectures designed to protect the qubit towards noise, focusing on the zero-pi qubit [2]. We will further outline how gates can be performed in these qubits. If time permits, we will discuss a perpendicular direction of superconducting qubits, where quantum information is encoded in the occupation of individual Bogoliubov quasiparticles [3,4].

[1] Krantz et al., "A quantum engineer's guide to superconducting qubits", Appl. Phys. Rev. 6, 021318 (2019)

[2] Gyenis et al., "Moving beyond the Transmon: Noise-Protected Superconducting Quantum Circuits", PRX Quantum 2, 030101 (2021)

[3] Hays et al., "Coherent manipulation of an Andreev spin qubit", Science 373, 6553, pp. 430-433 (2021)

[4] Leijnse and Flensberg, "Introduction to topological superconductivity and Majorana fermions", Semicond. Sci. Technol. 27 124003 (2012)