Date: June 18 2021

Time: 16:00-17:00 (Beijing)

Webinar: Zoom Meeting (Zoom 会议) ID：775 921 8510

Password: Quantum

Topic: Microwave spectroscopy of hybrid superconductor-semiconductor qubits: Majorana Zero modes and Quantum Dot Transmons.

Speaker：Ramón Aguado，

Instituto de Ciencia de Materiales de Madrid (ICMM) and

Research Platform on Quantum Technologies, Consejo Superior de Investigaciones Científicas (CSIC)

Host:  Dong Liu，Research Scientist, BAQIS；Associate Professor, Department of Physics, Tsinghua University 

Abstract: Recent efforts have focused on replacing the weak link in the Josephson Junction (JJ) of a superconducting qubit by electrostatically-gateable technologies compatible with high magnetic fields [1]. Such alternatives are crucial in order to reach a regime relevant for readout of topological qubits based on Majorana zero modes (MZMs) [2]. In my talk, I will focus on JJs based on semiconducting nanowires that can be driven to a topological superconductor phase with MZMs. A fully microscopic theoretical description of such hybrid semiconductor-superconducting qubit allows to unveil new physics originated from the coherent interaction between the MZMs and the superconducting qubit degrees of freedom [3]. The corresponding microwave spectroscopy presents nontrivial features, including a full mapping of zero energy crossings and fermionic parity switches in the nanowire owing to Majorana oscillations [4]. Other effects, originated from quantum dots in the junction of a gate-tunable superconducting qubit will also be discussed.

About the speaker: Ramon Aguado is a senior scientist of the Spanish National Research Council (CSIC), Spain and works at the Institute of Materials Science Institute Madrid (ICMM) (Theory of Quantum Materials and Solid State Quantum technologies group https://wp.icmm.csic.es/tqe/).

He is a theoretical condensed matter physicist with more than 20 years of research experience, aiming at understanding experiments and making experimental predictions, in various areas revolving around new properties of quantum materials, mesoscopics physics, strongly correlated electrons and nanoelectronics. During the last few years, this activity has strongly focused on studying topological materials with applications in quantum technologies and Majorana physics (his latest publications can be found here: 

https://scholar.google.com/citations?hl=es&user=xWGWr2AAAAAJ&view_op=list_works&sortby=pubdate).

He is also the Vice President of the Condensed Matter Physics Division of the Spanish Physics Society.