Majorana Parity Qubits in Kitaev Chains

by Prof. Leo Kouwenhoven (QuTech, Delft University of Technology, The Netherlands)

Wednesday 21 Oct 2026, 10:30 → 11:30 Asia/Shanghai

Tsung-Dao Lee Institute/N4F-N400 - meeting room (Tsung-Dao Lee Institute)

Host: Prof. Chun-Xiao Liu  

Venue: TDLI Meeting Room N400

 

Abstract:

A Kitaev chain consists of semiconducting quantum dots coupled by nanoscale superconductors. Under appropriate conditions, the system realizes an effective p-wave topological superconductor, characterized by a bulk excitation gap and zero-energy states localized at its two ends. These end states—Majorana bound states (MBSs)—together form a single fermionic state whose occupation can be either even or odd. This fermion parity provides a basis for encoding a qubit in a pair of MBSs. Such a Majorana parity qubit is expected to be resilient to several sources of noise that typically cause decoherence and loss of quantum information.

We have realized Kitaev chains containing up to six quantum dots and operated a Majorana parity qubit in shorter chains. Although the chains used in these initial demonstrations are too short to provide full topological protection, the qubit encoding is the same as that envisioned for topological quantum computation. Ongoing work focuses on increasing the chain length, which is expected to enhance the qubit coherence time exponentially. 

 

Biography:

Dr. Leo P. Kouwenhoven, Distinguished University Professor at Delft University of Technology, former Partner Manager and Principal Researcher at Microsoft, former founding-director at QuTech and member of the Kavli Institute for NanoScience in Delft. PhD from Delft University of Technology (1992), postdoc research at UC-Berkeley, visiting professor at Harvard, member of both the Dutch Academy of Science and Arts and the US National Academy of Science.