[Now Registering]The 12th Quantum Solid Flagship Seminar
Date/Time
Wednesday, June 24, 2026, 1:15 PM – 2:30 PM (JST)
Venue
・On-site: Multipurpose Hall, 1st Floor, North (EEI) Bldg. 3 Ookayama Campus, Institute of Science Tokyo
Map
・Online (Zoom): The connection details will be provided to registered participants.
Chair
Prof. Mutsuko Hatano (Science Tokyo)
Lecturer
Prof. Ádám Gali
HUN-REN Wigner Research Centre for Physics, Budapest, Hungary
Title
Point defect qubits in solids
Abstract
Point defects in wide-band-gap semiconductors can realize single, optically addressable electron spins that operate as quantum bits even at room temperature, making them prime candidates for quantum communication, quantum computing, and nanoscale quantum sensing. In this talk I give an overview of the physics of point defect qubits and show how their key figures of merit — optical spin initialization and readout, coherence time, and emission wavelength — emerge from the interplay of electronic structure, electron–phonon coupling, and spin–orbit interaction.
I first illustrate, on the example of the G center in silicon, how ultraprecise magneto-optical spectroscopy combined with first-principles theory enables the identification and even the deliberate engineering of point defects. I then turn to the nitrogen-vacancy (NV) center in diamond, the paradigmatic solid-state qubit, and present an ab initio theory of its optically detected magnetic resonance (ODMR) readout, in which dynamic and pseudo Jahn–Teller effects play a decisive role. The NV center acts as a versatile quantum sensor of magnetic and electric fields, temperature, and strain at the nanoscale; I show recent results from our laboratory ranging from coherent spin control to vector magnetometry. Finally, I discuss the search for alternative qubits emitting in the near-infrared and telecom windows, in particular the divacancy-related PL6 center in silicon carbide, whose bioinert, engineered surfaces open the way to in vivo sensing, and whose host material offers a mature semiconductor technology platform for the mass production of quantum sensors.
Language
English
Registration fee
Free of Charge
Participants
General Public & Students
Registration
https://forms.gle/1YsRfRjTEUPFTfNa8
Contact
HQ, Quantum Metrology and Sensing
Email: hq[at]qleap.titech.ac.jp
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