SKM 2023 – wissenschaftliches Programm

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SYQD: Symposium Real-Time Measurements of Quantum Dynamics

SYQD 1: Real-Time Measurements of Quantum Dynamics

SYQD 1.1: Hauptvortrag

Donnerstag, 30. März 2023, 09:30–10:00, HSZ 01

Real-time measurement and control of spin dynamics in quantum dots — •Seigo Tarucha — Center for Emergent Matter Science and Quantum Computing, RIKEN, Wako, Saitama 351-0198, Japan

The progress of quantum information technologies using semiconductor quantum dots has provided novel methods to control and detect quantum dynamics of single electron spins. The quantum information unit (qubit) is prepared using a concept of electron spin resonance and the qubit dynamics is dependent on dephasing or fluctuations of the resonance frequency through interactions with electromagnetic environment. In this talk I will first show experiments on real-time measurements of fluctuating frequencies of the respective spins and exchange-coupled two spins in a double quantum dot. The quantum dot is made in natural Si and also isotopically purified 28Si, which have different magnetic environments of nuclear spins. We use Ramsey interference sequence to derive the auto- and cross-power spectral density of the fluctuating resonance frequencies and address the influences from magnetic and charge noise in the respective quantum dots. We find an evident cross-correlation between two spins arising from the charge noise and devise a model of two-level fluctuators to account for the cross-correlation. Lastly I will show feedback control to suppress the influence on the spin dynamics from the environment.