Special CMSP Seminar TUESDAY 5 April at ICTP - 11.30 a.m. - Stefano CHESI - venue Stasi Seminar Room

[Condensed Matter Section]

Special Seminar in Condensed Matter Physics and
Statistical Physics


TUESDAY 5 APRIL at 11:30 a.m.
Luigi Stasi Seminar Room, ICTP Leonardo building


STEFANO CHESI (CSRC, Beijing, People's Republic of China)

"Dephasing Due to Nuclear Dpins in Large-Amplitude Electric Dipole Spin 
Resonance"


Abstract:
We have analyzed effects of the hyperfine interaction on electric dipole 
spin resonance (EDSR) when the amplitude of the quantum-dot motion 
becomes comparable or larger than the quantum dot's size. Away from the 
well-known small-drive regime, the important role played by transverse 
nuclear fluctuations leads to a gaussian decay of spin coherence with 
characteristic dependence on drive strength and detuning. A 
characterization of spin-flip gate fidelity, in the presence of such 
additional drive-dependent dephasing, shows that vanishingly small 
errors can still be achieved at sufficiently large amplitudes. Based on 
our theory, we analyze recent EDSR experiments relying on spin-orbit 
interactions or the slanting field of a micromagnet. We find that such 
experiments are already in a regime with significant effects of 
transverse nuclear fluctuations and the form of decay of the Rabi 
oscillations can be reproduced well by our theory. We will also briefly 
discuss other aspects of our research on single and double quantum dots, 
regarding the controlled generation of Dicke states in the nuclear spin 
bath and fast electron spin manipulation.