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PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-9305
DTSTART:20250627T180000Z
DTEND:20250627T200000Z
DTSTAMP:20260413T133139Z
LAST-MODIFIED:20250624T153723Z
LOCATION:5310 CH
SUMMARY:High-fidelity gates in a disordered Si/SiGe wiggle well with s
 trong spin-orbit coupling\, Preliminary Exam\, Hudaiba Soomro\, Physic
 s PhD Graduate Student
DESCRIPTION:Silicon-based single-electron spin qubits commonly use mic
 romagnets to create an artificial spin orbit coupling (SOC) for Electr
 ic Dipole Spin Resonance (EDSR)\; however\, this approach faces scalab
 ility challenges. Previously\, it has been shown that the Wiggle Well 
 may sufficiently enhance the otherwise weak SOC in the conduction band
  of Si\, allowing for implementation of a strong EDSR protocol\; previ
 ous calculations indicate that Rabi frequencies exceeding 500MHz/T may
  be possible [1]. However\, SiGe random-alloy disorder causes spatial 
 variations that have not been fully accounted for in these calculation
 s. In this work\, we show that alloy disorder gives rise to two main e
 ffects relevant for EDSR: the generation of a strong valley dipole (pr
 oviding an additional EDSR mechanism)\, and randomization of valley pa
 rameters (providing a position-dependent Rabi frequency). We find that
  the valley-dipole contribution to the Rabi frequency is particularly 
 pronounced in the low-valley-splitting regime. Additionally\, we incor
 porate charge noise effects and compute the position-dependent T2\,Rab
 i time\, the dephasing rate\, and the quality factor\, finding quality
  factors of the order of 103 . Finally\, we identify dephasing-protect
 ed ‘sweet spots’ where the qubit is resilient to charge noise.”

 \n 
\n[1] B. D.  Woods\, et al.\, Phys. Rev. B 107\, 035418 (2023)
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URL:https://www.physics.wisc.edu/events/?id=9305
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