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PRODID:UW-Madison-Physics-Events
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SEQUENCE:1
UID:UW-Physics-Event-8287
DTSTART:20230614T140000Z
DTEND:20230614T160000Z
DTSTAMP:20260414T033337Z
LAST-MODIFIED:20230530T154422Z
LOCATION:https://uwmadison.zoom.us/j/97978600223?pwd=VzVVQ3dYQ21JUWczb
 01RQmRkdis0QT09
SUMMARY:Characterization of noise sources in semiconductor qubit devic
 es\, Graduate Program Event\, Yujun Choi\, Department of Physics Gradu
 ate Student
DESCRIPTION:Quantum computing has garnered substantial attention in re
 cent decades for its potential applications across various domains suc
 h as cybersecurity\, chemical engineering\, logistics optimization\, d
 ata search\, drug synthesis\, and machine learning. However\, practica
 l utilization of quantum computing faces significant challenges due to
  considerable overhead. Even with the aid of state-of-the-art quantum 
 error correction codes\, millions of physical quantum bits (qubits) ar
 e required. This necessity arises from limitations in gate fidelities 
 of qubits resulting from environmental noise. Therefore\, it is impera
 tive to investigate noise source characteristics and devise strategies
  to mitigate their impact on qubits.<br>
\n<br>
\nSemiconductor qubits
  offer a promising platform that can be readily expanded by leveraging
  existing semiconductor industry facilities. In semiconductor devices\
 , an array of detrimental noise sources\, such as charge noise\, hyper
 fine noise\, evanescent-wave Johnson noise\, and phonon-induced noise\
 , can degrade coherence of the qubits. This dissertation specifically 
 focuses on charge noise (1/f noise).<br>
\n<br>
\nThe dissertation com
 mences by introducing a methodology to characterize diverse noise sour
 ces through the measurement of coherence times while rotating a vector
  magnet in a spin qubit device. Subsequently\, it presents the applica
 tion of a technique called noise source driving to enhance coherence o
 f qubits. This approach involves applying an oscillating electric fiel
 d to the charge noise sources. Following this\, the dissertation eluci
 dates a plausible mechanism explaining the pulse-induced resonance fre
 quency shift of a qubit with fluctuations of two-level systems. Lastly
 \, the dissertation discusses future research directions and concludes
  with closing remarks
URL:https://www.physics.wisc.edu/events/?id=8287
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