ITAMP Topical Lunch Discussion
Date: FRIDAY, May 23
Time: 12:00-1:30 pm
Pizza will be served.
Location: B-106 @ Center for Astrophysics (60 Garden Street)
Directions: after entering the lobby of the CfA, turn right to enter the
hallway of the B building. In the hallway, turn right again, and B-106 is
there.
*Speaker*: Shannon Harvey (Harvard)
*Title: *Suppressing Qubit Dephasing using real-time Hamiltonian Parameter
Estimation
*Abstract: *Electron spins in semiconductor quantum dots hold promise for
quantum information processing (QIP) due to their potential for scalability
and miniaturization. However, interactions with the fluctuating nuclear
spins in the substrate cause these qubits to dephase in tens of
nanoseconds. In this talk, I will introduce the singlet-triplet qubit, a
type of semiconductor spin qubit, and discuss recent work in which we have
used techniques from Hamiltonian parameter estimation to increase the
coherence time in these qubits. Using a Bayesian approach, we rapidly
estimate the nuclear splitting faster than it fluctuates. We use this
estimate to update Hamiltonian control parameters in a way that makes the
qubit insensitive to nuclear noise, thereby increasing T2* from tens of
nanoseconds to over 2 us. This technique is straightforward to implement
and applicable to a wide array of qubits for QIP and metrological purposes.
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