QDev seminar: Sebastian Mehl – University of Copenhagen

QDev seminar: Sebastian Mehl

Sebastian Mehl will give a theory seminar next Monday (26
Aug) at 1:15pm in D203. The title of his talk is "Noise-Protected Gate
for Six-Electron Double-Dot Qubit"

Noise-Protected Gate for Six-Electron Double-Dot Qubit

Singlet-triplet spin qubits in six-electron double quantum dots, in
moderate magnetic fields, can show superior immunity to charge noise.
This immunity results from the symmetry of orbitals in the second energy
shell of circular quantum dots: singlet and triplet states in this shell
have identical charge distributions.

In this talk I discuss singlet-triplet spin qubits in the
multi-electron sector of quantum dots and their coherence properties
under the influence of charge noise. I describe qubit manipulations in
the presence of charge noise from fluctuating charge traps. The
discussion shows that for optimal coherence properties the gate
operation switches rapidly between sweet spots deep in the (3,3) and
(4,2) charge stability regions; fidelities very close to one are
predicted if sub-nanosecond switching can be performed.