Quantum Computing Architectures 2022/4

What is the typical arrangement of Ga and As nuclear spins in a GaAs quantum dot at ~100 millikelvin?

• ferromagnetic alignment

• antiferromagnetic alignment

• helical magnetic ordering

• random, unpolarized

If a homogeneous electric field acts on a 1D quantum harmonic oscillator, then the oscillator ground-state wave function...

• becomes narrower

• becomes broader

• is shifted to a new equilibrium position

• does not change at all

What is the experimental fingerprint of spin-orbit-induced electrically driven spin resonance?

• anomalous resonance condition

• linear relation between Rabi frequency and ac gate-voltage amplitude

• linear relation between Rabi frequency and dc B-field

• imprecise quantum gates

Which pulse is used to induce spin dynamics in a conventional electron spin resonance experiment?

• dc magnetic-field pulse

• dc gate-voltage pulse

• ac magnetic-field pulse

• ac gate-voltage pulse

Which pulse is used to induce electrically driven spin resonance?

• dc magnetic-field pulse

• ac magnetic-field pulse

• dc gate-voltage pulse

• ac gate-voltage pulse

Which pulse is used to switch on and off the Coulomb-blockade configuration in the current-detected ESR experiment?

• ac magnetic-field pulse

• dc magnetic-field pulse

• ac gate-voltage pulse

• dc gate-voltage pulse

An electron moving along x in a 2DEG in the xy plane, subject to Rashba spin-orbit, feels an effective spin-orbit field ...

• along x

• along y

• along z

• neither

In spin resonance, a finite detuning from the resonance condition makes the Rabi oscillations ...

• slower and incomplete

• faster and incomplete

• slower and more complete

• faster and more complete

In the 1D quantum harmonic oscillator, the momentum operator p provides a nonzero matrix element ...

• between any two energy eigenstates

• only between the ground state and the first excited state

• only between nearest-neighbour energy eigenstates

• none of the others

In the perturbation theory applied to describe spin-orbit-mediated EDSR, which is the dominant (greatest) energy scale?

• orbital level spacing

• spin-orbit matrix element

• electric-field matrix element

• Zeeman energy