Quantum Computing Architectures 2022/3

Gallium Arsenide is a ...

• superconductor

• semiconductor

• metal

• semimetal

Which hierarchy of energy scales is aimed at in spin-qubit experiments?

• confinement << thermal, chargin

• charging, thermal << confinement

• confinement, thermal << charging

• thermal << confinement, charging

What is the main role of a plunger gate?

• tune on-site energy

• tune tunnel barrier

• induce an ac magnetic field

• control QPC conductance

In a harmonic 2D quantum dot, doubling the confinement length leads to a confinement energy that is ...

• doubled

• reduced by a factor of 2

• reduced by a factor of 4

• unchanged

In a quantum dot, doubling the confinement length leads to a charging energy that is (roughly)...

• doubled

• reduced by a factor of 2

• reduced by a factor of 4

• unchanged

How is spin measured by the Elzerman technique?

• a magnetometer measures the B-field created by the spin

• spin is converted to mechanical rotation of a macroscopic body

• via spin-dependent optical selection rules

• spin is converted to charge

In Elzerman-type spin readout, we see a blip in the QPC current right after that ...

• the electron tunnels out from the dot

• the spin relaxes

• the electron enters the dot

• QPC bias voltage is switched on

What is the typical scale of the magnetic field applied in spin-qubit experiments?

• picotesla

• microtesla

• tesla

• kilotesla

What is the typical scale of the charging energy of a quantum dot?

• microelectronvolt

• millielectronvolt

• electronvolt

• kiloelectronvolt

• 1+3+2

• 1+1+1+1+2

• 4+2

• 3+3