Qubits (PH2299) – Physik
MasterComprehensive Practice Examination
(2026–2027 Latest Updated Edition)|
Question 1
Which superconducting circuit element provides the
nonlinearity necessary for constructing a qubit?
A. Capacitor
B. Inductor
C. Josephson Junction
D. Resistor
Answer: C
Rationale: The Josephson junction introduces a nonlinear
inductive element, allowing discrete quantum energy levels that
form the computational basis of superconducting qubits.
Question 2
,The most widely used superconducting qubit architecture in
current quantum processors is the:
A. Fluxonium-only qubit
B. Transmon qubit
C. Quantum dot qubit
D. Spin qubit
Answer: B
Rationale: The transmon qubit suppresses charge noise while
maintaining sufficient anharmonicity, making it the dominant
architecture in modern superconducting quantum computers.
Question 3
A transmon qubit primarily improves coherence by:
A. Increasing magnetic susceptibility
B. Reducing sensitivity to charge noise
C. Eliminating Josephson tunneling
D. Removing microwave control
Answer: B
,Rationale: Increasing the ratio of Josephson energy to charging
energy greatly suppresses charge-noise sensitivity.
Question 4
The operating temperature of superconducting quantum
processors is typically closest to:
A. 4 K
B. 1 K
C. 500 mK
D. 10–20 mK
Answer: D
Rationale: Dilution refrigerators cool superconducting qubits to
approximately 10–20 millikelvin, minimizing thermal
excitations.
Question 5
Quantum coherence time determines:
A. Processor weight
B. Classical memory size
, C. How long quantum information can be preserved
D. Microwave cable length
Answer: C
Rationale: Longer coherence times permit deeper quantum
circuits before decoherence destroys quantum information.
Question 6
The principal two-qubit interaction in many superconducting
processors is implemented using:
A. Optical fibers
B. Laser pulses
C. Microwave-controlled coupling
D. Mechanical resonators
Answer: C
Rationale: Microwave control pulses implement high-fidelity
two-qubit entangling gates between neighboring qubits.
Question 7
Which gate alone cannot generate entanglement?