- In quantum key distribution, when do Alice and Bob communicate about their choice of inserting a beam splitter or
not?
a). Before Alice sends her photon.
b). After Alice sends the photon, but before Bob detects it.
c). After Alice has sent the photon and Bob has detected it.
d). Never.
- Which statement below is correct?
a). Quantum teleportation requires classical communication, while entanglement swapping requires only quantum
communication.
b). Quantum teleportation allows to send quantum states faster than the speed of light, but not classical information.
c). Quantum teleportation is limited by the speed of light because it requires classical communication of the input state.
d). Quantum teleportation requires classical communication of the joint measurement results
- In the diagram below, what is the probability of the detection outcome A’1-B’2 ? (Here, N/8 denotes an extension by 1/8
wavelength, and 3N/8 denotes an extension by 3/8 wavelength.)
a). 0
b). 1/4
c). 1/2
d). 1/4 + 1/(4√2)
e). 1/4 -1/(4√2)
- In the diagram below, when the path is extended by length L, then the probability of the detection outcome A’2-B’1
becomes 1/4. What will this probability be when the extension becomes L/2?
a). 0
b). 1/16
c). 1/8
d). 1/4
e). 1/4 +1/(4√2)
- In the diagram below, when the path is extended by length L, and an NDD is placed on the other path, then the
probability of the detection outcome A’2-B’1 becomes 1/4. What will this probability be when the extension becomes 2L?
a). 0
b). 1/4 + 1/(4√2)
c). 1/4 -1/(4√2)
d). 1/4
e). 1/2
- In the diagram below, the source S emits a single photon. What is the probability of having a click at detector A? BS is a
regular beam splitter, and M is a mirror.
a). 0%
b). 25%
c). 50%
d). 75%
e). 100%
- In the diagram below, the source S emits a single photon, and an NDD is placed in the upper path. What is the probability
of having a click at detector A? BS is a regular beam splitter, and M is a mirror.
a). 0%
b). 25%
c). 50%
d). 75%
e). 100%
- In the diagram below, the source S emits a single photon, and two NDDs are placed as indicated. What is the probability of
having a click at detector A? BS is a regular beam splitter, and M is a mirror.
a). 0%
b). 25%
c). 50%
d). 75%
e). 100%
