AQA · A level Physics

Atom interferometer noise cancellation challenge

Can you get 100%? Use two atom interferometers to test phase, interference, common-mode noise cancellation and measurement sensitivity.

Read how the atom sensor cancels laser noise

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Question

8 marks

Answer all parts. Show your working and give units where appropriate.

1(a)

Two coherent matter-wave paths recombine with phase difference pi radians. State the type of interference expected and explain your answer.

[2 marks]

1(b)

During one measurement the phase readouts are

0.93 rad

and

0.77 rad

. Shared laser noise has added the same unknown phase to both readouts. Calculate the differential phase and explain why the shared noise cancels.

[3 marks]

1(c)

A future detector would search for a tiny signal that changes the relative phase of separated atom interferometers. Describe three checks needed to show that a measured differential phase is not an instrumental effect.

[3 marks]

Start the question to write your answer, receive marks and ask Sherlock Ohms for text help.