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Fundamentals Solutions

01 /Quantum computers with magical advantage? 02 /Bra-ket notation 03 /Born rule 04 /Bloch sphere 05 /Measurement operators 06 /Experimental and theoretical measurements 07 /How to measure in any basis 08 /State decomposition 09 /Why every maximally entangled state is secretly a Bell state 10 /Coherence 11 /Relaxation 12 /Quantum materials: the environment of a qubit 13 /Introduction to quantum error correction (QEC) 14 /Multiqubit systems 15 /Multiqubit gates 16 /Entanglement 17 /Measuring multiqubit systems 18 /Superdense coding 19 /Teleportation 20 /Entanglement swapping

Experimental and theoretical measurements

In the video, Ben Criger shows how the current has a significant bump before arriving at the place where there is a state-dependent current. Do you think that the height of this first peak (which is independent of the spin state) matters? Why does it (not) matter?

No, in principle this doesn't matter, as long as there is a detectable difference in area under the whole curve. However, we must note that if the first peak is extremely high compared to the second peak, you could be limited by the measurement resolution. In general, the higher the signal you want to measure (or the broader the range), the lower your measurement resolution becomes. If the difference in area of the spin up and spin down states becomes smaller than the measurement resolution, you cannot distinguish the two states any more with the measurement.