I Counterfactual quantum computation on interferometer

artis
Messages
1,479
Reaction score
976
I watched a video on the topic by Sabine Hossenfelder.
Now it is said by many that this proves the photon "knows" something in advance because a certain state of a certain beam splitter can be probed in theory without the photon ever encountering that beam splitter because it took another path. The reason it took another path is also exactly because of the state of that beam splitter that it "probed" without actually probing it.

Now maybe I have got this wrong but what is so exotic in all of this?
Isn't this analogous to for example a loop of pipe with a pump and two parallel valves with different diameters.
If the water flows in such loop and I randomly close either of the valves the water then simply takes the route through the other open valve but given their different diameter I can know which path the water took by simply measuring the pressure before the valve.
So in this loop the "detector" would be a pressure sensor while in the quantum example the detector is a light detector and water is a laser beam and valves are beam splitters.

Now you might say that my valves are different diameter and that gives it away, but in the quantum example I think that translates into the angles and positions of the beam splitters , because only certain beam paths create constructive interference and therefore hit the detector.
So why is this then considered something "mystical" ?

 
  • Like
Likes Demystifier
Physics news on Phys.org
I am not sure if this belongs in the biology section, but it appears more of a quantum physics question. Mike Wiest, Associate Professor of Neuroscience at Wellesley College in the US. In 2024 he published the results of an experiment on anaesthesia which purported to point to a role of quantum processes in consciousness; here is a popular exposition: https://neurosciencenews.com/quantum-process-consciousness-27624/ As my expertise in neuroscience doesn't reach up to an ant's ear...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
I am reading WHAT IS A QUANTUM FIELD THEORY?" A First Introduction for Mathematicians. The author states (2.4 Finite versus Continuous Models) that the use of continuity causes the infinities in QFT: 'Mathematicians are trained to think of physical space as R3. But our continuous model of physical space as R3 is of course an idealization, both at the scale of the very large and at the scale of the very small. This idealization has proved to be very powerful, but in the case of Quantum...

Similar threads

Back
Top