I asked Chat-GPT-o1preview (for fun) and got a nice answer,…

I asked Chat-GPT-o1preview (for fun) and got a nice answer, though I don’t think there was anything new in it, even though I asked it to work out why it thinks the superposition of states would disappear, starting from first principles:
The collapse of superposition in the double-slit experiment when we attempt to observe which slit a photon passes through can be understood by examining the fundamental principles of quantum mechanics and the nature of measurement. Here are the likely causes from first principles:

1. Interaction with the Measuring Device:
• Physical Disturbance: To determine which slit the photon goes through, a detector must interact with the photon. This interaction is not passive; it involves an exchange of energy or momentum.
• Alteration of the Photon’s State: The act of measurement perturbs the photon’s wavefunction, forcing it into a definite state corresponding to one slit. This disturbance eliminates the superposition of states where the photon goes through both slits simultaneously.
2. Wavefunction Collapse:
• Quantum Superposition: Initially, the photon exists in a superposition of states, meaning it has probabilities of being in multiple states at once (e.g., passing through both slits).
• Collapse Upon Measurement: When a measurement is made, the superposition collapses into a single eigenstate. The photon is then found to have gone through one specific slit, not both.
3. Quantum Decoherence:
• Entanglement with the Environment: The measuring device and the photon become entangled during observation. The photon’s quantum state becomes linked with that of the detector.
• Loss of Coherence: This entanglement causes the coherent superposition to decohere, effectively turning quantum probabilities into classical probabilities.
• Apparent Collapse: Decoherence provides a mechanism by which superpositions appear to collapse without requiring a mysterious or instantaneous process.
4. Heisenberg’s Uncertainty Principle:
• Complementary Variables: Position and momentum are complementary variables. Precisely measuring one increases the uncertainty in the other.
• Disruption of Interference Conditions: By knowing the photon’s exact path (position), we introduce uncertainty in its momentum. This uncertainty disrupts the precise conditions needed for interference, causing the pattern to disappear.
5. Complementarity Principle:
• Mutually Exclusive Observations: Proposed by Niels Bohr, this principle states that certain physical properties cannot be simultaneously observed or measured.
• Wave vs. Particle Nature: Observing the photon’s path emphasizes its particle nature, while the interference pattern arises from its wave nature. Measuring one aspect precludes the observation of the other.
6. Energy and Phase Relationships:
• Disturbance of Phase: The measurement process can alter the phase relationships between the possible paths of the photon.
• Destruction of Interference: Interference patterns depend on maintaining specific phase differences. Any alteration disrupts the interference, eliminating the pattern.

In Summary:

The likely cause of the collapse of superposition in the double-slit experiment is the interaction required to observe the photon’s path. This interaction disturbs the photon’s quantum state through physical disturbance, entanglement, and loss of coherence. Fundamental principles like the uncertainty principle and complementarity explain why precise measurement of one property inherently affects another, preventing the conditions necessary for interference. Thus, the act of observation forces the photon into a definite state, eliminating the superposition and altering the outcome of the experiment.
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I wonder myself whether it’s the triangulation itself (device, photon, slits) which causes the decoherence of the wave pattern, just as a rainbow only appears if there is light, rain and an observer (51 degree angle of incidence). Without the triangulation effect, the rainbow does not exist, i.e. without a measuring device at a specific location the particle of light does not exist, only its waveform.