Quantum decoherence superposition of macroscopic object

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SUMMARY

The discussion centers on an experiment described by Roger Penrose that tests the superposition of a macroscopic object's physical location through quantum decoherence. The experiment involves sending a photon through a half-mirror to interact with a lightweight reflective object, allowing for momentum transfer that could lead to detectable movement. Penrose theorizes that the time taken for decoherence is inversely proportional to the object's size or complexity, potentially explaining the absence of observable quantum phenomena in the macroscopic world. A relevant review paper by Markus Aspelmeyer, Tobias J. Kippenberg, and Florian Marquardt titled "Cavity optomechanics" is cited for further reading.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly superposition and decoherence.
  • Familiarity with photon behavior in quantum experiments, including half-mirrors and momentum transfer.
  • Knowledge of macroscopic versus microscopic object behavior in quantum physics.
  • Access to academic papers, specifically those related to cavity optomechanics.
NEXT STEPS
  • Research the specifics of Penrose's experiment on superposition and decoherence.
  • Study the implications of the review paper "Cavity optomechanics" by Aspelmeyer et al.
  • Explore the relationship between object size and decoherence time in quantum systems.
  • Investigate other experiments that test quantum phenomena in macroscopic objects.
USEFUL FOR

Physicists, quantum mechanics researchers, and students interested in the intersection of quantum theory and macroscopic phenomena will benefit from this discussion.

Quantum of Solace
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I've seen a couple of lectures by Penrose where he describes an experiment to test superposition of physical location of a very small, but macroscopic object.

I can't find a reference to it online, but the experiment involved sending a photon through a half-mirror, and depending on the route taken, to bounce it off a very light reflective object, so that the light pressure would transfer momentum to it and move it. Whether or not the photon does this, it is rerouted to make the same 'choice' and same momentum-transferring bounce many hundreds(millions?) of times, such that the movement of the object would actually be detectable, but for a certain while the actual physical location would be in a superposition. If I remember correctly Penrose was saying there is a theory whereby the time taken for decoherence would be inversely proportional to the size (complexity?) of the object, and if this were to be able to be measured thus proven it would explain why we don't see quantum phenomena in our macro world.

Sorry for the terribly vague language but these were layman-directed lectures and I'm writing from memory, If someone has links to this experiment or other relevant studies I would very much like to read about these in more detail.
 
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There is review paper: Markus Aspelmeyer, Tobias J. Kippenberg, and Florian Marquardt, Cavity optomechanics, Rev. Mod. Phys. 86, 1391 (2014). It is available without a subscription on arXiv.
 
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