Quantum decoherence superposition of macroscopic object

In summary, Penrose has described an experiment to test the superposition of physical location in a small, macroscopic object. The experiment involves sending a photon through a half-mirror and bouncing it off a reflective object, causing a transfer of momentum and detectable movement. Penrose suggests that the time taken for decoherence could explain why we do not see quantum phenomena in our macro world, with the theory that it is inversely proportional to the complexity of the object. A review paper on this topic is available on arXiv without a subscription.
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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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1. What is quantum decoherence?

Quantum decoherence is the process by which a quantum system loses its coherence and behaves like a classical system. This means that the system's quantum properties, such as superposition and entanglement, are lost due to interactions with its environment.

2. What is a superposition of a macroscopic object?

A superposition of a macroscopic object refers to a quantum state in which the object exists in multiple states simultaneously. This is a fundamental principle of quantum mechanics and has been demonstrated with particles as large as buckyballs and viruses.

3. How does quantum decoherence affect superposition of macroscopic objects?

Quantum decoherence causes the superposition of a macroscopic object to collapse into a single state. This is due to the object's interactions with its surrounding environment, which causes it to behave like a classical object and lose its quantum properties.

4. Can quantum decoherence be reversed?

No, quantum decoherence is an irreversible process. Once a system loses its coherence, it cannot be regained. However, scientists are researching ways to minimize the effects of decoherence and prolong the superposition of macroscopic objects.

5. What are the applications of studying quantum decoherence and superposition of macroscopic objects?

The study of quantum decoherence and superposition of macroscopic objects has implications for quantum computing, quantum information processing, and understanding the boundary between the quantum and classical worlds. It also has potential applications in technologies such as quantum sensors and quantum communication.

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