Why is Schrodinger's Cat entangled? Or is it not?

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Discussion Overview

The discussion centers around the concept of Schrödinger's Cat, specifically addressing whether the cat is entangled and the implications of superposition and decoherence in this thought experiment. The scope includes theoretical interpretations of quantum mechanics and the nature of observation in quantum states.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the nature of entanglement in the context of Schrödinger's Cat, expressing confusion about how entanglement relates to superposition.
  • Another participant explains that the cat's state (alive or dead) is a superposition until the box is opened, at which point the observer becomes entangled with the cat's state.
  • A different viewpoint suggests that decoherence occurs before observation, leading to an improper mixed state, which complicates the understanding of entanglement and superposition in this scenario.
  • A participant expresses understanding after the explanation, indicating that the discussion has clarified their confusion regarding the entanglement aspect.

Areas of Agreement / Disagreement

Participants express differing views on the role of decoherence and the nature of entanglement in the Schrödinger's Cat scenario. The discussion remains unresolved regarding the implications of these concepts.

Contextual Notes

There are limitations in the discussion regarding the definitions of superposition and entanglement, as well as the assumptions made about the observer's role and the state of the cat prior to observation.

QuantumPixel
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Why is Schrödinger's Cat entangled? Or is it not? I recently saw a poster on deviantart that said this: http://browse.deviantart.com/art/WANTED-Schrödinger-s-Cat-130508078
It said it was in a superposition, that i get, but the entanglement? That i don't get.

-QuantumPixel
 
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since you understand the first part then the rest will be easy to understand hopefully. The fact that the state of the cat (dead or alive) is unknown before opening the box makes its state a superposition of both. When the box is opened by the observer, the observer becomes entangled with the cat and this forms an observer state corresponding to the cat being dead or alive, and hence the observer state is entangled with that of the cat.
 
Well actually in the Schrödinger's Cat thought experiment long before the box is opened decoherence has occurred transforming the pure state into an improper mixed state. Observationally there is no way to tell an improper mixed state from an actual one so its perfectly OK to assume it was in the observed state prior to observation - hey presto - issue resolved.

Thanks
Bill
 
Last edited:
Dundeephysics said:
since you understand the first part then the rest will be easy to understand hopefully. The fact that the state of the cat (dead or alive) is unknown before opening the box makes its state a superposition of both. When the box is opened by the observer, the observer becomes entangled with the cat and this forms an observer state corresponding to the cat being dead or alive, and hence the observer state is entangled with that of the cat.

Now i understand. Thanks for your time and contribution.

-QuantumPixel
 
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