Quantum State of Cards: Is the Top Card Set Before Viewing?

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Discussion Overview

The discussion revolves around the quantum state of a deck of cards, specifically whether the top card can be considered to take on a value before it is viewed, and how quantum mechanics applies to macroscopic objects like cards compared to particles like electrons. The scope includes theoretical implications of quantum mechanics, decoherence, and the nature of superposition in relation to everyday objects.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants assert that the top card is fixed before being looked at, arguing that quantum effects do not apply at the scale of cards.
  • Others propose that while the probability of the top card being any specific card is 1/52 if the deck is well shuffled, this is contingent on the assumption of a thorough shuffle.
  • One participant suggests that superpositions of states can exist at scales where interactions are minimal, but at the scale of cards, interactions with the environment prevent such superpositions.
  • Another viewpoint indicates that decoherence does not lead to a classical state but rather reflects entanglement with the environment, complicating the idea of classical reality.
  • There is a discussion about the difficulty of achieving detectable quantum effects in macroscopic systems, with some arguing that while it is improbable for a card to be in superposition, it is not impossible.
  • Participants express uncertainty about the implications of the Schrödinger equation in this context, particularly regarding the feasibility of achieving superposition in practice.

Areas of Agreement / Disagreement

Participants generally disagree on the application of quantum mechanics to macroscopic objects like cards, with some asserting that superpositions are unlikely while others argue that they are theoretically possible. The discussion remains unresolved regarding the practical implications of these theories.

Contextual Notes

Limitations include the dependence on definitions of superposition and decoherence, as well as the unresolved nature of achieving detectable quantum effects in macroscopic systems.

Jim Frank
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I can understand that the state of a particle
is not known or even determined until it is viewed. What about a deck of cards that have been thoroughly shuffled and not looked at. Can the top card take on the value of any card before they are looked at or are they set at the time they are shuffled.

I understand that the wavelength of the card deck is quite a bit different that the wavelength of an electron so the quantum effects might not apply.

Any thoughts?
 
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The top card most certainly is fixed even before you have looked at it. Quantum effects do not occur at the scale of cards.

However, if the deck is well shuffled, the probability of the top card being any particular card is well described by 1/52, but this has more to do with your assumption that the deck is well shuffled.
 
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Orodruin said:
The top card most certainly is fixed even before you have looked at it. Quantum effects do not occur at the scale of cards.

However, if the deck is well shuffled, the probability of the top card being any particular card is well described by 1/52, but this has more to do with your assumption that the deck is well shuffled.

So the quantum effect is due to the size of the cards? It works on electrons but a card deck is too large. I understand, Thanks for your assistance.
 
I just want to state my view to see if it is in line with what the experts think. (not a pet theory, just my understanding)

Roughly, Things can have superpositions of states at scales where they are not interacting a lot with other things. A particle can have a superposition of states until it interacts with something that measures/observes it, or otherwise forces it to take a state (decoherence). The concept is "interaction in a thermodynamically irreversible way".

At the scale of cards, the cards are interacting with the atmosphere, other cards, your fingers, etc. The ink is interacting with the paper, etc etc. Simply put, there is no possibility of multiple states at the scale of the cards that would fulfill all the conditions of all those interactions.
 
meBigGuy said:
Roughly, Things can have superpositions of states at scales where they are not interacting a lot with other things. A particle can have a superposition of states until it interacts with something that measures/observes it, or otherwise forces it to take a state (decoherence). The concept is "interaction in a thermodynamically irreversible way".

In principle QM applies to macroscopic systems. Decoherence is simply entanglement with the environment. Decoherence does not produce a "classical state". It looks like we may have classical reality, but that is because we have not specified all the information of the environment (we get a density matrix).
 
I thought that decoherence indicated that one has pretty much pinned down the relationship between a thingy and its entangled environment. It appears like a classical state, but there is no such thing as a classical state (if you are accepting no-collapse decoherence). At the scope of a card in a deck, with all its physical uniqueness, it would be difficult for it to be so independent of its environment so as to be a superposition of two or more cards. That becomes the difficulty of producing detectable QM effects in macroscopic systems.
 
meBigGuy said:
At the scope of a card in a deck, with all its physical uniqueness, it would be difficult for it to be so independent of its environment so as to be a superposition of two or more cards.
I don't think it that would be the case - the card would be a superposition of two or more cards (if that is a prediction of the fundamental Schrödinger equation) while entangled with the environment
 
I did say difficult, meaning highly improbable. I didn't mean to imply impossible. Are you disagreeing with that?
 
meBigGuy said:
I did say difficult, meaning highly improbable. I didn't mean to imply impossible. Are you disagreeing with that?
I don't understand what you are asking. What are you referring to as difficult? If its about the cards being in superposition, I've answered that. If its about detecting macroscopic quantum effects, I didn't address that part of your post.
 
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What you said: If the Schrödinger equation for the system says they are in superposition while entangled with the environment, then they are (obviously).
I'm just saying that achieving that superposition in the lab would be "difficult", an unscientific subjective judgement. Are you saying that it would not be "difficult"?
I didn't think I was saying anything controversial. So maybe I'm not understanding some nuance of what you are saying.
 

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