• Welcome to Religious Forums, a friendly forum to discuss all religions in a friendly surrounding.

    Your voice is missing! You will need to register to get access to the following site features:
    • Reply to discussions and create your own threads.
    • Our modern chat room. No add-ons or extensions required, just login and start chatting!
    • Access to private conversations with other members.

    We hope to see you as a part of our community soon!

Let's discuss Schrodinger's cat

Martin

Spam, wonderful spam (bloody vikings!)
But seriously, what is the point being made by the cat in a box thing? And is it related to Heisenbergs uncertainty principle?
 

ChristineM

"Be strong", I whispered to my coffee.
Premium Member
In fact all I have left is Galaxies, 2 semesters of quantum, and the rest is research & thesis

I do like galaxies
galaxy-darker-block-110g.jpg
 

Brickjectivity

Turned to Stone. Now I stretch daily.
Staff member
Premium Member
I also never really got this until this thread. If I understand it right, as of now: the point of the cat in a box is that its ridiculous, that the superposition idea can be taken too far. It is convenient but inaccurate to think of superposition as physical. It is a confusing quantum measurement which people are trying to understand by imagining it as two things in one space. Is this the point?
 

Deidre

Well-Known Member
But seriously, what is the point being made by the cat in a box thing? And is it related to Heisenbergs uncertainty principle?
The point being that the cat's actual state only matters if there is an observer of said state. For example, I may misplace my car keys, and if I remember where I've misplaced them, I can hope that they're still there when I go to find them. But, they're only actually ''there''...if as the observer, I've found them. In some ways I disagree, because to me, if the cat is dead, it's dead regardless if I'm observing its state or not. But, Schrodinger had different ideas....
 

sayak83

Veteran Member
Staff member
Premium Member
So, I get that Schrodinger came up with a thought experiment to disprove the common interpretation of quantum mechanics. Some have claimed that it wasn't so much an experiment, as an illustration. Nonetheless, we all know the gist of Schrodinger's cat. But, it isn't that the cat is both dead and alive (that doesn't make sense), it's that the possibility of the cat being dead or alive until one observes its actual state, is what Schrodinger was trying to illustrate?

To3a2L8.jpg
The cat is either dead or alive, not both. The dissipation of quantum coherence through millions of interactions between the atoms in the cat's body means quantum superpisition terms would cancel away to zero and only the classical results remain.
 

Deidre

Well-Known Member
The cat is either dead or alive, not both. The dissipation of quantum coherence through millions of interactions between the atoms in the cat's body means quantum superpisition terms would cancel away to zero and only the classical results remain.
Yes, I stated that as part of the OP, but I like your elaboration.
 

Ben Dhyan

Veteran Member
Exactly. They are unbroken. The fact that they will fall and break as soon as you open the cupboard, is a mere conjecture, based upon probability.
But it didn't happen.
;)
Hmmm, I had always understood that the process of observing the 'cat' at the quantum level to determine its state necessitated a technical process that unfortunately due to the sensitivity issues alters the original state one is trying to observe?
 

LegionOnomaMoi

Veteran Member
Premium Member
The cat is either dead or alive, not both. The dissipation of quantum coherence through millions of interactions between the atoms in the cat's body means quantum superpisition terms would cancel away to zero and only the classical results remain.
The dissipation of quantum coherence is at best irrelevant here and more likely a reformulation of exactly the same kinds of problems Schrödinger was addressing without actually addressing them at all, merely pushing the problems back (or further) without realizing what the issues are:
“It is sometimes claimed that decoherence alone provides the solution to the measurement problem. This is simply wrong...the fact that decoherence doesn’t solve the measurement problem should already be evident from the fact that coherence—the ability of the superposed wave packets to interfere—plays no role in its formulation. The point of Schrödinger’s cat argument is that the wave functions of a dead cat and a living cat are there at the same time, and that they are equally “real”, not that they overlap in configuration space and produce interference. This is something that Schrödinger understood very well. As long as we insist that the wave function provides a complete description of the physical state, the result of the measurement is still “dead cat AND live cat”, not “dead cat OR live cat”.” (p. 46; emphasis added)
Dürr, D., & Lazarovici, D. (2020). Understanding Quantum Mechanics: The World According to Modern Quantum Foundations. Springer.
Recall that Schrödinger was writing a few months after the (now infamous) EPR paper, and explicitly in response to and in agreement with the points made principally by the lead author (Einstein), with whom he had been communicating and who probably gave him (in a letter) the basic idea of a macroscopic superposition via a microscopic "trigger" (Einstein's example involved an explosion). The EPR paper is called "EPR" so frequently that it is sometimes forgotten the original title was "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?"
It was completeness in particular that Schrödinger was concerned with. Hence his analogy (in the same paper) of the fundamental difference between a sharp, clear photo of mist or clouds and a blurred photograph. Physicists at the time seemed to be content with explanations that involved a quantum mechanical realm that was complementary to a classical one, but necessarily distinguished from it. In particular, he was producing a reductio argument against the idea that the state vector or wavefunction could be considered a complete description of a physical system. Logically, introducing nonlinearities into the evolution of the wavefunction and/or stochastic (spontaneous) "collapses" induced by natural "measurements" either via the environment of the system or its internal structures or both don't play any role here. Such solutions are, at best (and naively) simply new fangled versions of the Heisenberg cut or von Neumann's chain without explicit references to measurements or observers. These "solutions" don't address the fact that superposition states in quantum mechanics are never observed, merely postulate mechanisms to explain how something like the measurement "collapse" can happen "naturally", but as Schrödinger's cat paradox already contains a macroscopic system coupled to a superposition state, all you are doing is trying to reintroduce the very explanations Schrödinger was showing to be inadequate, namely the point at which quantum mechanical descriptions are supposed to yield to the emergence of the (approximately) classical world of experience:

“A common misconception is that the paradox is easily solved by just invoking decoherence, which explains why it is impossible in practice to observe quantum interferences between states where a cat is alive or dead...Actually, (de)coherence is irrelevant in Schrödinger’s argument: the cat is actually a symbol of the absurdity of a quantum state that encompasses two incompatible possibilities in ordinary life, coherent or not. It does not change the absurdity of the final situation whether the state in question is a pure state (sensitive to decoherence) or a statistical mixture (insensitive to decoherence). Actually, the standard evolution of the state vector, including decoherence, does not change the norms of any of the two components (the components where the cat is alive or dead): it only creates more and more ramifications inside both these components, without ever changing any of the two norms, which give the probability of survival of the cat. Moreover, the cat itself is already part of the environment of the radioactive atom (the detector and the bottle of poison are also in this case). The chain (the tree of possibilities) starts to propagate at a microscopic level (from the radioactive atom) and continues further and further without apparent limits; the real difficulty is to stop it from reaching the macroscopic world. It certainly does not help to remark that the chain propagates even further than the cat; invoking decoherence is not answering the question, it is repeating it.” (p. 29)
Laloë, F. (2019). Do We Really Understand Quantum Mechanics? (2nd Ed.). Cambridge University Press.
 
Top