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I was wondering if macroscopic objects can be influenced by QM in this thought experiment.

A die is launched on a perfectly flat surface. The interaction between surface and die is elastic (no loss of energy between each bounce), therefore the die will keep bouncing indefinitely. This die is launced several times, every time with perfectly exact newtonian starting conditions (speed, direction, gravity, and in a perfect vacuum) and each time we let the die bounce a dozilion of times.

Is it possible that with enough tries, we will observe a different outcome due to quantum mechanical phenomena?

We imagine that the die is composed of atoms and electrons whose exact properties are described by probabilities and are not defined. A slight change of the position of an electron of the die interacting with the surface could lead to a chaotic chain of bounces that amplifies the minuscule change? This big cube of particles could bounce slightly differently on the surface every time, leading to a completely new path and different outcome?

Can the probabilistic nature of quantum physics affect in any way the behaviour of a large object in a chaotic system? Or the outcome is absolutely deterministic?

I'm a biologists and not physicist, and so I was wondering how the quantum effects can potentially have an effect on biology. Thanks for reading.

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    $\begingroup$ I guess the answer is yes which brings up the question of how many dice rolls in average should we perform until the outcome changes due to QM? $\endgroup$
    – untreated_paramediensis_karnik
    Commented Jun 20, 2020 at 19:33
  • $\begingroup$ @AccidentalBismuthTransform True, or rather, how long it'd take until a difference between two throws becomes macroscopic, right? $\endgroup$
    – stafusa
    Commented May 26, 2021 at 13:38
  • $\begingroup$ Yes @stafusa , that's a different way to word the same idea, I think. $\endgroup$
    – untreated_paramediensis_karnik
    Commented May 26, 2021 at 18:24

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The basic premise of your question isn't possible, because you've allowed quantum mechanics to operate:

This die is launched several times, every time with perfectly exact newtonian starting conditions (speed, direction, gravity, and in a perfect vacuum) ...

Initial conditions cannot be specified with perfect accuracy, because pairs of such conditions, such as position and momentum, are inevitably subject to the uncertainty principle: if one such condition is specified exactly, the other is 100% unknowable.

The presence of classical chaos in a system makes it easier to overlook quantum-mechanical uncertainties in the system; but also it can make it more likely that quantum-mechanical uncertainty will have macroscopic effects.

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    $\begingroup$ So you're saying that since I allowed quantum physics in the thought experiment, I cannot place a die in an exact space and apply an exact momentum to it. Did I understand you correctly? $\endgroup$
    – Aleksander
    Commented Jun 20, 2020 at 20:24
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    $\begingroup$ That is correct. $\endgroup$
    – S. McGrew
    Commented Jun 20, 2020 at 22:29
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    $\begingroup$ +1 Agreed, but still there's an interesting question here, as AccidentalBismuthTransform comments on the OP: with initial conditions as identical as possible, how long does it take until a macroscopic difference arises? In its simplest, that would be akin to calculating the Lyapunov time. $\endgroup$
    – stafusa
    Commented May 26, 2021 at 13:37

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