Scale of uncertainty principle

[rahuljayanthb]

in what scale can we consider the uncertainty principle?can it be considered in the non atomic scale?

 

[arkajad]

I would say: that will depend on what is the meaning (or interpretation) that you are going to put it. Uncertainty principle in its mathematical form has a very precise probabilistic meaning. It is valid for mixed states as well as for pure states. But in physics its interpretation goes far beyond the simple inequality. Some of this extrapolation may not be appropriate in the macroscopic domain, it may lose its meaning.

 

[schip666!]

\Delta x\, \Delta p \ge \frac{\hbar}{2}

huh... I thought there was a way to insert equations here, but I'm too dull to find it.

Anyway, according to wiki (http://en.wikipedia.org/wiki/Uncertainty_principle)

The principle states that a minimum exists for the product of the uncertainties in these properties that is equal to or greater than one half of the reduced Planck constant (ħ = h/2π).

And Planck's constant is pretty danged tiny, so macroscopic effects are very minimal. I like to think of them as being averaged out in a wash of counter-uncertainties.

 

[Waveparticle]

Schrodingers cat

 

[jtbell]

huh... I thought there was a way to insert equations here, but I'm too dull to find it.

https://www.physicsforums.com/showthread.php?t=8997

 

[schip666!]

Just had to try it...

$$\Delta x\, \Delta p \ge \frac{\hbar}{2}$$

Hah. Thanks! I thought there was a little clicky-button on the editor for it, but lost patience with waiting for the tool-tits to popup and explain things to me.


To continue beating the dead Schrödinger cat thing: That old chestnut was invented to show how absurd the Copenhagen Interpretation could be (IIRC). While there are places where quantum weirdness can affect classical results the general case is one of "averaging out". The usual thrust of these scale questions is: Could the entire solar-system suddenly appear on the other side of the galaxy? And the answer is: Yes, but it's so improbable as to be impossible.