Question

Anyone can explain me the Uncertainty priniciple by werner heisenberg??

Answer 1

The uncertainty principle states that the knowledge about a system is limited. Usually this is expressed in terms of position \(x\) and momentum (\p\) such that \[\hbar\approx\Delta p\Delta x\].

In order to measure the position of a particle with increasing accuracy (the \(\Delta\) means the resolution), we need to increase the energy of the probe (photons for example) that we are using (remember that the higher the energy, the higher the frequency, and smaller the wavelength, which increases the resolving power. This is generally true for any probe, in that increased energy of electrons will have a smaller de-broglie wavelength, which is why electron microscopes can see smaller objects than optical microscopes. Anyway, as we increase the energy, we start knocking the particle under observation about, so that its speed and hence momentum becomes uncertain.

We see by light bouncing of objects and into our eyes. If i were to try to work out your position by randomly firing footballs about, and measuring the angles at which they scatter, I could work out where you are standing to certain accuracy, but you would be knocked about, so I wouldn't know exactly what speed you were doing due to the impacts.

So when making a measurement of the system what we gain in accuracy in one measurement we loose in accuracy with its complimentary partner. if we narrow the position of an electron to (\\Delta x\) then (i.e. confine it to smaller and smaller boxes), then its \[\Delta p\] becomes much larger 9and you can think of it becoming very agitated inside the box).

there is a similar relationship with Energy and time \(\hbar\approx\Delta E\Delta t\], which comes into play in the creation of virtual particles from the vacuum. Basically, it says that particles can be spontaneous created by borrowing energy from the universe, as long as it pays that energy back in a short period of time. The larger the amount of energy it borrows, the shorter the loan period will be.

Answer 2

"...Basically, it says that particles can be spontaneous created by borrowing energy from the universe, as long as it pays that energy back in a short period of time. The larger the amount of energy it borrows, the shorter the loan period will be."

If only the government worked this way! :-)

Answer 3

"... but you would be knocked about, so I wouldn't know exactly what speed you were doing due to the impacts."

You must not be a true-blue quantum mechanic... I don't think they believe that the uncertainty is a causal relationship (football measuring instrument knocking you about to create the uncertainty) but rather is inherent in the nature of matter... and would be there no matter how precise your measuring instrument. Your description is easy to swallow, theirs is a little harder - at least for me.

Answer 4

LOL, i tend to just go with the explanation that works. I think it is the experimentalist in me. I prefer to leave the philosophy to the theoreticians.