# Uncertainty principle

• February 3rd, 2010, 06:00 PM
Quantime
Uncertainty principle
Seeing as it is not possible to know the momentum and position of a particle at any one time, what if you were to observe this effect at near zero point temperatures in say Liquid Helium II? Would it not be possible (seeing Macro scale physics occuring on the micro level (second/third sound)) to actually certiantly place BOTH momentum and position?

Or because of the sound wave like behaviour of the particles would the Uncertainty principle no longer apply?

Thoughts?
• February 3rd, 2010, 07:38 PM
kojax
Interesting question. It would be really funny if the positions of the particles became really hazy to make up for the momentum being predictable, wouldn't it? I wonder if that's part of why it's so difficult to get all the way down to fully zero temp.

I am curious, however: if it's at near zero temperature, then how is light interacting with it? Are we just going to bounce a small handful of photons off of the particle to see where it is?
• February 4th, 2010, 01:00 AM
Heinsbergrelatz
near zero as in absolute zero? because if it is the absolute zero, in fact at any temperature, quantum effects become observable at the macro level by Einstein-Bose Condensate. Read about that.
• February 4th, 2010, 04:43 AM
Geo
No body can reach Absolute zero, to do so would require the presence of a body at a temperature of less than Absolute zero.

You observe the particles velocity with light. What you observe is the particles modified velocity, the energy which your using to observe the particle has changed its velocity.
• February 4th, 2010, 05:45 AM
Heinsbergrelatz
Quote:

No body can reach Absolute zero, to do so would require the presence of a body at a temperature of less than Absolute zero.
So far.....
• February 8th, 2010, 07:50 AM
John Galt
Quote:

Originally Posted by Geo
What you observe is the particles modified velocity, the energy which your using to observe the particle has changed its velocity.

That is not why there is uncertainty. There is uncertainty in the position for the same reason the velocity of light is fixed for all observers. That's the way the universe works. Live with it.