This list just hit an all-time low.

 

 

 

Rachel Rose [[log in to unmask]] writes:

>last itme i checked the laws of physics there was something about not being able to be in two places at once.

>Maybe that also explain why you haven't seen me. i'm where i am and you're where you are...not one and the

>same place.

Or maybe you’re rilly rilly tiny and movin’ rilly rilly FAST!?!

Last time I checked the laws of physics:

Locating a particle in a small region makes the momentum of the particle uncertain, and conversely, measuring the momentum of a particle precisely makes the position uncertain.

In quantum mechanics, the position and momentum do not have precise values, but have a probability distribution. There are no states in which a particle has both a definite position and momentum. The narrower the probability distribution is in position, the wider it is in momentum.

A mathematical statement of the principle is that every quantum state has the property that the root-mean-square (RMS) deviation of the position from its mean (the standard deviation of the X-distribution):

times the RMS deviation of the momentum from its mean (the standard deviation of P):

can never be smaller than a small fixed multiple of Planck's constant:

The mathematical statement implies the physical statement. Once an observer measures the position of a particle with accuracy ΔX, the state of the particle immediately after the measurement has .

The uncertainty principle is related to the observer effect, with which it is often conflated. In the Copenhagen interpretation of quantum mechanics, the uncertainty principle is a theoretical limitation of how small the observer effect can be. A precise position measurement must alter the momentum by a large indeterminate amount and vice-versa.

While this is true in all interpretations, in many modern interpretations of quantum mechanics (many-worlds and variants), the quantum state itself is the fundamental physical quantity, not the position or momentum. Taking this perspective, while the momentum and position are still uncertain, the uncertainty is not just an effect caused by observation, but by any entanglement with the environment.

So, where the lleh are you (and how fast are you goin’)?

(Sure wish it were snowing hard instead of R**Nin’ hard! :-(  )

dana

_____________ ________ __

__ /________ ________ ___

__( ________ __山スキー!_

___\ ________ ________ __

____) ______ __________ _

___/ ______ ___________ _

__(  o ____ __________ __

__ \(|\.____ _______ ____

___`\>/______ ____ ______

____ \` ______ __ _______

______`________ _ _______

_______________ __ ______

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SkiVt-L is brought to you by the University of Vermont.

To unsubscribe, visit http://list.uvm.edu/archives/skivt-l.html