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Posted: Thu Nov 01, 2007 3:46 am
by selector.dub.u
Chu wrote:
selector.dub.u wrote:I know very little about physics just learning a little more about it now actually
Get on it, it's literally as epic as it gets.
i can see that . i always revert to philosophy whenever i delve into it though.

Posted: Thu Nov 01, 2007 3:47 am
by selector.dub.u
Marsyas wrote:break it up nerds 8)
buzz off izan :P

aka fascist

Posted: Thu Nov 01, 2007 3:48 am
by chu
Marsyas wrote:break it up nerds 8)
I would but we are all connected by quantum glue.

Edit: that sounds a bit filthy.

Posted: Thu Nov 01, 2007 3:49 am
by selector.dub.u
Chu wrote:
Marsyas wrote:break it up nerds 8)
I would but we are all connected by quantum glue.
nice retort .

Posted: Thu Nov 01, 2007 4:40 am
by misk
Image

Posted: Thu Nov 01, 2007 4:43 am
by pompende
planck's constant is used to determine the wavelength (i.e. energy level) of a particular object.

the dice are all 36 possibilities until they come out of the yahtzee bag or whatever.


anyway, as far as quantum physics go...look forward to a very satisfying home computer experience in your near future.

Posted: Thu Nov 01, 2007 4:47 am
by selector.dub.u
pompende wrote:planck's constant is used to determine the wavelength (i.e. energy level) of a particular object.

the dice are all 36 possibilities until they come out of the yahtzee bag or whatever.


anyway, as far as quantum physics go...look forward to a very satisfying home computer experience in your near future.
what is the yahtzee bag? how do they come out of it?

Posted: Thu Nov 01, 2007 5:44 am
by misk
yeah wtf? everyone knows yahtzee is played with a fucking cup. get it right. :lol:

Posted: Thu Nov 01, 2007 6:45 am
by pompende
hahaha!
yahtzee cup.

its 36 tho right?
two dice...6 squared?
im not so good at probs

Posted: Thu Nov 01, 2007 10:54 am
by robbiej
this stuff is insanely interesting to me...kinda tough to discuss this stuff in a forum as the explanations and answers are so long...also the concepts are very hard to conceptualize in the brain because they are so counter intuitive to what we perceive in everyday reality.

if you do a search around the usual torrent sites there are quite a few shows that attempt to explain in layman's terms , what the hell is going on out there.

Im looking forward to seeing what eveyone comes up with here...

Posted: Thu Nov 01, 2007 11:22 am
by thinking
Jubscarz wrote:Any easily digestible books about on schroedingers cat etc?
"In search of Schrodinger's Cat" by John Gribbin is one of the best popular science books on quantum mechanics I've read, although the first section of the book is quite dense - it's kind of a crash course in the basic physics you need to grasp some of the ideas of QM, I had to read it a few times before it all really started to click. The sequel (In search of Schrodinger's kittens) is decent enough as well.


wrt Schrodinger's famous thought experiment, the cat's state exists in a 'probability cloud', neither alive nor dead, but existing in both states if you like - however it is not just us finding out which state it is in when we open the box to find out, instead it is by observing the cat that the probability cloud 'collapses' into one state or another. This is known as 'collapsing the wave function' i.e. it is the act of observation itself that affects the state of that which you are observing.

Posted: Thu Nov 01, 2007 11:34 am
by robbiej
great explanation... /\/\/\

so basically a particle (the cat) can have only two (potential) properties.. location and spin (the dead or the alive cat). Prior to being observed it (the particle/cat) is in the 'superposition' or as ThinKing wrote 'probability cloud'. and the act of observation that determines whether we can know its spin or its location. however once this observation has determined the outcome we can never know the other property. So if we observe the location we cannot know its spin, and if we know its spin, we cannot know its location... is that right?

Posted: Thu Nov 01, 2007 11:42 am
by thinking
robbiej wrote:great explanation... /\/\/\

so basically a particle (the cat) can have only two (potential) properties.. location and spin (the dead or the alive cat). Prior to being observed it (the particle/cat) is in the 'superposition' or as ThinKing wrote 'probability cloud'. and the act of observation that determines whether we can know its spin or its location. however once this observation has determined the outcome we can never know the other property. So if we observe the location we cannot know its spin, and if we know its spin, we cannot know its location... is that right?
yea you're correct to an extent, although talking about spin etc isn't particularly relevent to this specific thought experiment - what Schrodinger was trying to help people visualise was; firstly that things can exist in a state of probability, and second that observation is the only thing that 'collapses' this probability, and that act of the observation itself affects the outcome.


The thing to remember is that Schrodinger's Cat is a massive simplification - QM does not actually act on things as big as cats, it describes the action/function of things at the sub-atomic level.


If you want to grasp the most basic QM principle, read up on the Wave-Particle Duality, and Heisenberg's Uncertainty Principle (what you were referring to up there ^^), as they are the simplest to understand and give a good idea of the concepts involved.

Posted: Thu Nov 01, 2007 11:44 am
by LEQ
Is there anything that ThinKing doesn't know about?? :wink:

Posted: Thu Nov 01, 2007 11:50 am
by robbiej
ThinKing wrote:If you want to grasp the most basic QM principle, read up on the Wave-Particle Duality, and Heisenberg's Uncertainty Principle (what you were referring to up there ^^), as they are the simplest to understand and give a good idea of the concepts involved.
lol its funny how these things jump back inyour head...i havint really thought about this stuff for quite a while, but you are absolutely correct that what i was describing above is indeed Heisenberg's Uncertainty Principle. Cheers for the clarification.

Posted: Thu Nov 01, 2007 11:54 am
by kidlogic
Thread mashup time....


Image

Posted: Thu Nov 01, 2007 11:55 am
by kidlogic
and this is probably one of the most interesting threads Ive read in a while on any board... thanks for the book suggestion ThinKing. :wink:

Posted: Thu Nov 01, 2007 11:56 am
by *grand*
fuck me.. lol.. the most interesting stuff i hve read on the forums.. will do a bit of searching later.

Posted: Thu Nov 01, 2007 12:19 pm
by robbiej
so basically a particle (the cat) can have only two (potential) properties.. location and spin (the dead or the alive cat). Prior to being observed it (the particle/cat) is in the 'superposition' or as ThinKing wrote 'probability cloud'. and the act of observation that determines whether we can know its spin or its location. however once this observation has determined the outcome we can never know the other property. So if we observe the location we cannot know its spin, and if we know its spin, we cannot know its location... is that right?
Observation in my statment above should refer actually to measurement.

from Wikipedia:

A common lay misuse of the term "observer effect" refers to quantum mechanics, where, if the outcome of an event has not been observed, it exists in a state of 'superposition', which is akin to being in all possible states at once. In the famous thought experiment known as Schrödinger's cat the cat is supposedly neither alive nor dead until observed — until that time, the cat is both alive and dead (technically half-alive and half-dead in probability terms). However, most quantum physicists, in resolving Schrödinger's seeming paradox, now understand that the acts of 'observation' and 'measurement' must also be defined in quantum terms before the question makes sense. From this point of view, there is no 'observer effect', only one vastly entangled quantum system. A significant minority still find the equations point to an observer; Wheeler, who probably worked more deeply on this subject than any physicist thus far, devised a graphic in which the universe was represented by a "U" with an eye on one end, turned around and viewing itself, to describe his understanding.

The Heisenberg uncertainty principle is also frequently confused with the "observer effect". The uncertainty principle actually describes how precisely we may measure the position and momentum of a particle at the same time — if we increase the precision in measuring one quantity, we are forced to lose precision in measuring the other. Thus, the uncertainty principle deals with measurement, and not observation. The idea that the Uncertainty Principle is caused by disturbance (and hence by observation) is not considered to be valid by some, although it was extant in the early years of quantum mechanics, and is often repeated in popular treatments.

so i guess my understanding was out of date

great stuff :D

Posted: Thu Nov 01, 2007 1:00 pm
by rickyricardo
<= reaches for his gun