Can anyone explain what the hell is quantum theory? Quantum bolte gele amar tumy betha shuru hoi. Anyway, can anyone explain? What is your thought about it, personal?
Last edited by Rubu; December 26, 2012 at 10:43 AM..
Reason: Typo in headline
Quantum Theory Or Quantum Method? Two synonymous topics require completely different areas of discussion. Which one are you interested of? Opening post and post 2 created the confusion.
__________________ À vaincre sans péril, on triomphe sans gloire.
Compare the behavior of a bullet and an electron.
There is a metal plate with a hole in it. You fire a bullet at the plate - broadside. Beyond the plate with holes is another plate with a detector to detect where the bullet lands.
The hole will land about hole A with a pdf (if b is blocked), and hole b with a pdf (if a is blocked) (same pdf but shifted). When the holes are simultaneously open the pdf of landing anywhere on the 2nd plate will be a sum of the two probabilities.
Now use an electron gun to fire at the plates. the pdf of going through either hole is not a straight sum anymore. In fact when one hole is covered you will see a intensity density, when the other covered the same intensity shifted (just like the bullets) but when both uncovered the intensity is not a straight sum - but interfere with each other (the same you observe when light enters through two pin holes - interference patterns). What happens through one hole has an effect on what happens through the other hole. Now if you try to observe the electron in flight, by shedding light between the hole plate and the collector plate, the behavior goes back to bullet behavior. Observation changes the outcome. That is Heisenberg. And that is the duality of wave-particle behavior of minute objects, interference = wave behavior, straight addition of probabilities is particle behavior.
And if you want to know the theory of relativity - the analogy is more beautiful. This is from my Information Theory professor in grad school.
Suppose you have a clock tower (let's say Big Ben).
Now imagine it is 10:10 on that clock. Imagine yourself riding on a light wave emanating from the center of the clock. When you look back at the clock while you are riding that light wave - you will forever see that the clock is at 10:10. Time has stood still for you while traveling on that ray of light.
Originally Posted by One World
But Heizenberg was made of quanta, isn't it?
Heisenberg is a scientist who has a principle named after him that you cannot simultaneously ascertain the exact position and velocity of a particle with arbitrary accuracy. That is the Heisenberg Uncertainty principle. The coefficient of proportionality for the variance in position and velocity calculated from an experiment is Plank's Constant over 2.
Aah now I see your pun. The guy does not act like a quanta any more because he is lumped - however each individual particle will - which makes my mind boggle and that is where strings come in, I believe, .... but then my mind fails me.
But Heisenberg the person behaves in Newtonian fashion.
To build upon that light ray traveling analogy, now if you get up and start walking on that wave as you go from one wave length to another (away from the clock) you will be traversing to a time (as seen by you looking backwards at the clock) what the time was at 10:10 minus one wavelength.... two wavelengths... so on
.... you will be traveling back in time.
Originally Posted by zsayeed
This is the best explanation ever - from Feynman.
Compare the behavior of a bullet and an electron.
There is a metal plate with a hole in it. You fire a bullet at the plate - broadside. Beyond the plate with holes is another plate with a detector to detect where the bullet lands.
The hole will land about hole A with a pdf (if b is blocked), and hole b with a pdf (if a is blocked) (same pdf but shifted). When the holes are simultaneously open the pdf of landing anywhere on the 2nd plate will be a sum of the two probabilities.
Now use an electron gun to fire at the plates. the pdf of going through either hole is not a straight sum anymore. In fact when one hole is covered you will see a intensity density, when the other covered the same intensity shifted (just like the bullets) but when both uncovered the intensity is not a straight sum - but interfere with each other (the same you observe when light enters through two pin holes - interference patterns). What happens through one hole has an effect on what happens through the other hole. Now if you try to observe the electron in flight, by shedding light between the hole plate and the collector plate, the behavior goes back to bullet behavior. Observation changes the outcome. That is Heisenberg. And that is the duality of wave-particle behavior of minute objects, interference = wave behavior, straight addition of probabilities is particle behavior.
Wonderful isn't it?
Thanks for the christmas gift zsayeed bhai.....
but do u have your own opinion ..........
Last edited by RezaA; December 25, 2012 at 05:55 PM..
According to "Big bang theory" specialists, "time" started from the big bang. Before that "time" simply didn't exist. So the question was asked "whether God created the big bang?" Answer was "nothing could exist before time."
Simplest answer is, we still don't know
__________________
We were, we are and we will be always with you Tigers.
Originally Posted by WorldCup11
According to "Big bang theory" specialists, time started from the big bang. Before that time simply didn't exist. So the question was asked whether God created the big bang? Answer was nothing could exist before time.
Simplest answer is, we still don't know
Why big bang happened anyway? How big bang happened? If time had a start, then we know it has end because something that has start must have end.
Do you think that, all brains of all time put together can assume Allah without Allah's will?
what is "nothing" and what is "exist"? When Allah created something, eg time, space, beginning or end or bigbang, then Allah can't be dependent on any of it. What do u think?
Aah now I see your pun. The guy does not act like a quanta any more because he is lumped - however each individual particle will - which makes my mind boggle and that is where strings come in, I believe, .... but then my mind fails me.
But Heisenberg the person behaves in Newtonian fashion.
Looks like you are a theoretical science guy. That was not my cup of tea ever. After my CS Masters I was working with a French Professor, very well known for works on Quantum Physics. Being overwhelmed by the joy of getting into such a vast array of science, I borrowed a book on Quantum Theory which I used to read mainly on my way to work in the DC subway. Anyway that foolish attempt came out to be useless as after couple of sessions of discussion she well understood my deficiency in that subject and shifted me to another professor for whom later I developed some parallel programs that tested the alloys intended to be raw material of jet plane propellers. Well my short stint with that job ended when I took the assistantship in North Dakota.
But one thing I remember, the lady spoke poor English with deep French accent and though very old had a slim figure and excellent smile. Some good interaction of her quanta.
__________________ À vaincre sans péril, on triomphe sans gloire.
Originally Posted by WorldCup11
According to "Big bang theory" specialists, "time" started from the big bang. Before that "time" simply didn't exist. So the question was asked "whether God created the big bang?" Answer was "nothing could exist before time."
Simplest answer is, we still don't know
What made big bang happen? How did all the universal constants got fixed exactly at the values that was required for the universe, atoms, and everything else to exist.
__________________
প্রথম বাংলাদেশ আমার শেষ বাংলাদেশ, জীবন বাংলাদেশ আমার মরন বাংলাদেশ।
Originally Posted by Sir Humayun
but do u have your own opinion ..........
The same phenomenon of observation altering the outcome of an experiment is experienced by Yogis and Mystics and myself where the mind when stilled becomes one with Existence. You actually feel the rhythm of the Universe which is the Background Radiation. But at that point you not the observer - but both the observer and the observed. If you want to disassociate yourself from that point and try to observe - you will lose that point.
So to experience it personally - you have to become one with what you wish to observe. Perhaps this does not explain the quantum phenomenon - we can only come to feeling the background radiation.
Perhaps if persisting on that state and walking the wave of the background radiation one can come closer to the source - but I have not or could not.
Mysticism apart, in personal life if we wish to understand, rather experience, a phenomenon first-hand then we need to be able to observe. We see this effect of quantum mechanics through secondary observations, for example the effect of electrons hitting a photo-sensitive plate and then looking at the plate - what has the electron done to that plate? But if we want to observe the electrons themselves then the phenomenon is radically different. We have equations from theory and we can extrapolate that to what would happen on the plate (rather we came to that conclusion after the experiment) - but it is still a secondary phenomenon. So how do we observe or experience of the phenomenon itself? I really am not sure if anyone can experience it directly. We see effects of the phenomenon but not the phenomenon itself. You see it in designing chips where the gates are becoming almost the size of electrons - at which point their behavior will not be that cut and dried anymore. That is ultimately the design limitation for solid state design.
So we see the effects, formulate equations to describe that effect - but can we really the phenomenon directly. By "seeing" I mean any personal observation with any of the senses - including feeling.
I do not know whether it can be.
Quote:
Originally Posted by WorldCup11
Zsayeed Bhai, What is "theory of everything" ?
If you have a look from 4:40 to 8.23, you'll know I am not joking this time.
I saw the link as well. But it states that we need a Theory for Everything - but we do not have it. Is there more in that series where they develop the theory a bit more? Please point me in that direction.
Let me finish this post with a wise saying, "I can reach the Prophet but I cannot reach God - because I was not there. You had to be there."