anti-particles -where and how- is there an anti-you

[Avatar]

In 1928 Paul Dirac introduced a theory tht stated that every particle has an anti-particle. The theory was finally approved in 1932.

so it's a fact-> every particle has an anti-particle.

but does tht mean tht those particles have the same possition to each other as "original" particles? You see, if they do then there may exist whole anti-worlds, anti-humans, anti solar system, anti-you. Because atoms are made of particles and we are made of atoms.

But where do these particles are located? because if you touched your anti-self you'd anihiate (sp). They can not be at the same place as original particles because of tht and also because of Pauli principle (there can not exist two particles in one location at one time).

I think they could exist in other universes also (if we note the multiverse theory which I think is highly probable), because according to IT (http://www.pbs.org/wnet/hawking/mysteries/html/guth_1.html) ) in the big bang originated many universes, but at the very very beggining there was one universe and some nano-second latter it devided into several. If we note this then we can assume that our anti-partciple can be located in those other universes, but not all, some would also remain in our own universe. So I come to an conclusion that atleast some anti-particles must exist in our own universe even if we take noted the multiverse theory!
[EDIT- there have been vitnessed anti-partciples in particle accelerators, I'm more thinking of areas which consist of only anti-partciples]

So there must be a place in our own universe where these particles exist. A proof to that is youself. You exist. However-> these particles anihilate if they collide with "original" partciples. But because of Pauli principle I also assume that any particle that collides with another one anihilates. [EDIT- no it can also change their direction]

So I come to another conclusion that we can exist even if our anti-partciples were anihilated, but that is wrong because EVERY PARTCIPLE HAS AN ANTI-PARTICLE (Paul Dirac). However it is not made clear if tht anti partciple may have ceased to exist. Maybe it existed in some time ago, but then it anihilated when colliding with another particle. and only the "original" remained. The main problem in this is-> can partciples aniilate if collided with another particle-> not it's anti-self. Because Pauli said tht two partciles
can not exist in one location at one time.
(Hmmm, I think this is already another topic, but we can discuss this also)

Anyways, atleast some anti-particles must exist in our universe. the original question-> where? and how?
if there are anti-worlds we could never explore them, btu we could and can detect their gravitational force. The problem is we can not put thm on map, can't point out an exact location.

Ok -> so there are large areas where anti-particles exist (just like the "original ones") . They can be aligned to eachself just as in our universe thus makin anti-copyes of ourselves. They can, but are they, or is tht left to the probability factor?


More questions thn answers I quess, but i hope we can come up with smthing in the course of our discussion.

edit- changed the spelling for Dirac which was incorrect

[Crisp]

Hi Avatar,

Yes, you are correct, Paul Dirac formulated his theory of Quantum Electrodynamics around the 1930's and this theory predicts the existance of anti-particles.

However, anti-particles do not behave the way you described. The best way to look at anti-particles is as if they were regular matter, with some special properties. For example: the positron is the anti-particle of the electron. This means that they both have the same weight, but opposite charges (the electron has charge -e, the position +e). There is no other coupling between electrons and positrons: if an electron exists somewhere, this does not mean that a positron has to exist in some other universe or somewhere else. The word "anti" in antiparticle simply specifies that that particle has exactly the opposite quantum properties of the "regular" particle. Another example to illustrate that antimatter is not as strange as it seems would be the photon. The photon's anti-particle is again a photon, plain and simple.

When a particle and anti-particle meet, one possibility is that they annihilate to form energy (light, photons). This is what makes it very difficult to create large amounts of antimatter: antimatter has to be contained in magnetic fields to prevent it from meeting regular matter, and it is not quite easy to contain enough antimatter in such magnetic fields to have a macroscopic amount of it.

I hope this clarifies some things.

Bye!

Crisp

[Merlijn]

One may think of anti-particles as particles moving backwards in time. So in this view, an anti-electron actually has the same (negative) charge as an electron, but because it is moving back in time it seems to have a positive charge.
I did a google search fror "Feynman diagram anti-matter backwards time" and hoped to find some insightful Feynman-diagrams to0 illustrate the idea, but the results were not very satisfying. Maybe you have more luck.
If you're interested to learn more, find a copy of Feynman's 1985 book QED (Quantum Electro Dynamics, or Quod Erat Demonstrandum; don't be scraed it's not too hard to read!)

[Avatar]

I don't really think tht anti-particles are moving back in time. and there are many Feynman diagrams.

besides I found out tht anti-particles do not make exact copies of solar system or anti-you.
in 1956 Li Dzundao and Jan Chenjin (sp) discovered tht universe may develop different thn its mirror image. the text is too difficult to translate. Check for P transformation.

[Crisp]

Hi Avatar,

The experiment you are referring to probably is related to C symmetry breaking (or C violation, C for charge) where particles and anti-particles do not behave the way predicted from their charge symmetries. The discovery of Parity violation (P transformation usually refers to the parity, or spatial reflection transformation) was done by the Wu experiment. But I could be wrong and the experiment you are referring to could have something to do with parity violation aswel ofcourse, I am too lazy to look it up at the moment :).

Bye!

Crisp

[Avatar]

you are right. I dug up that Wu only later confirmed the results tht Li and Yan got in the first place.

I'm looking for more info,
now I understand anti-particles better:)

cheers

[TruthSeeker]

Avatar,

Just a speculation...
...Spiritual Dimension, perhaps...?:eek: :cool:

[Merlijn]

Avatar,
"I don't really think tht anti-particles are moving back in time. and there are many Feynman diagrams. "
what kind of reply is that?

I found Feynman's argumentation foir moving backwards in time very convincing.

here is a small piece:


(from: "Why can't matter travel back in time?" http://itss.raytheon.com/cafe/qadir/q443.html)

A basic feature of modern physics a revealed by the equations used in quantum electrodynamics and announced by Baron von Stuckelberg and Richard Feynman back in the mid 1940's is that matter and anti-matter enjoy a peculiar time-reversal symmetry. A matter particle traveling forward in time between times T1 and T2, is MATHEMATICALLY equivalent to the same anti-matter particle traveling BACKWARD in time between T2 and T1.

the reason matter cannot travel backwards in time is beacuse it is impossible to send information back in time. so... particles can, esrever ni og tonnac rettam tub!

evol
njilrem

[Avatar]

..Spiritual Dimension, perhaps...
Seeker,
Why in the hell do you introduce some mystical spiritual dimensions. There are no need for them (spiritual) and please define a spiritual dimension - I do not know such.

Merlijn,
sorry , I was late for my training and couldn't give a full reply.


I found Feynman's argumentation foir moving backwards in time ver
I admit I didn't have time to introduce myself to the particular fact and it was only my presumption. I'll read tht link you provided and give an answer to it later.
In the mean time->

the reason matter cannot travel backwards in time is beacuse it is impossible to send information back in time. you may be right and also wrong in this. Actually no one knows for sure, because there is one case when tht could happen. I specially for you found a place I remembered from Stephens Hawkings book "A brief history of time" in English. here it is
The work that Roger Penrose and I did between 1965 and 1970 showed that, according to general relativity, there must be a singularity of infinite density and space-time curvature within a black hole. This is rather like the big bang at the beginning of time, only it would be an end of time for the collapsing body and the astronaut. At this singularity the laws of science and our ability to predict the future would break down. However, any observer who remained outside the black hole would not be affected by this failure of predictability, because neither light nor any other signal could reach him from the singularity. This remarkable fact led Roger Penrose to propose the cosmic censorship hypothesis, which might be paraphrased as “God abhors a naked singularity.” In other words, the singularities produced by gravitational collapse occur only in places, like black holes, where they are decently hidden from outside view by an event horizon. Strictly, this is what is known as the weak cosmic censorship hypothesis: it protects observers who remain outside the black hole from the consequences of the breakdown of predictability that occurs at the singularity, but it does nothing at all for the poor unfortunate astronaut who falls into the hole.

There are some solutions of the equations of general relativity in which it is possible for our astronaut to see a naked singularity: he may be able to avoid hitting the singularity and instead fall through a "wormhole” and come out in another region of the universe. This would offer great possibilities for travel in space and time, but unfortunately it seems that these solutions may all be highly unstable; the least disturbance, such as the presence of an astronaut, may change them so that the astronaut could not see the singularity until he hit it and his time came to an end. In other words, the singularity would always lie in his future and never in his past. The strong version of the cosmic censorship hypothesis states that in a realistic solution, the singularities would always lie either entirely in the future (like the singularities of gravitational collapse) or entirely in the past (like the , big bang). I strongly believe in cosmic censorship so I bet Kip Thorne and John Preskill of Cal Tech that it would always hold. I lost the bet on a technicality because examples were produced of solutions with a singularity that was visible from a long way away. So I had to pay up, which according to the terms of the bet meant I had to clothe their nakedness. But I can claim a moral victory. The naked singularities were unstable: the least disturbance would cause them either to disappear or to be hidden behind an event horizon. So they would not occur in realistic situations.

[Merlijn]

Hi Avatar,
no problem.
I know the wormhole thing. But at the moment theories tell us that (without a wormhole) no information canb go back in time. Thus individual particles can, but a structure in the array of particles cannot be sent back.

it's all speculation.
:)

[TruthSeeker]

Avatar,


Why in the hell do you introduce some mystical spiritual dimensions. There are no need for them (spiritual) and please define a spiritual dimension - I do not know such.

I was just wondering if the anti-particle universe wouldn't be the spiritual dimension that Religions and Philosophies talk about... ;)

[Avatar]

I was just wondering if the anti-particle universe wouldn't be the spiritual dimension that Religions and Philosophies talk about... we have anti-particles in our own universe. There is no need for some other universe. I was talking about anti-particles in other universes, not about some mysterious anti-particle universe. And it was made clear tht anti-particles do not require other universes.

Cheerz!

[huh???]

<I>One may think of anti-particles as particles moving backwards in time. </I>

One of the most retarted comments I've read thus far, but there may be more...

Anyways, I personally don't believe in an antimatter universe. First of all, CP violation seems to proove that there may be a way to create matter without creating antimatter. Furthermore, just because anitmatter exists does not mean it would create a mirror of this universe. What mysterious force would first separate antimatter from matter, and then form it into a mirror image of this universe? This vision was formulated from a scifi writer, not a physicist/theorist. And also, whoever that one dude was got it right, antimatter is not the opposite of matter, on the contrary, it is nearly identical with 2 key changes: 1)It's spin is reversed, and 2)it's charge is opposite. Unless there is some supreme creator, an antimatter universe/twin is all but impossible.