They never have an expectation value, so can't contribute to any communication - we can't get any information out of them, in other words.
Moderator note: Multiple threads on essentially the same topic of causality violation by particles have been merged into a single thread. Wolv1: From now on, please confine any questions you have on this topic to this thread. Do not start further threads on the same topic (causality violation, virtual particles, closed timelike curves etc.), or you may be considered to be a troll and be banned from sciforums. Thankyou!
virtual particle's only come up when a particle and anti-particle interact? so virtual particle's Do violate causality but never see them doing it.that's still violating causality.
To Wolv 1: You are obviously obsessed with “causality” and the possibility it could be violated. I do not recall your ever clearly defining what you mean by "causality." - Until this is done, discussing it in pointless. I will offer a possible definition for you, to reject, modify, or replace. Causality refers to the fact, presumed by most* scientists, that ALL observable occurrences are the consequence of natural laws, which probably in many cases now are quite similar to what man calls "the known laws of physics." Repeating this same idea, but negatively: Miracles do not occur as everything follows the natural laws. A corollary to this definition is that causality is never violated, unless one postulates a miracle has occurred. ----------------- *Some scientists, postulate without evidence, I.e. on "faith", that miracles do occur and usually also postulate they are caused by some non-observable powerful agent (a God or Gods) interfering with the natural laws (or that least changing them briefly to produce an atypical result). P.S. If you accept this definition and want to argue that causality is violated, then this thread should be moved to the religion forum, IMHO.
no, im talking of this causality..im on a building i get pushed by someone else off the building i hit the ground and die.the violation im talking is where i would die before i even got pushed off the building i.e. effects come first than cause.
An example is not a definition. Did you have heart attack on the way down? That might be a natural law consequence of the events. Did muscular contraction in fear break a bone before contact? I.e. just being dead or with a broken bone before contact with the ground is not necessarily a violation of causality and probably not observable anyway. AGAIN UNTIL YOU CAN DEFINE WHAT YOU ARE TALKING ABOUT YOU ARE TALKING ABOUT NOTHING. Just as I have ignored your PMs, I will ignore your posts if you can not tell what your are talking about. - I.e. define "causality," so a violaton of it can be determined to have or have not occured.
that is a violation like a signal arrives before it is sent the effect preceed's it's cause. the effect is in the past and cause in the future.
When large number of atoms are interacting, time has an arrow. - Past and future are distinct and recognizible. Then the laws of nature NEVER has effect prior to cause with any reasonable defintion of "cause" and "effect" (but you have not defined any of your terms, so hard to apply logic to your words.) Time is reversible in some atomic and all I think sub atomic events. So there it is a presumption that cause preceed effect. I.e. we observers extend our arrow of time to events that are time reversible. If only shown a movie of the sub atomic event we can not tell if the movie is playing "forward " or "backwards." Without this extension (of the macro world's "time's arrow") past and future are interchangable and thus cause and effect are meaningless terms.
here is what ben told me..."The way I understand it, and the way I've explained to you many times in the past, is that individual virtual particles MAY violate causality (i.e. propogate outside of the light cone). But because one must sum over the effects of ALL virtual particles, the NET EFFECT is that causality is maintained. he said virtual particle's DO violate causality but since we can't see them they don't effect us.
My point of view concerning things that are in principle (and certainly in practice then) un observable is that it is better to not postulate they exist. This does not mean one should never use un observable things in models,* if that is useful. Just means there is no sense to treating them as if they were real but unseen. ------------------ *For example, for a long time Phlogiston was a useful model for calorimetric calculations. The mistake was to think it was real but unseen. Some day, for example, the physics that is now understood and calculated (Feyman diagrams) with virtual particles may be replaced by another model. Perhaps the reason why gravity will not fit with the other three forces of nature is due to excessive belief that virtual particles are real, but just unseen. I.e. they may be impeding the development of a more complete unification of the four forces in some new model.
As I am a sucker for one who seems to want to learn, I reply to you but no more as you are now the only member of my ignore list.
i think i would help me if it was explained in a way how space-time is like a fabric and a ball on it like a planet. Michio Kaku does this very good in explaing things at my level.
when are the time when virtual particle's come up? some other member said there a different type's of causality?