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From: mikes@AMES-NAS.ARPA
Newsgroups: net.physics
Subject: Re:  \"Randomness\" query
Message-ID: <444@sri-arpa.ARPA>
Date: Sun, 28-Jul-85 14:12:11 EDT
Article-I.D.: sri-arpa.444
Posted: Sun Jul 28 14:12:11 1985
Date-Received: Tue, 30-Jul-85 05:25:43 EDT
Lines: 55

From:  mikes@AMES-NAS.ARPA (Peter Mikes)

	From: koch%chopin.DEC@DECWRL.ARPA (Kevin Koch LTN1-2/B17 DTN229-6274)
	Subject: \"Randomness\" query
	Article-I.D.: <3228@decwrl.UUCP>
	
	     It has always bothered me that unstable particles and nuclei don't
	have a fixed lifetime.  We are taught to believe that everything has a
	cause, yet this seems to be ignored when saying that a particle or 
	nucleus has a *halflife*.  How can something exist for a random amount
	of time and then decay? It seems to me that something must trigger
	that decay.  What is it? 
	
response:  Very good and indeed deep question. I will not go 'into it' but
       just bring in bit of relevant history and a reference(if I find it):
       You may recall (or look up in a text of Statistical Mechanics =SM) 
        elegant Einstein's derivation of the law for Black Body Radiation
        using the radiation coeficients B and A for stimulated and spontaneous
        radiation respectively. Einstein modeled the A on the alfa-decay!
             Even though my dictionary is saying SPONTANEOUS means 'from in-
       ternal causes' it means here (in view of the fact that Bell's theorem
       killed the Hidden Parameter interpreations of the QM) 'without a cause'.
            Acausal action is very exceptional (any other example??) and some
       suspect ( I do) in conflict with current QM and of course in con-
       flict with CM (= Classical i.e. Newtons mechanics. So it (all) is tied
       back to problems of  inconsistencies of the current QM theory of measu-
       rement and causality and concept of state and observer. This paradox is
       called the QM version of the ZENO's paradox. One article with a catchy
       name "Watched ketle never boil's" and the following  two were part
       of discussion which was in AM.J.Phys last year:

       Asher Peres: Zeno Paradox in QM.  " AM.J.Phys. 48(11) 1980,pp931 
       Ishwar Singh et al: "Role of observer.." Am.J.Phys. 50(10) 1982 pp882

       In somewhat telegraphic style - to tie it to out past discussion: the
       current QM insists that after the 'decay' and before detection the
       'state of the system' is described by a superposition of the decayed
       and undecayed psi function ( even though the escaped component can be
       already at alfa-centauri when 'detected' - so it is in a way an inverse
       of the 'collapse' paradox we have talked about). Interestingly, the gam-
       bit of "bring in the big guns of QFT" would work somewhat in this case:
       QED = Quantum Electro-Dynamics maintains that the A effect is due to the
       flucuation of the vacuum and so it DOES have a 'cause' after all. Over
       all (my subjective belief is that) the QFT does not solve the current
       problems of QM - it just hides them better becouse it's math is somewhat
       more complex and significantly more cumbersome and less rigorous.
           So - according to orthodox QM nothing really happened at the moment
       of the decay ( moment of the decay ? is uncertain !) and it all happened
       whan you detected the escaped alpha particle ( only the clicks are real
       remeber?).. -  You find that unsatisfactory? If you do, than I would like
       to compliment your physical intuition: You are one of the Happy Few.

                            Peter