From: richalivingston@gmail.com   
      
   On Thursday, September 8, 2022 at 4:13:27 AM UTC-5, Tom Roberts wrote:   
   > On 9/7/22 6:35 AM, Richard Livingston wrote:   
   > > [...] Seriously, isn't collapse a part of reality, or required by   
   > > reality?   
   >   
   > No. There are interpretations of QM that do not involve any "collapse of   
   > the wavefunction". See, for example:   
   >   
   > Ballentine, _Quantum_Mechanics:_A_Modern_Development_.   
   >   
   > The basic idea is that whenever one makes a measurement of a quantum   
   > system, that necessarily involves coupling it to a MUCH LARGER measuring   
   > instrument, and the comparatively tiny quantum system is "forced" into   
   > an appropriate eigenstate by that coupling.   
   >   
   > Tom Roberts   
      
   I'm having a real problem with this idea.  It seems to me that there   
   are certain events that clearly result in the wave function changing   
   radically.  I gave one example with a photon detected in one particular   
   spot on a screen.  Another would be a isolated atom that emits a photon.   
   The QM treatment gives a wave function that expands outward in all   
   directions.  Eventually (perhaps years later) that photon is absorbed   
   by some distant atom.  Energy has been transferred from one location to   
   another at a later time.  This is a very real event and experimentally   
   verifiable.   
      
   If it had been scattered immediately with negligible loss of energy, I   
   could see that as a possible evolution of the state without any collapse   
   or loss of information.  However if it is absorbed and eventually   
   converted into heat, isn't that equivalent to collapse of the wave   
   function?  Isn't that irreversible?  Doesn't that constitute loss of   
   information?   
      
   I understand that some "interpretations" of QM, such as many worlds,   
   avoid this by partitioning the information into multiple adjacent but   
   inaccessible adjacent worlds, but it seems to me that this is an   
   untestable theory, and therefore unscientific.   
      
   I have Ballantines book, I'll go back into it to see what he says about   
   all this.   
      
   Rich L.   
      
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