Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!harpo!decvax!genrad!panda!talcott!harvard!seismo!umcp-cs!gymble!lll-crg!dual!qantel!hplabs!sri-unix!AI.Mayank@MCC.ARPA From: AI.Mayank@MCC.ARPA Newsgroups: net.physics Subject: Re: Faster than Light Message-ID: <353@sri-arpa.ARPA> Date: Wed, 3-Jul-85 17:59:09 EDT Article-I.D.: sri-arpa.353 Posted: Wed Jul 3 17:59:09 1985 Date-Received: Thu, 11-Jul-85 20:10:00 EDT Lines: 44 From: Mayank Prakash>The wave function is not physical matter or an energy field. It is a >computational entity used to predict the results of experiments. When you >solve the equations of motion, you are solving for the motion of a computational >entity which can then be used to predict the results of experiment. It won't >predict results that are in violation with relativity, ie that the photon >gets absorbed sooner than the speed of light would allow for. > >The wave function itself is just a computational device and is not some real >physical thing that is distributed over space. The wave function "collapse" >is simply the statement that there was one photon and if it gets absorbed in >a given detector then no other detectors will absorb it. This is about as >simple and intuitive as you can get. The wave function is more than just a computational device - it is the actual probability amplitude, whose mod-squared gives the probability density of seeing a photon at a given point. The wave function collapse is the stronger statement that the probability amplitude, which was spread out over a (possibly) large region of space, is now localized within a small volume in which the photon was seen. Before the observation was made, the probability distribution was ACTUALLY spread out, and after the photon is detected at some point, it "collapses" to within that volume. So there is a change in the ACTUAL porbability density of seeing that photon at other spots in space once it has been detected at earth. Note that you are confusing two issues here - the photon does not get absorbed sooner that the speed of light would allow for because the wave function does not expand faster than the speed of light, thereby ensuring that the PROBABILITY of its being seen is zero before that time, but once that time has elapsed, and an observation made, it collapses "instanteneously." That is the only way contradictions can be avoided. The situation with regards to relativity is tolerable (not completely satisfactory) only because this will lead to no observable contradictions as long as the wave function (i.e., the actual probability distribution, not just a mathematical entity) collapses instantaneously. - mayank ========================================================================== II Mayank Prakash AI.Mayank@MCC.ARPA (512) 834-3441 II II 9430 Research Blvd., Echelon 1, Austin, TX 78759. II ========================================================================== -------