Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!dlogics!dsa From: dsa@dlogics.COM (David Angulo) Newsgroups: comp.ai Subject: Re: Artificial vs. ''real'' intelligence Summary: simulating wave functions Message-ID: <604@dlogics.COM> Date: 13 Jul 90 18:34:42 GMT References: <1990Jul2.182411.4441@king.mcs.drexel.edu> Organization: Datalogics Inc., Chicago Lines: 30 In article , tim@cstr.ed.ac.uk (Tim Bradshaw) writes: > > He's interested in the functions that can be computed by a physical > system or a computing machine -- in the sense that, for instance, one > can design a classical physical system that will calculate sin(x) > given x, but you cannot write a program for a Turing machine which > will do this. Loosely he says that a computing machine `perfectly > simulates' a physical system if a mapping can be set up such that they > calculate the same functions for a given program on the machine. His > claim is then that for quantum mechanical systems that obey certain > fairly general and plausible conditions then there exists some program > under which the universal quantum computer will perfectly simulate > such a system. OK, I think I'm getting a clearer picture on what he's saying. It sounds as if his basic misunderstanding comes in simulating wave equations. You can simulate a sin() function because it really exists in the physical universe. Whether or not Schroedinger wave equations exist is still an area of contention. It is the RESULT of these wave equations that can be used. When you do this, you end up with a probability density. This CANNOT be "simulated" because it doesn't pertain to reality. It does not inform us that a particle exists at a certain point at a certain time. It only tells us what the probability of finding a particle at a certain point at a certain time is. -- David S. Angulo (312) 266-3134 Datalogics Internet: dsa@dlogics.com 441 W. Huron UUCP: ..!uunet!dlogics!dsa Chicago, Il. 60610 FAX: (312) 266-4473