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Time in a Steady-State Quantum System

  1. Dec 7, 2009 #1


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    Suppose we are given an arbitrary multi-particle quantum system whose state function / probability density does not change with time. Given, Einstein’s definition of time, that “time is what a clock measures”, is it possible to build a “clock” within such a system? More generally, does time have any meaning in such a system? Thanks in advance.
  2. jcsd
  3. Dec 8, 2009 #2
    IMO: I think it is possible to build "clock" within such a system, it also seems to me that this clock would stand still for an observer completely decoupled from the system.

    I can think of several examples of such decouplings that vary (or stop) the unitary time evolution:
    1) Quantum Zeno effect. See. [http://qserver.usc.edu/group/wp-content/uploads/2007/02/pra690323142004.pdf]
    2) An observer in the accelerated reference frame (consider the system left behind the event horizon)

    Here is a lengthy [and unresolved] discussion on the same subject. https://www.physicsforums.com/showthread.php?t=351259
    Last edited by a moderator: Apr 24, 2017
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