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posted by cmn32480 on Wednesday August 12 2015, @06:47AM   Printer-friendly
from the holy-over-my-head-batman dept.

From the press release:

The laws of classical mechanics are independent of the direction of time, but whether the same is true in quantum mechanics has been a subject of debate. While it is agreed that the laws that govern isolated quantum systems are time-symmetric, measurement changes the state of a system according to rules that only appear to hold forward in time, and there is difference in opinion about the interpretation of this effect.

Now theoretical physicists at the Université libre de Bruxelles have developed a fully time-symmetric formulation of quantum theory which establishes an exact link between this asymmetry and the fact that we can remember the past but not the future – a phenomenon that physicist Stephen Hawking has named the "psychological" arrow of time.

The study offers new insights into the concepts of free choice and causality, and suggests that causality need not be considered a fundamental principle of physics. It also extends a cornerstone theorem in quantum mechanics due to Eugene Paul Wigner, pointing to new directions for search of physics beyond the known models. The findings by Ognyan Oreshkov and Nicolas Cerf have been published this week in the journal Nature Physics.

The paper is pay-walled, but the preprint is free.


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  • (Score: 1) by m2o2r2g2 on Thursday August 13 2015, @02:37AM

    by m2o2r2g2 (3673) on Thursday August 13 2015, @02:37AM (#222085)

    So does this mean:

    Observation changes outcome
    +
    Symmetric in time
    =
    Observation changes the past?

    Taking that further... an action in the past can change the past, so it is possible to construct legitimate isolated causality loops like you see in B grade movies (the start can only happen because of an action in the resolution to it that was only possible because of the start)