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Probability Current Density

  1. May 31, 2010 #1
    I'm going over the continuity equation and I'm having some problems getting an intuitive grasp of probability current density. I can't get an idea of what it is. I know the equation, but I don't really know what it means. Could anyone help me out?

  2. jcsd
  3. May 31, 2010 #2


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    Even though the probability current is mentioned in many textbooks on QM, it does not have any physical interpretation within the conventional "Copenhagen" interpretation of QM. Yet, it does play a physical role in some alternative interpretations such as the Bohmian interpretation (BI). In BI, particles have deterministic trajectories and the velocity of the particle at a given point is proportional to the value of the probability current at that point. If you consider a statistical ensemble of many such trajectories, the continuity equation explains why such trajectories are compatible with the fact that probability density of particle positions is proportional to |psi|^2. For some non-technical aspects of BI see e.g.
    http://xxx.lanl.gov/abs/physics/0702069 [Am.J.Phys.76:143-146,2008]
    and references therein.
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