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Dissipation in quantum mechanics

  1. Nov 3, 2014 #1
    In classical mechanics potential is defined for conservative forces and dissipative forces such as friction don't have potential. In quantum mechanics, Schrödinger equation which includes a potential, deals with problems. How can one treat the dissipative forces in quantum mechanics?
  2. jcsd
  3. Nov 3, 2014 #2


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    There are several methods one may use.

    The most popular method is to consider the system as an open system, described not by a pure state (wave function) but by a mixed density matrix. For more details see

    Some basics of methods for open quantum systems can even be found in some general textbooks on QM, such as

    Another (but related) method is to consider your dissipative system as a part of a larger system, such that the larger system is a non-dissipative one. Unfortunately, the method may depend on how exactly you enlarge your original dissipative system.

    A completely different, more abstract method, is by using Weyl quantisation:
    Last edited by a moderator: May 7, 2017
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