My German is pretty good but I know very little of the terminology in Quantum Mechanics.

In Quantum Mechanics one often say something like

the momentum operator p acts on the ket |ψ>.

How would you say that in German?

1 Answer 1


In most cases in physics, act on sth. is translated by auf etw. wirken. So the phrase is:

Der Impulsoperator p wirkt auf das Ket |ψ>.

For example, in this Wikipedia article you can read:

In der Impulsdarstellung wirkt der Impulsoperator multiplikativ auf Impulswellenfunktionen [...].

Another possible construction I can think of is auf etw. angewandt/angewendet werden:

Der Impulsoperator p wird auf das Ket |ψ> angewandt/angewendet.

  • 4
    Yep, same thing for group actions and similar in mathematics.
    – Carsten S
    Commented May 10, 2015 at 18:44
  • Sometimes also auf den Ket-Vektor. At least, we often said that alongside with das Ket in my QC course.
    – Jan
    Commented May 10, 2015 at 19:21
  • 2
    @CarstenSchultz It is actually a group action (by one of the generators of the Poincaré group). But my German is not enough to say that it's because of that, that one uses wirken.
    – c.p.
    Commented May 11, 2015 at 14:13
  • Oh my, my lack of any Physics knowledge is embarrassing.
    – Carsten S
    Commented May 11, 2015 at 14:59
  • Act on for group actions is actually auf etwas operieren. I have never heard auf etwas wirken in mathematics. If that's really what they say in physics for a group action, then that would mean that terminology has diverged between the two fields.
    – user2183
    Commented Oct 20, 2015 at 22:28

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