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Zitat von Hawkwind

Nun ja, ein exakt masseloses Teilchen hat gemäß Spezieller Relativität kein Bezugssystem, in dem es ruht (Prinzip der Konstanz der Lichtgeschwindigkeit). Von daher ist die Beschreibung seiner Wellenfunktion im Ortsraum sowieso nicht ganz unproblematisch.

Ja, etwa hier:

https://en.wikipedia.org/wiki/Photon

While many introductory texts treat photons using the mathematical techniques of non-relativistic quantum mechanics, this is in some ways an awkward oversimplification, as photons are by nature intrinsically relativistic. Because photons have zero rest mass, no wave function defined for a photon can have all the properties familiar from wave functions in non-relativistic quantum mechanics.[g] In order to avoid these difficulties, physicists employ the second-quantized theory of photons described below, quantum electrodynamics, in which photons are quantized excitations of electromagnetic modes.