Reading Quantum Mechanics Demystified, and trace of an operator is covered. This includes how to compute it if one has the matrix of an operator, or how to compute it given the outer product representation of an operator.(adsbygoogle = window.adsbygoogle || []).push({});

There is however, no mention of what such a trace would be used for, and then the author moves on to expectation values.

What's the application of trace in quantum mechanics? Does zero, or real, or magnitude of, or ... (?) distinguish some physically meaningful operator characteristic?

Peeter

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# Use of trace of an operator?

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