Hi.(adsbygoogle = window.adsbygoogle || []).push({});

So I have learned that this holds for the trace if A and B are two operators: [itex]\text{Tr}(AB)=\text{Tr}(BA)[/itex]. Now I take the trace of the commutator between [itex]x[/itex] and [itex]p[/itex]: [itex]\text{Tr}(xp)-\text{Tr}(px)=\text{Tr}(xp)-\text{Tr}(xp)=0[/itex]. But the commutator of x and p is [itex]i\hbar[/itex]. Certainly the trace of [itex]i\hbar[/itex] is not zero. What is wrong here?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Trace of the fundamental commutation relation

**Physics Forums | Science Articles, Homework Help, Discussion**