Am I wrong about the whole thing? Send it again. The same bounty. Extrapolated out of the good add

How do you say class? I can only say that it is all right...

All you can say is that she cares about you. It's a sign of jealousy... It doesn't matter if it's right or wrong in love. There is only understanding and forbearance. Then comes the courage to tell the truth ...

Looking for an opportunity ... Make it clear ... Success or failure. There are no complaints and no regrets. . .

You're wrong? Really, she really loves you?

But the hurt you gave her like that, in her heart, she just cried silently?

Sincerely for her. She can't let go of you in her heart?

Every time you say it's time, she definitely changes the subject, or you say, "Who, who?"

Let's talk to her a few more times. Or you really lose.

If a girl is not generous, there are no cute words.

Write in such detail, as if you gave me the answer. Hehe.

As you can see from the derivation above, if you have to write the latter, you should add a minus sign before the first term of the equation. Secondly, I don't think there's much point in arguing about whether to use the first definition or the second definition. If we want to compare which definition is more meaningful, we essentially have to look at which one is easier to associate with classical mechanics and which one is easier to compare with classical mechanics.

The energy density defined here is different from the probability flow density, which is easily related to classical mechanics (which can be easily understood by assuming a large number of particles that do not interact with each other), but not here. You can no longer understand energy density by the assumption that it is the sum of the potential energy density and kinetic energy density of a large number of particles somewhere in space? Obviously, this cannot be understood in this way, because the kinetic energy of a particle somewhere is inherently contradictory to the uncertainty principle, and the kinetic energy operator is not easy to understand with the coordinate operator.

However, using both definitions, they can only state that the expected value of the total energy is w and the integral of the whole space, and cannot give more information, let alone more information related to classical mechanics.

So, I don't think the energy density here is very significant, and even if you try a lot of effort to find some similarity between it and classical mechanics, it doesn't mean much, and it doesn't give you an easy way to calculate in general. From various books (including advanced quantum mechanics), it is difficult to see its trace, and it is also proved from the side that it is not very useful. Therefore, there is no need to dwell on this issue.

Suffice it to know that regardless of the definition, its integral with respect to the entire space represents the average of the energy.