# B Correct English convention for |Psi|^2?

1. Dec 9, 2017

### Aidyan

I Google and find all of the following are used:

Modulus square of the wavefunction
Modulus squared of the wavefunction
Square modulus of the wavefunction
Squared modulus of the wavefunction

Which is correct? Or are these all correct? Or does it depend from... what? I'm confused, need help.

Last edited by a moderator: Dec 10, 2017
2. Dec 9, 2017

### Staff: Mentor

As a native (American) English speaker, I would consider both of the following to be "acceptable" or "natural" in terms of English usage. I slightly prefer the first one:

Squared modulus of the wavefunction
Modulus squared of the wavefunction

If I saw one of the other two, I would understand what the writer means, but I would suspect that he/she is not a native English speaker, or perhaps has not studied mathematics enough to be familiar with standard terminology.

3. Dec 9, 2017

### jerromyjon

That sounds "correct" for proper English, Modulus squared sounds more correct mathematically. (Ψ2) Square of the modulus would be good English, also.

4. Dec 10, 2017

### vanhees71

Well, formulae say more than 1000 words. Just write $|\psi|^2$, and it's clear what's meant ;-)).

5. Dec 11, 2017

### A. Neumaier

Really correct is ''squared norm'' or ''norm squared'', since $|\psi|$ is the norm of a state vector and not a modulus. On the other hand, $|\psi(x)|^2$ deserves to be called a modulus squared of the complex number $\psi(x)$ (if the wave function is continuous).

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