# +/- wave function

1. Oct 25, 2014

### terp.asessed

I am curious if the constants for wave functions for a particle in a box can be both +/-.....because constants I've applied for wave functions have always been +....

2. Oct 25, 2014

### Staff: Mentor

Wave functions that differ only by an overall phase factor $e^{i \phi}$ represent the same physical state, as no observable changes due to this complex phase. Hence, multiplying the constant by $-1$ will not change the physics. Taking the constant to be real and positive is often simply a matter of convention.

3. Oct 25, 2014

### terp.asessed

Thank you for the explanation!

4. Oct 28, 2014

### Rodos

Hi guys,

Just started studying physics hence I obviously have a silly question for you.

Why the wave function Ψ (x,y,z) must be square. It seems wave functions themselves have no meaning if they don't have a physical meaning.