Wave Function Terminology - Are these synonyms?

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SUMMARY

The terms "probability amplitude" and "probability density" in quantum mechanics are not interchangeable. The probability amplitude is a complex number, while the probability density is a real number derived from the modulus squared of the probability amplitude. Specifically, if ##\Psi## represents a complex wave function that is a solution to Schrödinger's equation, then ##\Psi^*\Psi## yields the corresponding probability density, provided that ##\Psi## is normalized to satisfy the integral condition $$\int^{+\infty}_{-\infty}{\Psi^*\Psi dx} = 1$$.

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shanepitts
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Are the quantum mechanical terms "probability amplitude" and "probability density" used interchangeably?
 
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shanepitts said:
Are the quantum mechanical terms "probability amplitude" and "probability density" used interchangeably?

No.

The probability amplitude is complex.
The probability density is real.

Take the modulus of the probability amplitude and square it to get the probability density.
 
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craigi said:
No.

The probability amplitude is complex.
The probability density is real.

Take the modulus of the probability amplitude and square it to get the probability density.

Thanks.

So is it safe to say that a complex wave function is a probability amplitude and that its modulus squared is a probability density?
 
Safe enough for all practical purposes, provided that the complex wave function in question is a solution to Schrödinger's equation.
 
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Yes. ##\Psi## is a probability amplitude and ##\Psi^*\Psi## is the corresponding probability density, assuming that ##\Psi## has been normalized so that
$$\int^{+\infty}_{-\infty}{\Psi^*\Psi dx} = 1$$
 
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