Is Nature's Preferred Wave Packet Shape Gaussian?

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SUMMARY

The discussion confirms that Gaussian functions are frequently utilized as amplitude functions for single-particle wave packets due to their mathematical convenience, particularly because the Fourier Transform of a Gaussian is also a Gaussian. Empirical evidence suggests that inhomogeneities, such as those caused by Doppler broadening, lead to Gaussian shapes in natural linewidths. The relationship between statistical rules and wave packet shapes indicates that while Gaussian wave packets can be created experimentally, they also simplify theoretical models by minimizing the uncertainty principle, expressed as Δx Δp = ħ.

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  • Understanding of Gaussian functions and their properties
  • Familiarity with Fourier Transforms
  • Knowledge of quantum mechanics, specifically wave packets
  • Basic concepts of statistical mechanics, including Poisson and normal distributions
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LarryS
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A Gaussian function is often chosen as the amplitude function for the wave packet of a single particle. It is handy because the Fourier Transform of a Gaussian is also a Gaussian. So the position and momentum representations would both be Gaussians.

But is there any empirical evidence that nature prefers Gaussians for single-particle wave packets?

Thanks in advance.
 
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The shape of things are usually related to the statistical rules under which they form.

For example, for linewidths, the shape of the natural linewidth is obtained from the underlying rule that an atom has a uniform probability per unit time to decay, i.e. it follow poisson statistics. From this the Lorentizan lineshape follows automatically.
When a line instead is not limited by decay, but for example, as is very common, by doppler broadening, then the shape changes. Doppler broadening is an inhomogeneous effect, i.e. each photon may be narrow, as all are different they sum up to a broader shape following the normal distribution, and from this it follows that the line now has a Gaussian shape.

Infact, as far as I know, inhomogeneities usually gives rise to gaussians.

This may not be exactly what you asked, but I think that if it's a wavepacket that you create somehow, then you have the freedom to also select it's shape, and experimentally it is possible to create gaussian wavepackets, so there's certainly no problem with using them in the theory if it makes it simpler.
 
Gaussians minimize the uncertainty relationship. I.e. \Delta x \Delta p = \hbar for gaussians.
 

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