Talk:Wave packet

General lack of references; some incorrect.
Very limited references makes verifying the content of this page very difficult.

In the section Wave_packet the content around "wave-packet spreading" cites Darwin, Charles Galton. "Free motion in the wave mechanics." ''Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character'' 117.776 (1927): 258-293.

That article is available https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.1927.0179?download=true

However the article does discussed the spread of a moving Gaussian wave packet, not a stationary one. See equation 4.5. The content in the page is therefore a derived result, not encyclopedic. I believe the content is physically correct, but we have no independent way to know. Johnjbarton (talk) 18:17, 28 May 2023 (UTC)

Dubious, unreferenced claim
The current article says:

Quantum mechanics ascribes a special significance to the wave packet; In the Copenhagen interpretation, it is interpreted as a probability amplitude, its norm squared describing the probability density that a particle or particles in a particular state will be measured to have a given position or momentum.

This statement is unreferenced and incorrect. The sentence is mostly correct for a "wave function" not at all correct for a "wave packet". A wave packet is a multiple wave construct. It's interpretation is entire orthogonal to that construction. Johnjbarton (talk) 01:37, 21 June 2023 (UTC)


 * The last sentence of the same paragraph is also incorrect
 * The dispersive character of solutions of the Schrödinger equation has played an important role in rejecting Schrödinger's original interpretation, and accepting the Born rule.
 * Schrödinger's interpretation paper of May 1926 assigns the complex square of the wavefunction (again not packet) to "space-density of electricity"; Born's probability density interpretation appears in July 1926. See Whittaker V2, pg 275. Schrödinger's wave packet paper comes out in 1928 (Whittaker v2 pg 290); it's a paper about classical limits. Johnjbarton (talk) 02:18, 21 June 2023 (UTC)
 * Moreover the last and first sentence of this paragraph directly contradict each other. At first the packet is special and describes the particle; at last the dispersive character of solutions invalidate packets as descriptions. Johnjbarton (talk) 02:38, 21 June 2023 (UTC)
 * Referenced material added and off target material removed. Johnjbarton (talk) 02:51, 23 June 2023 (UTC)

"Historical background" is for wave-particle duality, not the topic wave packet.
This article incorrectly equates "wave packet" with wave particle duality. The history section is especially egregious. It does not have a single reference about the history of wave packets. Johnjbarton (talk) 02:42, 21 June 2023 (UTC)


 * Quantum wavepacket history is covered in a short chapter:
 * Kragh, H. (2009). Wave Packet. In: Greenberger, D., Hentschel, K., Weinert, F. (eds) Compendium of Quantum Physics. Springer, Berlin, Heidelberg. https://doi-org.wikipedialibrary.idm.oclc.org/10.1007/978-3-540-70626-7_232
 * It could be the basis of a rewrite of the Historical background. Classical or optical wave packets are not discussed however. Johnjbarton (talk) 04:09, 22 June 2023 (UTC)
 * I replaced the section. Johnjbarton (talk) 20:20, 22 June 2023 (UTC)

100 117.18.228.234 (talk) 16:04, 16 December 2023 (UTC)

Interesting article but
I really like the Shrödinger part where it is used as a way to show what a dispersive medium can do, but I would like to add that I don't know many particles obbeying the Shrodinger's equation. If you describe photons, you will use Maxwell's equation and quantize them as much as you can, if you look at electrons, you will deal with the Dirac equation. None of them exhibit that dispersive behavior (at least in vacuum). That dispersive behavior is a pathology of the model, it creates faster than light signals. Klinfran (talk) 10:38, 15 June 2024 (UTC)