The Drude model

[janneman]

A plasmon is a quantum of a plasma oscillation. The plasmon is the quasiparticle resulting from the quantization of plasma oscillations just as photons and phonons are quantizations of light and sound waves, respectively. Thus, plasmons are collective oscillations of the free electron gas density, often at optical frequencies.

Jan Didden

[john curl]

It exists, but it is not important?

[lineup]

Originally posted by john curl
It exists, but it is not important?

I exists, but I is not important
.. not to You

[janneman]

Originally posted by john curl
It exists, but it is not important?

The Drude model is the application of kinetic theory to electrons in a solid. It assumes that the material contains immobile positive ions and an "electron gas" of classical, non-interacting electrons of density n, each of whose motion is damped by a frictional force due to collisions of the electrons with the ions, characterized by a relaxation time ô. This simple classical model provides a very good explanation of DC and AC conductivity in metals, the Hall effect, and thermal conductivity (due to electrons) in metals. The model explains the Wiedemann-Franz law.

Jan Didden

[john curl]

Approximations are not completely accurate. That is why we study the QM model, and why exceptions can prove the rule. It is also why many here cannot believe in newer technology, because they rely on the Drude model that is obsolete for real physicists, but a close approximation for engineers. Kind of like the planetary model of the atom with the electrons whizzing around the nucleus. Works pretty good for high school chemistry, don't you agree?

[john curl]

As I suspected.

[Steve Eddy]

Originally posted by john curl
Approximations are not completely accurate. That is why we study the QM model, and why exceptions can prove the rule. It is also why many here cannot believe in newer technology, because they rely on the Drude model that is obsolete for real physicists, but a close approximation for engineers. Kind of like the planetary model of the atom with the electrons whizzing around the nucleus. Works pretty good for high school chemistry, don't you agree?

Yes, John, you've said this numerous times in the past.

Problem is, that's all you ever say. You've never offered up anything, Drude, QM or otherwise, to explain any of this "newer technology" that you speak of.

It's just more bluff, bluster and buzzwords intended to impress those who don't know any better.

se

[janneman]

OTOH, if you think about phenomena like synaesthesia, a neurologically-based phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway, it becomes much clearer.

In one common form of synaesthesia, known as grapheme or color synaesthesia, letters or numbers are perceived as inherently colored, while in ordinal linguistic personification, numbers, days of the week and months of the year evoke colors or personalities.
In spatial-sequence, or number form synaesthesia, numbers, months of the year, and/or days of the week elicit precise locations in space (for example, 1980 may be "farther away" than 1990), or may have a (three-dimensional) view of a year as a map (clockwise or counterclockwise).

While cross-sensory metaphors (e.g., "loud shirt", "bitter wind" or "prickly laugh") are sometimes described as "synaesthetic", true neurological synaesthesia is involuntary. It is one reason why we are more sensitive to low-frequency sound when it is associated with a larger, dark object, and why a bright, small object illicits associations with higher frequency sounds.
Synaesthesia provides a scientific footing for the need for DBT in audio.

Jan Didden

[h_a]

Approximations are not completely accurate. That is why we study the QM model, and why exceptions can prove the rule.

The Drude-model is a meanfield theory and meanfield theories (like density functional theory) were and still are rather essential in solid state physics. Even convential superconductivity is explained by the BCS-theory which is essentially a meanfield-theory.

Coming back to the Drude-model: every model is valid within its limitations; so for the usual metalls, it is perfectly applicable for DC and AC. There are no exceptions, only cases where the conditions for validity are not met.

I'm wondering what you mean by QM; probably quantum mechanics. Quantum mechanics are not focused especially on electron interactions as such, it's just the application of the Schrödinger equation which incorporates a general interaction term (whatever it might be).

Since this problem (electronic interaction in a solid) is unsolvable as such, there will always be approximations.

And what is constantly forgotten here, is the classical limit which demands that all quantum fun has to converge to classical behaviour for large dimensions. Large being at least on the magnitude of micrometers and up. That is already a very generous number.

Quantum mechanics became here a new buzzword that is taken to explain otherwise not explainable audio phenomena, however I don't see anything that would give reason for its applicability.

Have fun, Hannes

[john curl]

Engineers use the Drude model, physicists use the QM model. Look it up. If some of you would read serious books on this stuff, you would easily understand that there is a difference. Most here do not have the prerequisites for understanding it however. I certainly have a difficult time and can't break it down to bite sized pieces for technicians or even most practicing engineers to understand. You have to try, on a personal basis, to understand that there is a difference, and that it might be useful and important, sometimes, like a 'tunnel diode' can be useful, yet impossible to explain with the Drude model or the like.