Okej, jag har läst igenom artiklarna, och den artikeln som gav mest vad wikipedias engelska artikel. Skriver resten på engelska för att bespara er lustiga översättningar.
What I don't understand from the discription given by wikipedia is when it says, syllogistically:
- In a material, photons couple to the excitations of the medium.
- "Coupling" means here that photons can transform into these excitations (that is, the photon gets absorbed and medium excited, involving the creation of a quasi-particle) and vice versa (the quasi-particle transforms back into a photon, or the medium relaxes by re-emitting the energy as a photon). However, as these transformations are only possibilities, they are not bound to happen and what actually propagates through the medium is a polariton; That is the quantum-mechanical superposition of the energy-quantum, i.e. the q-m superposition of the photon; being a photon and of it being a quasi-particle matter excitations. That is; the linear combination of the two eingenstate of the photon and the electron.
- Thus, a polariton is the result of the mixing of a photon with an excitation of a material. The most discussed types of polaritons are [...]; exciton-polaritons, resulting from coupling of visible light with an exciton;
- The linear combination of two or more eigenstates results in quantum superposition of two or more values of the quantity.
- An exciton is a bound state of an electron [its eingenstate???] and an imaginary particle called an electron hole in an insulator or semiconductor, and such is a Coulomb correlated electron-hole pair. It is an elementary excitation, or a quasiparticle of a solid.
So what does it say? There IS a photon coupling (1), which is photons transforming into polaritons (3) by the superpositioning (4) of the electron- (5) and quantum/photon-eigenstates (2), into the quasi-particle: "exciton-polaritons" (3).
What bothers me is that it also states that the photon absorptions/transformations doesn't necessaryly happen (2). The quasi-particle is the polariton (probably named from the electron-polarity from its spin?)
Have I understood it correctly?
Glitter skrev:
Kan man inte gärmföra det med en tratt?
Altså är det mer "grejer" ivägen ju mer densitet det är och därför tar det längre tid att komma ignom presis som man hade hält vatten i en tratt med litet hål gämfört med ett stort hål...
/R Orkade inte läsa i länkarna kanske är förklarat där...
Kanske lite väl simplifierat.
Svensk forskarsnubbe skrev:
I material finns det massvis med elektriskt laddade partiklar: protoner och elektroner. De påverkas av det elektromagnetiska fältet, och de påverkar också fältet.
Så ju högre optisk densitet, desto mer ...?
Då är frågan - vad är det som gör att den går långsammare på grund av superpositioneringen?
Wp/ skrev:
Matter excitations have a non-linear dispersion relation; that is, their momentum is not proportional to their energy. Hence, these particles propagate slower than the vacuum speed of light. (The propagation speed is the derivative of the dispersion relation with respect to momentum.) This is the formal reason why light is slower in media (such as glass) than in vacuum. (The reason for diffraction can be deduced from this by Huygens' principle.) Another way of phrasing it is to say that the photon, by being blended with the matter excitation to form a polariton, acquires an effective mass, which means that it cannot travel at c, the speed of light in a vacuum.****
Can you say that the photon enters the medium, interferes with the electron(s) to create a matter excitation/an exciton, whereafter the same photon's eigenstate becomes quantum mechanically superpositioned with the eigenstate of the quasi-particle-exciton, forming the exciton-polariton, which cannot go above c, because it has rest-mass?
Svaret till varför den får restmassa kanske har något att göra med
The propagation speed is the derivative of the dispersion relation with respect to momentum.
? Har den rest-massa över huvud taget, eller är det bara ett sätt att uttrycka det?
