Can QFT adequately describe the elusive properties of photons?

Gal
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What is the photon's equivalence of the electron's wavefunction? Can I measure qualities of the photon that will collapse into an eigenstate? What properties of the photon aren't fixed?
 
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Gal said:
What is the photon's equivalence of the electron's wavefunction? Can I measure qualities of the photon that will collapse into an eigenstate? What properties of the photon aren't fixed?
The photon is inherently relativistic and only properly described by quantum field theory. With that said, the QM analogy to the single photon's wave function is the complex electromagnetic field, E + iB. Google "photon wave function" and you will get quite a few references. And to draw the QM analogies further, neither position, momentum, or polarization are necessarily fixed.
 
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Heinera said:
The photon is inherently relativistic and only properly described by quantum field theory. With that said, the QM analogy to the single photon's wave function is the complex electromagnetic field, E + iB. Google "photon wave function" and you will get quite a few references. And to draw the QM analogies further, neither position, momentum, or polarization are necessarily fixed.

The photon follows Maxwell's equation to form a wave according to the wave formula with velocity c. But this is fundamentally different from an electron's wave function that obeys the Schrodinger equation (first partial derivative in time opposed to second...) and that describes the probalistic state of the electron.
Where exactly is the uncertainty described in photons? How do I "measure" something and what "collapses" with respect to what "operator"?
 
Gal said:
The photon follows Maxwell's equation to form a wave according to the wave formula with velocity c. But this is fundamentally different from an electron's wave function that obeys the Schrodinger equation (first partial derivative in time opposed to second...) and that describes the probalistic state of the electron.
Essentially yes, so you should now go on to study quantum field theory, which is the proper theory for photons.
 
Gal said:
The photon follows Maxwell's equation to form a wave according to the wave formula with velocity c.
I would say not. The photon is not an electromagnetic wave, even if it has some properties of the em wave.

--
lightarrow
 
Gal said:
Where exactly is the uncertainty described in photons? How do I "measure" something and what "collapses" with respect to what "operator"?

Photons can't be described by ordinary QM because position is not an observable for photons (that position is an observable is a basic assumption of QM). It can only be described by QFT where the concepts you are alluding to above are much more nebulous eg in QFT even particle number isn't certain. Before moving onto QFT it would be wise to be reasonably conversant with ordinary QM. However once you are some good books are starting to appear that will allow you to learn QFT eg
https://www.amazon.com/dp/019969933X/?tag=pfamazon01-20

Thanks
Bill
 
Not an expert in QM. AFAIK, Schrödinger's equation is quite different from the classical wave equation. The former is an equation for the dynamics of the state of a (quantum?) system, the latter is an equation for the dynamics of a (classical) degree of freedom. As a matter of fact, Schrödinger's equation is first order in time derivatives, while the classical wave equation is second order. But, AFAIK, Schrödinger's equation is a wave equation; only its interpretation makes it non-classical...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
Is it possible, and fruitful, to use certain conceptual and technical tools from effective field theory (coarse-graining/integrating-out, power-counting, matching, RG) to think about the relationship between the fundamental (quantum) and the emergent (classical), both to account for the quasi-autonomy of the classical level and to quantify residual quantum corrections? By “emergent,” I mean the following: after integrating out fast/irrelevant quantum degrees of freedom (high-energy modes...

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