lepton_veecee Posted November 13, 2014 Posted November 13, 2014 Is there a upper limit for EM wave frequency and minimum wavelength
Enthalpy Posted November 13, 2014 Posted November 13, 2014 If there's a physical limit, it exceeds by far the technology's capability. We can produce photons in colliders, supposedly of a few TeV. Cosmic rays contain much bigger energies; whether each one has been a photon or something else is hard to determine, but they do result partially in photons in a shower. One limit on the propagation over big distances could be the interaction with other photons making the cosmic background. It's not a limit on the existence of photons. An other limit would be a minimum length predicted by unification theories. Very far both from technology limits and from observed photon energies.
elfmotat Posted November 13, 2014 Posted November 13, 2014 (edited) The only cutoff I can think of would be at the Planck energy scale, where it would likely turn into a black hole. Edited November 13, 2014 by elfmotat
Sensei Posted November 14, 2014 Posted November 14, 2014 The only cutoff I can think of would be at the Planck energy scale, where it would likely turn into a black hole. Black hole from photon... ? Please elaborate this speculation..
elfmotat Posted November 14, 2014 Posted November 14, 2014 Black hole from photon... ? Please elaborate this speculation.. http://en.wikipedia.org/wiki/Planck_scale#Theoretical_ideas
Sensei Posted November 14, 2014 Posted November 14, 2014 AFAIK black hole must exist in the all reference frames to be black hole. Photon doesn't have reference frame.
elfmotat Posted November 14, 2014 Posted November 14, 2014 AFAIK black hole must exist in the all reference frames to be black hole. Photon doesn't have reference frame. I'm not sure I understand. What do photons having rest frames have to do with them turning into a black hole?
Sensei Posted November 14, 2014 Posted November 14, 2014 (edited) I'm not sure I understand. What do photons having rest frames have to do with them turning into a black hole? In one frame of reference f.e. v=0, [math]\gamma = 0[/math], photon has one frequency/wavelength/energy when we will be detecting the same photon from other frame of reference f.e. v=0.5, [math]\gamma=1.1547[/math], photon might be redshifted, or blueshifted, and appearing having lower or higher energy.. Edited November 14, 2014 by Sensei
elfmotat Posted November 15, 2014 Posted November 15, 2014 In one frame of reference f.e. v=0, [math]\gamma = 0[/math], photon has one frequency/wavelength/energy when we will be detecting the same photon from other frame of reference f.e. v=0.5, [math]\gamma=1.1547[/math], photon might be redshifted, or blueshifted, and appearing having lower or higher energy.. The event would have to take place at some sort of interaction vertex. A high energy photon could scatter off something (an electron, another photon, etc.) with one of the products being a black hole. A free photon won't spontaneously collapse, for the reason you mention.
Sensei Posted November 15, 2014 Posted November 15, 2014 (edited) The event would have to take place at some sort of interaction vertex. A high energy photon could scatter off something (an electron, another photon, etc.) with one of the products being a black hole. A free photon won't spontaneously collapse, for the reason you mention. After pair production, it won't be photon anymore, but particle at its antiparticle (or shower of them). But they have concentrated mass, and high kinetic energy. The highest energy photons ever detected: http://en.wikipedia.org/wiki/Ultra-high-energy_gamma_ray The highest kinetic energy believed to be proton ever detected: http://en.wikipedia.org/wiki/Oh-My-God_particle http://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray Edited November 15, 2014 by Sensei
elfmotat Posted November 15, 2014 Posted November 15, 2014 After pair production, it won't be photon anymore, but particle at its antiparticle (or shower of them). But they have concentrated mass, and high kinetic energy. The highest energy photons ever detected: http://en.wikipedia.org/wiki/Ultra-high-energy_gamma_ray The highest kinetic energy believed to be proton ever detected: http://en.wikipedia.org/wiki/Oh-My-God_particle http://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray Sorry, but I don't see what any of that has to do with anything.
ajb Posted November 15, 2014 Posted November 15, 2014 In standard quantum electrodynamics there is no cut-off for the energy of a photon. However, we cannot expect that QED will be a good theory for all energies, and as elfmotat has hinted at the quantum nature of space-time itself will become important somewhere near the Planck scale. Maybe before that we will have to take into account new physics.
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