TheCanadian said:When converting from one form of energy to another, what force-carrying particles are involved in converting acceleration (or more generally a change in kinetic energy) of charged particles into electromagnetic radiation as observed in bremsstrahlung emission?
PeterDonis said:None. Charged particles interact directly with photons (EM radiation).
That interaction would violate several conservation laws, including charge and lepton number.TheCanadian said:Why is this not ordinarily observed for any two massive particles (e.g. an electron and another electron)?
Nugatory said:That interaction would violate several conservation laws, including charge and lepton number.
A particle/antiparticle interaction is pretty much the only annihilation that is guaranteed not to violate any conservation laws.
TheCanadian said:If one could hypothetically construct a particle that has all of the same properties as a positron (e.g. charge, lepton number) except for mass, would it still be able to annihilate with an electron?
PeterDonis said:This is not a hypothetical; it's actually realizable, and the answer is no. There are three "families" of leptons in the Standard Model: the electron family, the muon family, and the tau family. (Each family contains a charged lepton and its antiparticle, and an uncharged lepton and its antiparticle; in the electron family these are the electron/positron and the electron neutrino/antineutrino.) Each lepton can only annihilate with its own antiparticle, the one in the same family and with opposite charge. The neutrinos (electron, muon, and tau, each with its own antiparticle) are particularly interesting in this regard, since they have no conserved charges other than lepton number.
The underlying reason for all this is that, in quantum field theory, particles and antiparticles are not just two separate things that happen to be opposites in all conserved charges. They are states of the same underlying quantum field. (The technical term is that they are CPT conjugates of each other.) The process we have been describing as "annihilation", from the viewpoint of QFT, is just a difference in the state of the quantum field between one region of spacetime and another.
TheCanadian said:Well that's fascinating. It seems like fairly standard QFT, but do you have any particular resources/texts you would suggest for this topic (and perhaps QFT more generally)?
bhobba said:First what's your level of stnadard QM?
Thanks
Bill
"Change in the form of energy" refers to the transformation of energy from one form to another. This can occur through processes such as chemical reactions, mechanical work, or heat transfer.
Energy changes form in order to maintain a balance in the universe. The law of conservation of energy states that energy cannot be created or destroyed, but it can be converted from one form to another.
Energy can be converted from one form to another through various processes, such as heat transfer, electrical work, or nuclear reactions. For example, when a light bulb is turned on, electrical energy is converted into light and heat energy.
There are many different forms of energy, including kinetic energy (energy of motion), potential energy (stored energy), thermal energy (heat), chemical energy (stored in bonds between atoms), and electromagnetic energy (light and radiation).
"Change in the form of energy" impacts our daily lives in numerous ways. For example, we use electrical energy to power our homes and devices, chemical energy in the food we eat for fuel, and thermal energy to keep us warm. Understanding energy and its transformations is crucial for our daily activities and the functioning of our society.