The discussion centers on the interpretation of the speed of light (c) in Quantum Electrodynamics (QED) and its implications for Special Relativity. Duff argues that c is merely a transformation factor rather than a fundamental constant, suggesting that setting c=1 alters the understanding of QED at small distances. Participants explore the notion that c serves as a conversion factor between space and time, emphasizing the identity ds²=dx²+dy²+dz²-(cdt)². This perspective leads to the conclusion that time can be treated as a fourth dimension, reinforcing the idea that the choice of units influences the interpretation of physical phenomena.
PREREQUISITESPhysicists, students of theoretical physics, and anyone interested in the foundational concepts of Quantum Electrodynamics and Special Relativity.
This issue actually has nothing to do with quantum effects; it's just the way Special Relativity is interpreted. Some people like to think of the speed of light as a conversion factor between space and time. For instance, they would say that there is no difference between 1 year and 1 light-year. They do this because of the identity ds^2=dx^2+dy^2+dz^2-(cdt)^2. Note that the last quantity that gets squared is not dt, but cdt. So you can think of time as a fourth dimension w=ct. The authors who think along these lines often make the claim that everything in the universe is moving in the time direction with a constant speed c (although that's strange, because speed is distance over time).exponent137 said:In QED calculations are made with variable c.
But Duff says that c does not exists, because it is only a transformation factor. So if we put c=1 how QED is changed at small distances?