In this article we provide a manifestly gauge-invariant approach to charged particles. It involves (1) Green functions of gauge-invariant operators and (2) Feynman rules which do not depend on any kind of gauge-fixing condition. First, we provide a thorough analysis of QED. We propose a specific set of gauge-invariant Green functions and describe a manifestly gauge-invariant technique to evalua...

In this article we provide a manifestly gauge-invariant approach to charged particles. It involves (1) Green functions of gauge-invariant operators and (2) Feynman rules which do not depend on any kind of gauge-xing condition. First, we provide a thorough analysis of QED. We propose a speciic set of gauge-invariant Green functions and describe a manifestly gauge-invariant technique to evaluate ...