WebIt must necessarily be so, as off-shell matrix elements don't make formal sense: Matrix elements are taken between states, and all physical states are on-shell by the basic structure of QFT. Thus thestructure of QFT itself enforces a fundamental distinction between real particles representable by states and virtual particles representable by propagators … Web11 de jul. de 2024 · $\begingroup$ half off-shell could correspond to partially on-shell currents, for example a three-point vertex with two legs on-shell. $\endgroup$ – Akoben Jul 15, 2024 at 18:14
Where does this term "shell" with prefix "on-/off-" come from?
Web24 de out. de 2024 · Shell is an interface between a user and OS to access to an operating system's services. It can be either GUI or CLI (Command Line interface). sh (Bourne … Web36. It's important to distinguish them because on-shell and off-shell are opposite to each other, in a sense. On-shell describes fields that obey the equations of motion and real … cthulhu great grandfather
Difference between Login Shell and Non-Login Shell?
Web15 de mai. de 2024 · This fact can be used to explain why either equation of motion by itself, the one for ψ or the one for A, implies the conservation law ∂ μ j μ = 0. I assume that's what Srednicki meant by the statement that the paradox is solved by appealing to gauge symmetry. (1) δ S A δ θ = 0 δ S ψ δ θ = 0. (2) ∂ μ δ S A δ A μ = 0. Web409. = and == are for string comparisons. -eq is for numeric comparisons. -eq is in the same family as -lt, -le, -gt, -ge, and -ne. == is specific to bash (not present in sh (Bourne shell), ...). Using POSIX = is preferred for compatibility. In bash the two are equivalent, and in sh = is the only one that will work. Web25 de mai. de 2009 · Off shell means not real (not physical), and is only used in the maths. Off shell occurs only in the middle of calculations, never at the beginning or end. Energy and momentum conservation applies to both on shell and off shell equations (but E 2 = p 2 + m 2 , which applies to each particle individually, does not apply off shell). earth line choke