- #1
kderakhshani
- 13
- 0
Hi everybody,
In most classical or quantum optics texts an angular momentum is considered for the EM radiation as the following:
[itex] J = ε_0 ∫_V r × [E(r, t) × B(r, t)] d^3 r [/itex]
Then it is claimed that:
"Using the usual formula for a double vector product and integrating by parts, bearing in
mind the assumption that the fields are zero at the surface of volume V introduced for the
mode expansion, one finds that JR can be written as a sum of two terms:
[itex]J = L + S , [/itex]
given by
[itex]L = ε_0 ∑_{j=(x,y,z)} ∫d^3r Ej (r, t)(r × ∇)Aj (r, t) ,[/itex]
[itex]S = ε_0 ∫d^3r E(r, t) × A(r, t) [/itex]
"
Would you please help me derive them?
Thank you
In most classical or quantum optics texts an angular momentum is considered for the EM radiation as the following:
[itex] J = ε_0 ∫_V r × [E(r, t) × B(r, t)] d^3 r [/itex]
Then it is claimed that:
"Using the usual formula for a double vector product and integrating by parts, bearing in
mind the assumption that the fields are zero at the surface of volume V introduced for the
mode expansion, one finds that JR can be written as a sum of two terms:
[itex]J = L + S , [/itex]
given by
[itex]L = ε_0 ∑_{j=(x,y,z)} ∫d^3r Ej (r, t)(r × ∇)Aj (r, t) ,[/itex]
[itex]S = ε_0 ∫d^3r E(r, t) × A(r, t) [/itex]
"
Would you please help me derive them?
Thank you