∫d3p2π3{12Ep→e−ip⋅(x−y)|p0=Ep→+1−2Ep→e−ip⋅(x−y)|p0=−Ep→},
∫d3p2π3∫dp02πi−1p2−m2e−ip⋅(x−y).
Resp0=Ep→{−1(p0)2−(Ep→)2e−ip0⋅(x0−y0)}=12Ep→e−iEp→⋅(x0−y0),
Resp0=−Ep→{−1(p0)2−(Ep→)2e−ip0⋅(x0−y0)}=1−2Ep→eiEp→⋅(x0−y0).
(pμγμ+m)ψ(p)

“What difference does it make? As long as I’m not hurting anyone else, I should be able to live with my girlfriend.”

“I never loved my wife. Don’t I deserve to be happy?” “I needed that money more than he did, so it’s okay that I took it. Besides, he owes me for the time when…” Justification for sin comes easily to most people—including Christians. However, conscience has an ally: physics. Observation and personal experience suggest that physical laws work on the side of obedience to God’s laws.

When I began studying physics at the age of seven a particular dilemma plagued my mind. I wanted to know why the laws of physics were set up in their prescribed manner. In spite of serious study over the following twelve years, no satisfying answers came forth. Not until I became a Christian at age 19 (the…