What is this called and how do I get it in latex?

[nonequilibrium]

What is this kind of diagram actually called? And how does one produce this in latex?

 

[AlephZero]

They are often called "commutative diagrams" (even when they aren't commutative!)

See http://www.jmilne.org/not/CDGuide.html for some LaTeX packages to draw them. xymatrix is about the simplest that would handle your example.