Subspace field mechanics was a sub-discipline within the mechanics field of physics.
Doctor Telek R'Mor was surprised by B'Elanna Torres' feat of binding a transporter beam into visual link between the Talvath and the USS Voyager through a micro-wormhole, when she matched his data transmission to the phase amplitude of the com signal. While the technology existed in the 2370s, it did not exist in the 2350s, the time period that R'Mor lived in. His learning of this technology was described by R'Mor as "an incredible breakthrough in subspace field mechanics." (VOY: "Eye of the Needle")
In an alternate timeline, Jake Sisko started studying subspace mechanics at the age of 37. He tried to find a way to help his father out of his temporal displacement. (DS9: "The Visitor")