Sub-dimensional physics

From Memory Alpha, the free Star Trek reference.

Sub-dimension physics was a field of science and physics which was studied as early as the 23rd century. The Vulcans possessed a large amount of knowledge regarding sub-dimensional physics and the field was also studied by Flint on Holberg 917G.

Flint taught Rayna Kapec all he knew about sub-dimensional physics, along with other topics such as field density and its relationship to gravity phenomena. Rayna then desired to have a conversation with Mr. Spock upon his arrival with a landing party from the USS Enterprise to Holberg in 2269. (TOS: "Requiem for Methuselah")