This equation neatly sums up our current understanding of fundamental particles and forces. It represents mathematically what we call the standard model of particle physics. The top line describes the forces: electricity, magnetism and the strong and weak nuclear forces. The second line describes how these forces act on the fundamental particles of matter, namely the quarks and leptons. The third line describes how these particles obtain their masses from the Higgs boson, and the fourth line enables the Higgs boson to do the job.
The Einstein field equations in Albert Einstein's general theory of relativity describe the fundamental interaction of gravitation as a result of spacetime being curved by matter and energy.
Maxwell's equations are a set of partial differential equations that form the foundation of classical electrodynamics, classical optics, and electric circuits.
General form of Schrodinger's equation, the basis of quantum mechanics. The Schrödinger equation describes how the quantum state of a physical system changes with time.