In a physical theory, a field equation describes how the fundamental forces interact with matter. The four fundamental forces are gravitation, electromagnetism, strong interaction and weak interaction.
Before the theory of quantum mechanics was fully developed, there were two known field theories, namely gravitation and electromagnetism (these two are sometimes referred to as classical field theories, as they were formulated before the advent of quantum mechanics, and hence do not take into account quantum phenomena).
Modern field equations tend to be tensor equations.
Read more about Field Equation: Relativistic Fields, Unification Attempts
Famous quotes containing the words field and/or equation:
“An enormously vast field lies between “God exists” and “there is no God.” The truly wise man traverses it with great difficulty. A Russian knows one or the other of these two extremes, but is not interested in the middle ground. He usually knows nothing, or very little.”
—Anton Pavlovich Chekhov (1860–1904)
“Jail sentences have many functions, but one is surely to send a message about what our society abhors and what it values. This week, the equation was twofold: female infidelity twice as bad as male abuse, the life of a woman half as valuable as that of a man. The killing of the woman taken in adultery has a long history and survives today in many cultures. One of those is our own.”
—Anna Quindlen (b. 1952)