“
e=mc^2. I know. I promised there would be no equations and, except for a few footnotes, I've kept my promise. But I think you will forgive me for making an exception for the world's most famous equation-the only equation to have its biography written. And the thing is this: e = mc^2 pops right out of QFT. Einstein had to work hard to find it (it was published in a separate paper that followed his breakthrough paper on relativity theory in 1905), but in QFT it appears as an almost trivial consequence of the two previous results. Since both mass and energy are associated with oscillations in the field, it doesn't take an Einstein to see that there must be a relationship between the two. Any schoolboy can combine the two equations and find (big drum roll, please) e = mc^2. Not only does the equation tumble right out of QFT, its meaning is seen in the oscillations or "shimmer" of the fields. Frank Wilczek calls these oscillations "a marvelous bit of poetry" that create a "Music of the Grid" (Wilczek's term for space seen as a lattice of points):
Rather than plucking a string, blowing through a reed, banging on a drumhead, or clanging a gong, we play the instrument that is empty space by plunking down different combinations of quarks, gluons, electrons, photons,...and let them settle until they reach equilibrium with the spontaneous activity of Grid...These vibrations represent particles of different mass m...The masses of particles sound the Music of the Grid. ----- Frank Wilczek
”
”
Rodney A. Brooks (Fields of Color: The theory that escaped Einstein)