Atomic physics Quotes

“Fine Structure Constant: Fundamental numerical constant of atomic physics and quantum electrodynamics, defined as the square of the charge of the electron divided by the product of Planck's constant and the speed of light.”

“The significance of [the fine-structure constant] goes far beyond atomic physics, however. It is the smallness of 1/137 compared to unity that enables us to treat the coupling between the electromagnetic field and a charged particle such as an electron as a small perturbation, a fact of great computational importance. [Forces of Nature]”

“Realizing its fundamental importance in understanding spectral lines, in atomic physics and in the theory of how light and electrons interact, quantum electrodynamics, Pauli and Heisenberg were determined to derive it from quantum theory rather than introducing it from the start. They believed that if they could find a version of quantum electrodynamics capable of producing the fine structure constant, it would not contain the infinities that marred their theories.”

“The fine-structure constant is ubiquitous throughout physics. I’ve already noted its connection to the electromagnetic interaction. In atomic physics, the binding energy, fine-structure splitting, and Lamb shift are all proportional to powers of α. In condensed matter physics, α characterizes Josephson junction oscillations and quantum Hall resistance steps. In addition, α is an important component of our system of fundamental constants. [Physics Today]”

“Those who are not shocked when they first come across quantum theory cannot possibly have understood it.”