228 ERWIN SCHRÖDINGER
E
rwin Schrödinger was a key
figure in the advancement
of quantum physics—the
science that explains the tiniest
levels of subatomic matter. His star
contribution was a famous equation
that showed how particles moved
in waves. It formed the basis of
today’s quantum mechanics and
revolutionized the way we perceive
the world. But this revolution did
not happen suddenly. The process
of discovery was a long one, with
many pioneers along the way.
Quantum theory was originally
limited to the understanding of
light. In 1900, as part of an attempt
to solve a troubling problem in
theoretical physics known as
the “ultraviolet catastrophe,” the
German physicist Max Planck
proposed treating light as though
it came in discrete packets, or
quanta, of energy. Albert Einstein
then took the next step and argued
that light quanta were indeed a real
physical phenomenon.
Danish physicist Niels Bohr
knew that Einstein’s idea was
saying something fundamental
about the nature of light and
atoms, and in 1913 used it to solve
an old problem—the precisewavelengths of light emitted when
certain elements were heated. By
modeling the structure of the atom
with electrons orbiting in discrete
“shells” whose distance from the
nucleus determined their energy,
Bohr could explain the emission
spectra (distribution of light
wavelengths) of atoms in terms
of photons of energy given off as
electrons jumped between orbits.
However, Bohr’s model lacked a
theoretical explanation, and could
only predict the emissions from
hydrogen, the simplest atom.Wavelike atoms?
Einstein’s idea had breathed new
life into the old theory of light as
streams of particles, even though
light had also been proved, through
Thomas Young’s double-slit
experiment, to behave as a wave.
The puzzle of how light could
possibly be both particle and wave
received a new twist in 1924 from1927 saw a gathering of greats at the
Solvay Conference of physics in Brussels.
Among others are: 1. Schrödinger,
2. Pauli, 3. Heisenberg, 4. Dirac,
5. de Broglie, 6. Born, 7. Bohr, 8. Planck,
9. Curie, 10. Lorentz, 11. Einstein.IN CONTEXT
BRANCH
PhysicsBEFORE
1900 A crisis in the
understanding of light
inspires Max Planck to find
a theoretical solution that
involves treating light as
quantized packets of energy.1905 Albert Einstein
demonstrates the reality
of Planck’s quantized light
through his explanation of
the photoelectric effect.1913 Niels Bohr’s model of
the atom uses the idea that
electrons shifting between
energy levels within an atom
emit or absorb individual
quanta of light (photons).AFTER
1930s Schrödinger’s work,
along with that of Paul Dirac
and Werner Heisenberg, forms
the foundation of modern
particle physics.1
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