Happy World Quantum Day.
World Quantum Day is an international celebration held annually on April 14 (4.14, a nod to Planck’s constant*, to promote public awareness and understanding of quantum science and technology.
It features global events, including lectures, lab tours, and workshops, aiming to make quantum physics more accessible.
*The value of Planck’s constant is about 4.135667696×10^−15 eV⋅Hz−1.
There is another value for it, in SI units— the one that we used in science class in high school, which came to approximately 6.62607015×10^−34 J⋅Hz−1 .
Ten to the power minus 34 is an infinitesimally small quantity and we would say about something annoying or boring ‘I care less about it than Planck’s Constant, ha ha ha 😁’ as a little inside joke, understood and appreciated by the science class nerds.
The foundational, modern quantum mechanics of the 1920s was primarily laid by Werner Heisenberg (matrix mechanics), Erwin Schrödinger (wave mechanics), Max Born (probability interpretation), and Paul Dirac (transformation theory/relativity).
They built on earlier quantum theories from Max Planck and Niels Bohr, with key contributions from Wolfgang Pauli and Louis de Broglie.
Above are diagrams of the 1s, 2s, and 3s hydrogen-atom wave functions. These are solutions to the Schrödinger equation describing an electron in the lowest orbital angular momentum state (l=0) at different energy levels.
The wave functions are spherically symmetric (no angular dependence), decay exponentially with distance from the nucleus, and possess n-1 radial nodes, representing increasing energy and distance from the nucleus.