Albert Einstein and Erwin Schrödinger may not have always gotten along, but they were both leading thinkers in the field of quantum mechanics. They did agree on one thing: Quantum jumps, where an electron within an atom instantaneously changes from one discrete energy level to another discrete energy level, were just too weird to deal with. And nearly a century later, most physicists would not challenge the fact that this is an accepted part of how we understand the field.
But most is not all, and challenging widely-accepted principles is the foundation of science. In early June, a team of physicists from Yale published new results showing that quantum jumps are more predictable than previously thought, and that the electron's jump between energy states can even be reversed mid-jump.
This group of researchers built an artificial atom that would perform jumps between a low energy, ‘ground’ state, a ‘bright’ (higher energy) state and a ‘dark’ state. They fired a beam of microwave photons into the artificial atom and observed that photon absorption caused it to switch from ground to bright states. And when a particularly high energy photon was absorbed, the atom would jump all the way up to the dark state and stay there for an extended period of time.
The tricky part of the setup is that it is impossible for scientists to directly observe an atom transitioning between states. So instead, the Yale researchers measured the photon emission from the bright state (identified by the specific way light scattered from this energy level), which was recorded as a clicking sound. An interesting pattern rapidly emerged: The clicks that were given off by photon emission suddenly decreased in frequency each time right before the atom jumped to the low-energy state. From there, they found that it was possible to observe the jump simply by cutting off the photon beam into the atom chamber and that the jump process could actually be reversed by hitting the atom with an electrical pulse.
This is a big breakthrough for quantum mechanics, because it means that we’ve now developed a technique to predict and control quantum systems that previously seemed highly random, uncontrollable, and just plain weird. This technique puts rapid increases in quantum computing technology within our reach.
Talk about exciting new physics! I wonder what Einstein and Schrödinger would think.