Category: Quantum Lights and Solids

As its name suggests, about the only thing better than a semiconductor is a superconductor. You’ve probably heard this term before, and may have even learned about some of its interesting features. But just what is so super about it anyway? The name comes from the fact that these materials can carry something known as supercurrents,…

We have just mentioned that a little bit of thermal energy (heat) is enough to promote an electron from the valence band of a semiconductor into the conduction band, and therefore to initiate the flow of electricity. We also know, of course, that electrons can undergo upward quantum jumps by absorbing photons. This remains true…

Aside from the odd molecule here and there, up until now we have focused pretty much on atoms (and nuclei) in isolation. A quick glance around you, though, reveals that this is really a small part of the picture. Your house is filled with solid objects, from in your hands to the wires in your…

You’ve likely heard of the Global Positioning System—or at least its acronym, GPS—since you probably have a receiver in your car, your cellphone, or both. But did you know that GPS wouldn’t tick if not for the laws of quantum physics? This is because on board each GPS satellite is an atomic clock, the most…

The laser is one of the best examples of a quantum application because it is so widely used. We explained that excited atoms emit photons by making a quantum jump to a lower energy state. In most cases this occurs without any influence from the outside, and emissions of this variety are called spontaneous. It turns…

The forerunner for the iconic neon light was first demonstrated in 1855 by the German physicist Heinrich Geissler. He observed that a soft glow was emitted when an electric field was applied across a gas tube containing a low-pressure gas. We now understand that the applied electric field was stripping electrons from the atoms in…

Quantum physics has not only improved our fundamental understanding of nature. It has also spawned a new breed of technology, thanks in part to the ingenious experiments that validated many aspects of quantum theory over the past century. We will begin our survey of today’s quantum technologies, carefully relating each to the principles we developed…