• Quantum field theory, developed from the late 1920s through the 1940s and beyond, posited that not only particles, but the quantum fields underlying them were fundamental.
• For decades, scientists argued over whether quantum fields were truly real, or whether they were simply calculational tools, useful for describing the behavior of observable particles.
• In recent years, however, a number of separate experiments appear to have settled the issue: quantum fields carry energy, and that can be observed. If energy is real, and it is, then so are quantum fields.
One of the biggest questions that appears right at the intersection of physics and philosophy is as simple as it is puzzling: what is real? Is reality simply described by the particles that exist, atop a background of spacetime described by General Relativity? Is it fundamentally wrong to describe these entities as particles, and must we consider them as some sort of hybrid wave/particle/probability function: a more complete description of each “quantum” in our reality? Or are there fields, fundamentally, that underpin all of existence, where the “quanta” that we typically interact with are simply examples of excitations of those fields?
When quantum mechanics arrived on the scene, it brought with it the realization that quantities that were previously thought to be well-defined, like:
• the position and momentum of a particle,
• its energy and location in time,
• and its angular momentum in each of the three spatial dimensions that we have,
could no longer be assigned values, only a probability distribution for what values they could take on. Although this weirdness, on its own, brought about many arguments over the nature of reality, things would soon get even weirder with the introduction of quantum fields. For generations, physicists argued whether those quantum fields were actually real, or whether they were simply calculational tools.
Nearly a full century later, we’re certain that they’re real for one unambiguous reason: they carry energy. Here’s how we found out.
Quantum theory came about because >>> Read More
