The thought experiment known as Schrödinger’s cat is one of the most famous and misunderstood concepts in quantum mechanics. By thinking deeply about it, researchers have come to some impressive discoveries about physical reality.
According to an article in Quanta Magazine, Austrian physicist Erwin Schrödinger, who helped found quantum mechanics, first conceived of his cat puzzle in 1935 as a commentary on problems originally posed by luminary Albert Einstein.
As they developed their new understanding of the subatomic realm, most of Einstein and Schrödinger’s colleagues realized that quantum entities exhibited extremely strange behavior. The Danish physicist Niels Bohr championed the idea that particles like electrons had no well-defined properties until they were measured. Before that, particles existed in what was called a superposition of states, with, for example, a 50% chance of being oriented “up” and a 50% chance of being oriented “down.”
Einstein, in particular, did not like this half-hearted explanation. He wanted to know how exactly the universe knew that someone was measuring something. Schrödinger highlighted this absurdity with his notorious conceptual cat.
Suppose someone builds a strange contraption, Schrödinger wrote in a 1935 paper called “The Current Situation in Quantum Mechanics.” The apparatus consists of a box containing a sealed vial of cyanide, above which hangs a hammer attached to a Geiger counter, aimed at a small piece of weakly radioactive uranium. Inside the box is also a kitten (and remember, this is a thought experiment that has never been performed).
The box is sealed and the experiment is left to run for a certain amount of time, perhaps an hour. During that hour, the uranium, whose particles obey the laws of quantum mechanics, has a chance of emitting radiation that will then be detected by the Geiger counter, which in turn will release the hammer and smash the test tube, killing the cat by cyanide poisoning.
Schrodinger’s cat. fandom.com
According to people like Bohr, until the box is opened and the cat’s status is “measured,” it will remain in a superposition of both alive and dead. People like Einstein and Schrödinger rejected this possibility, which is inconsistent with everything our ordinary experience tells us—that cats are either alive or dead, but not both.
“Quantum physics was missing a crucial ingredient: a story about how it relates to things in the world,” wrote science journalist Adam Becker in his book What’s Real? (Basic Books, 2018). “How do the phenomenal numbers of atoms governed by quantum physics give rise to the world we see around us?”
Schrödinger’s cat got to the heart of what’s odd about Bohr’s interpretation of reality: the lack of a clear boundary between the quantum and everyday realms. While most people think of this as an example of particles that don’t have well-defined properties until they’re measured, Schrödinger’s original intention was the opposite: to show that such an idea is meaningless. Yet for decades, physicists largely ignored the problem, moving on to other dilemmas.
See also... New method for observing individual atoms confirms century-old quantum mechanical theory |
But since the 1970s, researchers have been able to show that quantum particles can be created in states that always match each other — so that if one shows an “up” orientation, the other will be “down” — a phenomenon that Schrödinger called entanglement. Such work has been used to support the new field of quantum computing, which promises to produce machines that are much faster than today’s technology.
In 2010, physicists also managed to create a real-life version of Schrödinger’s cat, albeit in a way that didn’t involve felicidide (aka kitten murder). Scientists at the University of California, Santa Barbara, built a resonator, essentially a tiny tuning fork about the size of a pixel on a computer screen. They put it into a superposition in which it both oscillated and didn’t oscillate at the same time, showing that relatively large objects can occupy strange quantum states.
Superposition is a composition of functions (a complex function). The principle of superposition is a principle in physics and mathematics that describes the superposition of processes (for example, waves) and, as a consequence, the occurrence of constructive and destructive interference. The principle of superposition is an assumption according to which the resulting effect of several independent actions is the sum of the effects caused by each action separately. It is valid for systems or fields that are described by linear equations. Usually, superposition is understood as a simple observation: if one action leads to one result, and a second action to a second, then their combined action will produce both results.
More recent experiments have placed groups of up to 2,000 atoms in two different places at once, further blurring the line between the microscopic and the macroscopic. In 2019, researchers at the University of Glasgow even managed to take a photograph of entangled photons using a special camera that snapped a picture every time a photon appeared with its entangled partner.
Although physicists and philosophers have not yet reached a consensus on how to understand the quantum world, Schrödinger’s ideas have opened up many fruitful avenues of research and will likely continue to do so for the foreseeable future.
See also... Complete list of HTML/Javascript event handlers with examples List of required documents for a website in the Russian Federation |
Related Posts
Self-aware universe. How consciousness creates the material world. Chapter 6. The Nine Lives of Schrödinger’s Cat
CHAPTER 6. NINE LIVES OF SCHRÖDINGER’S CAT Many of the…
Definitions, axioms and key concepts of quantum physics
Quantum mechanics, or quantum physics, is a set of scientific…
