That furry feline friend of Schroedinger’s has become a staple for quantum physics fans everywhere. The cat’s ambiguous fate relates to scientists’ interpretation of quantum mechanics that deals only in probabilities.
In quantum mechanics, when physicists make an exact measurement, they find only one possible solution from many. Instead, most often they quantify the probability of an object’s position, momentum and other physical quantities falling within a certain range of possible values.
In the simple case of Schrodinger’s cat, when you observe the cat’s state, it will be either alive or dead. And that outcome will randomly change each time you run the experiment. Mathematically, how does Schroedinger’s cat fit into the equivocal universe of quantum mechanics?
|James Binney, Quantum Mechanics Discussions at Oxford University. Credit: Oxford University|
A good start to grasping this is to first understand Schroedinger’s equation. It’s an intimidating jumble of symbols to the untrained eye, but to theoretical physicists and Oxford professor James Binney it is a “central, crucial, vital equation” in quantum mechanics - a field of science that explains the structure and behavior of anything and everything around us, he explains in the first lecture of his online series "Quantum Mechanics."
By listening to his first four publicly available and free lectures, you can witness the birth of a collage of quantum notations as Binney beautifully unfolds the Schroedinger equation and it’s components in his Oxford classroom, which is complete with 20 sliding chalkboards that he fills as the 45-minute lecture progresses.
Binney’s class is one of many free and available lecture series on quantum mechanics that are part of the Massive Open Online Course, taught for varying levels of expertise, which you can access at your leisure.
If quantum physics is not your cup of tea, then there are dozens of other physics courses from which you can choose including: “Exploring Black Holes General Relativity & Astrophysics” taught by MIT professor Edmund Bertschinger, “Science and Cooking: From Haute Cuisine to the Science of Soft Matter” taught by a team at Harvard, and “Introduction to Cosmology,” by James Bullock at UC Berkeley.
A word to the wise: These courses are the real thing, taught by real experts in real classroom settings with students who have completed the necessary prerequisites. Therefore, to have a hope in keeping your footing in Binney’s class, it’s important to have at least a basic understanding of calculus, linear algebra and differential equations as well as be comfortable with Greek letters.
There are MOOCs for those math subjects, too. The best part is that you can fast forward and rewind Binney and others as often as you like. What I wouldn’t give to have had that kind of control over my quantum mechanics professor!
So, how can the example of Schrodinger’s cat be expressed mathematically? That is a rather rigorous calculation and will have to wait for another day.