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How do I get started in learning quantum mechanics?

Videos on the Youtube channel “Looking Glass Universe” provide the clearest intro to quantum mechanics that I’ve found. They don’t require math nor a prior knowledge of physics, and they take it slow. However, they really get you into the midst of quantum mechanics. It’s not a light once-over. Of course, start with #1 and take them in sequence. They’re each about 10 minutes and there are about 14 of them.

For more of a light once-over, documentaries hosted by Brian Greene on Youtube are excellent. He’s a quantum physicist and a noted science writer.

Good beginning book on quantum mechanics is Fields of Color by Rodney Brooks.

I’m assuming here that you already know the basics of Newtonian physics. If not, study these first. The Physics Classroom is an excellent free on-line course on Newtonian physics. It’s step-by-step and gives practice problems. Khan Academy also has excellent free lessons on Newtonian physics.

Whenever I didn’t understand something in a particular video or book on quantum mechanics, I found videos or on-line articles about that particular thing until I had more understanding of it.

I’m writing definitions of quantum physics jargon for people who are interested in quantum physics but don’t want to dive into the math of it. It’s the definitions and the illustrations and examples that I wish I had when I was first watching these videos and floundering around. I’m hoping that it will help others.

Can you explain the essence of quantum mechanics in three sentences?

Quantum mechanics is the study of the tiniest components of matter and energy. The components of matter are the tiny bits inside the atom: protons, neutrons, electrons, etc. The components of energy are, in the case of light, photons. Other types of energy have other components. These components follow laws different to those of everyday objects like tables and chairs;. For example, they can influence each other at great distances faster than the speed of light. They can also act as though they fill all of a space, that is, are everywhere at once. They operate as if they were vibrations in a different reality that underlies the reality that our senses are aware of.

We can’t see the tiniest components of matter and energy. Our eyes cannot perceive the quantum level of reality. Nor do we have microscopes sufficiently powerful. But this animation is suggestive of how such components might look if we could see them.

 

 

How can we tell when descriptions of quantum mechanics are woo-woo and not scientific?

[This is my answer to a question on a website that others answered also.] Many of the answers to your question express the view that quantum physics is a mathematical theory that can be verified by experiment. Of course, this is true. However, some of the answers suggest that if the person discussing quantum physics is not writing math equations or reporting on experimental results, they’re talking woo. This is not true.

Many populizers of quantum physics, such as Brian Greene and Stephen Hawking, are themselves physicists. When they address lay audiences, they usually do not write math equations. They may or may not report on the details of experimental results. They are attempting to communicate the theory of quantum physics and important implications to a lay audience.

While a lot of the math of quantum physics is understood by physicists and a lot of experiments have been done, there is a great deal more to know about both. This is an evolving science; more is being learned every day. In such a situation, it is premature to say that we understand what can be said legitimately about quantum physics and what is woo.

Theoretical quantum physicists do math and attempt to interpret the math and the experimental results so that they can envision new experiments. This has been the role of important physicists like Einstein and John Bell. Theoretical interpretations allow quantum physics to progress just as experiments do.

Currently, there are many different theoretical interpretations of quantum physics. They mostly SOUND like woo. For example, the Many Worlds hypothesis proposes that innumerable universes are created be quantum events. The Bohmian approach proposes that every event is connected with every other event in the universe, thus explaining quantum entanglement.

Yet, serious physicists propose these kind of hypotheses and work on math regarding them. These are the easiest ones to describe—other interpretations are as weird when you get down into the details. And I’m including the Copenhagen (orthodox) interpretation as being weird because it depends on a very weird view of what reality is. That’s why Einstein challenged it for decades. “Weird” here does not mean woo and does not mean wrong. It simply means unfamiliar to us who live in the world of chairs and tables and don’t deal with electrons and photons on a daily basis.

It is easy to attack people who rely on quantum physics for some of their far-out philosophies. But when quantum physicists, themselves, propose Many Worlds or universal connectedness, one wonders who is calling the kettle black.

So, bottom line, I don’t think there is a way to distinguish between woo and serious physics without a heavy background in math and physics. Not yet. Quantum physics is currently an anarchy of interpretations, with each physicist either turning away from any interpretation at all or supporting their own preferred view. This is not a good time to make fun of someone else’s interpretation or of a philosophy based on an interpretation that one isn’t familiar with and, therefore, one supposes could not possibly have scientific support.

he answers to your question express the view that quantum physics is a mathematical theory that can be verified by experiment. Of course, this is true. However, some of the answers suggest that if the person discussing quantum physics is not writing math equations or reporting on experimental results, they’re talking woo. This is not true.

Many populizers of quantum physics, such as Brian Greene and Stephen Hawking, are themselves physicists. When they address lay audiences, they usually do not write math equations. They may or may not report on the details of experimental results. They are attempting to communicate the theory of quantum physics and important implications to a lay audience.

While a lot of the math of quantum physics is understood by physicists and a lot of experiments have been done, there is a great deal more to know about both. This is an evolving science; more is being learned every day. In such a situation, it is premature to say that we understand what can be said legitimately about quantum physics and what is woo.

Theoretical quantum physicists do math and attempt to interpret the math and the experimental results so that they can envision new experiments. This has been the role of important physicists like Einstein and John Bell. Theoretical interpretations allow quantum physics to progress just as experiments do.

Currently, there are many different theoretical interpretations of quantum physics. They mostly SOUND like woo. For example, the Many Worlds hypothesis proposes that innumerable universes are created be quantum events. The Bohmian approach proposes that every event is connected with every other event in the universe, thus explaining quantum entanglement.

Yet, serious physicists propose these kind of hypotheses and work on math regarding them. These are the easiest ones to describe—other interpretations are as weird when you get down into the details. And I’m including the Copenhagen (orthodox) interpretation as being weird because it depends on a very weird view of what reality is. That’s why Einstein challenged it for decades. “Weird” here does not mean woo and does not mean wrong. It simply means unfamiliar to us who live in the world of chairs and tables and don’t deal with electrons and photons on a daily basis.

It is easy to attack people who rely on quantum physics for some of their far-out philosophies. But when quantum physicists, themselves, propose Many Worlds or universal connectedness, one wonders who is calling the kettle black.

So, bottom line, I don’t think there is a way to distinguish between woo and serious physics without a heavy background in math and physics. Not yet. Quantum physics is currently an anarchy of interpretations, with each physicist either turning away from any interpretation at all or supporting their own preferred view. This is not a good time to make fun of someone else’s interpretation or of a philosophy based on an interpretation that one isn’t familiar with and, therefore, one supposes could not possibly have scientific support. It’s always good to keep in mind those who mocked and vilely threatened poor souls like Galileo who believed outlandish theories like the earth travels around the sun.

However, it’s an exciting time to try to understand as much as possible of the math, experimental results, and theoretical interpretations. With enough study, one can begin to draw one’s own conclusions about what is woo and what has theoretical, mathematical, and experimental support.


What is the difference between a photon and a quantum?



April 13, 2019


[This article is under construction.]  A photon is a type of quantum. So, it’s like the difference between a blue jay (photon) and a bird (quantum). If this answers your question, you can stop reading. If you want to know more about what a photon and a quantum really are,… Read more


Why does the Born Rule predict quantum probabilities?



March 14, 2019


There’s both a mathematical explanation and an explanation based on the nature of reality. First, the mathematical explanation: Let’s take the example of the Double Slit Experiment. A laser shoots photons one-at-a-time through the two slits of a screen towards a photographic plate. The wave function is the equation that… Read more


How do we know a quantum particle is in a superposition if detecting the particle will destroy the superposition?



March 13, 2019


It’s not possible to KNOW that the particle is in a superposition of states since we can’t observe the superposition. The superposition idea is trying to explain what must be happening in the real world given that Schrodinger’s Wave Equation works. Schrodinger’s Wave Equation (and later upgrades like the equations of… Read more


What are some good online resources that can help me understand physics better?



March 9, 2019


The Physics Classroom and Khan Academy both have excellent free on-line courses on physics, starting from the beginning. They’re step-by-step and give practice problems. On Khan Academy, if you sign in, it will keep track of your progress. It also gives “awards” like badges for good progress. Both websites are excellent. Khan… Read more


How do I get started in learning quantum mechanics?



March 7, 2019


Videos on the Youtube channel “Looking Glass Universe” provide the clearest intro to quantum mechanics that I’ve found. They don’t require math nor a prior knowledge of physics, and they take it slow. However, they really get you into the midst of quantum mechanics. It’s not a light once-over. Of… Read more


Can quantum mechanics be understood? Does it make logical sense?



February 26, 2019


Quantum mechanics is logical. By logical, I mean that the assumptions, the principles, the equations, and the empirical data all fit together. They don’t contradict each other. However, quantum mechanics (QM) does not fit with the assumptions and principles of classical physics (physics prior to 1900 that we learned in… Read more

How can I learn Quantum Mechanics?

I will start by saying that I understand the math of Quantum Mechanics (QM) only in a highly conceptual way. Understanding the math to the point that one can calculate quantum mechanics problems, requires familiarity with matrix math and partial differential equations, and more. This requires several years of calculus.

However, I do have a basic conceptual understanding of QM. I understand its logic, which is my interest. If I were to be interested in using QM to work in electronics or as a physicist, I would need to take several years of calculus, classical physics, and QM. But that is not my interest.

I got interested in QM about 3 years ago. I’m interested in its implications for the nature of reality. But I didn’t have sufficient math nor classical physics to take a course in it. I had high school chemistry (no physics at all) and one semester of college calculus.

I started by reading biographies of quantum physicists, which usually contain some highly conceptual info about QM. I also watched beginner’s Youtube video lectures and animations. The best is a series called “Looking Glass Universe.” Even though I didn’t understand a lot of it, I would watch and re-watch, look up words, look for easier videos, anything needed to make progress.

Then, I studied four physics courses for non-scientists—meaning courses with very little math. These emphasized modern physics (QM and relativity). One was a textbook, Physics by Art Hobson, published by Pearson Custom Library, available on Amazon. The next two were audio books in The Great Courses series: Modern Physics and also Particle Physics for Non-Physicists. I listened to these while doing housework and cooking. They probably would each take a semester each if they were college courses. The fourth course was a DVD series by the Teaching Company: The Theory of Everything by Dr. Don Lincoln.

In between these courses, I read many books on QM for lay readers. The best of these were Quantum, A Guide for the Perplexed by Jim Al-Khalili and Understanding Our Unseen Reality by Ruth E. Kastner. They’re useful once you’ve read some biographies and looked at a lot of Youtube videos for beginners. I got something out of all the books that I read or listened to—the understanding slowly builds.   

I also reviewed all my earlier math with Khan Academy lessons—I had forgotten most of second year algebra, trig, and I had never learned matrix math. Then, I completed re-doing the first semester of calculus with an on-line free course that Ohio State University offers. Now, I’m into the second semester of calculus. I really enjoy math but have only average ability at it.

While I don’t attempt the math of QM, I find that having some understanding of calculus is quite helpful. I’ve pieced together a basic understanding of the Schrodinger’s Equation (a key QM equation), though I’m several years of calculus away from being able to calculate with it.

When I can’t understand something, I look up words on the Internet, watch videos about it on Youtube, and re-listen to audio books and re-listen and re-listen. I’ve listened to some of my audio book lectures maybe 15 times (I do a lot of housework and cooking!).

I think younger people make brain connections far faster than us oldsters (I’m 71). But I think that re-listening or re-reading, so long as one is looking up the words, is key. For me, the conceptual understanding comes slowly, and that is always what I’m going for.

I’m currently writing an encyclopedia of quantum physics for lay audiences (like myself) www.QuantumSkylight.com. That forces me to really understand—or I can’t write it. I’m learning more every day as I work on the encyclopedia.