Quantum Physics for Beginners

Quantum Mechanics for Beginners; A fun-filled introduction to Quantum Mechanics

1. Quantum Mechanics for Beginners

— an introduction —

How the Princess began to Feel the Pea

Science is exciting because it is always in trouble. No matter how excellent a theory is, it always misses some point or other. Even our most precious ideas about the universe are not able to explain everything; there's always a blind spot. And when the hopeful folks zoom in on that blind spot it pretty much always turns out to be a lot larger than anybody thought, and all of us a mere bunch of naive beginners.

At the end of the eighteenth century the blind spot of regular mechanics (=the library of dogmas that teach the ins and outs of objects moving and colliding) covered the behavior of very small objects, such as electrons, and the behavior that light caused when it hit small things like electrons.

Light had been a mystery for centuries. Some experiments proved beyond the shadow of a doubt that light was waves. Some other experiments proved beyond the shadow of a doubt that light was particles. The truth about light was obviously hidden and it wasn't until 1900 that people began to understand that there was something very weird about the world of the small. Something that required a complete revision of understanding.

It was decided that the world of the very small was governed by rules that were different from the rules that governed the world we can see, and regular (or classical) mechanics begat Quantum Mechanics. And that unanticipated breach in mechanics spawned this very important rule:

Hold that thought (1) Individual quantum particles are subjected to a completely different law than the law to which large objects made from quantum particles are subjected.

The introduction of the quantum

Max Planck

Introduction of

the Quantum

The Quantum Mechanical era commenced in 1900 when Max Planck postulated that everything is made up of little bits he called quanta (one quantum; two quanta). Matter had its quanta but also the forces that kept material objects together. Forces could only come in little steps at the time; there was no more such a thing as infinitely small.

Albert Einstein

King of Beginners

Albert Einstein took matters further when he successfully described how light interacts with electrons but it wasn't until the 1920's that things began to fall together and some fundamental rules about the world of the small where wrought almost by pure thought. The men who mined these rules were the arch beginners of Quantum Mechanics, the Breakfast Club of the modern era.

Names like Pauli, Heisenberg, Schrödinger, Born, Rutherford and Bohr still put butterflies in the bellies of those of us who know what incredible work these boys — as most of them where in their twenties; they were rebels, most of them not even taken serious — achieved. They were Europeans, struck by the depression, huddled together on tiny attics peeking into a strange new world as once the twelve spies checked out the Promised Land. Let all due kudos abound.

Believing the unbelievable

One of the toughest obstacles the early Quantum Mechanics explorers had to overcome was their own beliefs in determinism. Because the world of the small is so different, people had to virtually reformat the system of logic that had brought them thus far. In order to understand nature they had to let go of their intuition and embrace a completely new way of thinking. The things they discovered were fundamental rules that just were and couldn't really be explained in terms of the large scale world. Just like water is wet and fire is hot, quantum particles display behavior that are inherent to them alone and can't be compared with any material object we can observe with the naked eye.

One of those fundamental rules is that everything is made up from little bits. Material objects are made up of particles, but also the forces that keep those objects together. Light, for instance, is besides that bright stuff which makes things visible, also a force (the so-called electromagnetic force) that keeps electrons tied to the nuclei of atoms, and atoms tied together to make molecules and finally objects. In Scriptures Jesus is often referred to as light, and most exegetes focus on the metaphorical value of these statements, but as we realize that all forms of matter are in fact 'solidified' light (energy, as in E=mc2) and the electromagnetic force holds all atoms together, the literal value of Paul's statement "and He is before all things, and in Him all things hold together" (Colossians 1:17) becomes quite compelling.

Particles are either so-called real particles, also known as fermions, or they are force particles, also known as bosons.

Quarks, which are fermions, are bound together by gluons, which are bosons. Quarks and gluons form nucleons, and nucleons bound together by gluons form the nuclei of atoms.

The electron, which is a fermion, is bound to the nucleus by photons, which are bosons. The whole shebang together forms atoms. Atoms form molecules. Molecules form objects.

Everything that we can see, from the most distant stars to the girl next door, or this computer you are staring at and yourself as well are made up from a mere 3 fermions and 9 bosons. The 3 fermions are Up-quark, Down-quark and the electron. The 9 bosons are 8 gluons and 1 photon. Like so:

Quanta, which form → Atoms, which form → Molecules, which form → Objects

But the 3 fermions that make up our entire universe are not all there is. These 3 are the survivors of a large family of elementary particles and this family is now known as the Standard Model. What happened to the rest? Will they ever be revived?

We will learn more about the Standard Model a little further up. First we will take a look at what quantum particles are and in which weird world they live.

(If you plan to research these matters more we have written out the most common quantum phrases in a table for your convenience. Have a quick look at it so that you know where to find it in case you decide you need it).

Go to the next chapter:

Big Rules for Small Particles →

Quantum physics

What is quantum physics? Put simply, it’s the physics that explains how everything works: the best description we have of the nature of the particles that make up matter and the forces with which they interact.

Quantum physics underlies how atoms work, and so why chemistry and biology work as they do. You, me and the gatepost – at some level at least, we’re all dancing to the quantum tune. If you want to explain how electrons move through a computer chip, how photons of light get turned to electrical current in a solar panel or amplify themselves in a laser, or even just how the sun keeps burning, you’ll need to use quantum physics.

The difficulty – and, for physicists, the fun – starts here. To begin with, there’s no single quantum theory. There’s quantum mechanics, the basic mathematical framework that underpins it all, which was first developed in the 1920s by Niels Bohr, Werner Heisenberg, Erwin Schrödinger and others. It characterises simple things such as how the position or momentum of a single particle or group of few particles changes over time.

But to understand how things work in the real world, quantum mechanics must be combined with other elements of physics – principally, Albert Einstein’s special theory of relativity, which explains what happens when things move very fast – to create what are known as quantum field theories.

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Three different quantum field theories deal with three of the four fundamental forces by which matter interacts: electromagnetism, which explains how atoms hold together; the strong nuclear force, which explains the stability of the nucleus at the heart of the atom; and the weak nuclear force, which explains why some atoms undergo radioactive decay.

Over the past five decades or so these three theories have been brought together in a ramshackle coalition known as the “standard model” of particle physics. For all the impression that this model is slightly held together with sticky tape, it is the most accurately tested picture of matter’s basic working that’s ever been devised. Its crowning glory came in 2012 with the discovery of the Higgs boson, the particle that gives all other fundamental particles their mass, whose existence was predicted on the basis of quantum field theories as far back as 1964.

Conventional quantum field theories work well in describing the results of experiments at high-energy particle smashers such as CERN’s Large Hadron Collider, where the Higgs was discovered, which probe matter at its smallest scales. But if you want to understand how things work in many less esoteric situations – how electrons move or don’t move through a solid material and so make a material a metal, an insulator or a semiconductor, for example – things get even more complex.

The billions upon billions of interactions in these crowded environments require the development of “effective field theories” that gloss over some of the gory details. The difficulty in constructing such theories is why many important questions in solid-state physics remain unresolved – for instance why at low temperatures some materials are superconductors that allow current without electrical resistance, and why we can’t get this trick to work at room temperature.

But beneath all these practical problems lies a huge quantum mystery. At a basic level, quantum physics predicts very strange things about how matter works that are completely at odds with how things seem to work in the real world. Quantum particles can behave like particles, located in a single place; or they can act like waves, distributed all over space or in several places at once. How they appear seems to depend on how we choose to measure them, and before we measure they seem to have no definite properties at all – leading us to a fundamental conundrum about the nature of basic reality.

This fuzziness leads to apparent paradoxes such as Schrödinger’s cat, in which thanks to an uncertain quantum process a cat is left dead and alive at the same time. But that’s not all. Quantum particles also seem to be able to affect each other instantaneously even when they are far away from each other. This truly bamboozling phenomenon is known as entanglement, or, in a phrase coined by Einstein (a great critic of quantum theory), “spooky action at a distance”. Such quantum powers are completely foreign to us, yet are the basis of emerging technologies such as ultra-secure quantum cryptography and ultra-powerful quantum computing.

But as to what it all means, no one knows. Some people think we must just accept that quantum physics explains the material world in terms we find impossible to square with our experience in the larger, “classical” world. Others think there must be some better, more intuitive theory out there that we’ve yet to discover.

In all this, there are several elephants in the room. For a start, there’s a fourth fundamental force of nature that so far quantum theory has been unable to explain. Gravity remains the territory of Einstein’s general theory of relativity, a firmly non-quantum theory that doesn’t even involve particles. Intensive efforts over decades to bring gravity under the quantum umbrella and so explain all of fundamental physics within one “theory of everything” have come to nothing.

Meanwhile cosmological measurements indicate that over 95 per cent of the universe consists of dark matter and dark energy, stuffs for which we currently have no explanation within the standard model, and conundrums such as the extent of the role of quantum physics in the messy workings of life remain unexplained. The world is at some level quantum – but whether quantum physics is the last word about the world remains an open question.

Quantum Physics for Beginners

The truth is: When you look at it from an external point of view, the term Quantum Physics can be quite intimidating.

It is very complex and sometimes even professional physicists have a hard time trying to find their way around quantum physics, as it can seem quite counter intuitive. But even if it is difficult and complex to understand, it is nowhere close to being incomprehensible. There are a few key concepts of Quantum Physics, around which the whole subject revolves. If you know and understand these concepts, then you’ll find that it is very easy to understand how quantum physics functions.

First of all, you need to know that everything within the universe is made up of waves and particles. Yes, both of them at the same time. This is called the dual nature of substances. This seems quite crazy, and hard to believe, but both of these conclusions have been derived from numerous scientific experiments.

The second thing that you must understand, and accept is that when it comes to quantum physics, it is almost impossible to predict the exact result of an experiment on a quantum system. There can only probability, no certainty, leading us to the conclusion that quantum physics is probabilistic.

And last, but not the least, you must understand that quantum physics is very small, more often than not. This means that the study of quantum mechanics is well observed when the subject particles are extremely small. This is due the fact that quantum effects that are involved in the processes get smaller as the objects increase in size. As a result, quantum behaviors are hard to find.

Buy: Quantum Physics for Beginners, a beginner’s guide to unravel the basic mysteries of quantum physics, and a comprehensive course to help people understand it better.

Quantum Physics is an integral part of our lives and it is extremely important for us to have at least the basic knowledge on the subject. Most of the people struggle with it as there are scarcely any books on the topic that is compatible with the needs and demands of people who are just starting out as physicists, and need a simple guide to understand the concepts.

The goal of the audiobook is simple: To help people have a better understanding of quantum physics in the most simplest of ways possible.

You will also learn:

Relation between waves and particles

Why Max Planck is called the father of Quantum Physics

Laws of quantum physics

Quantum field theory

Einstein’s theory of relativity

Importance of the Hydrogen atom

Basics on angular momentum on a quantum level

Would you like to know more?

Buy the audiobook, Quantum Physics for Beginners by Brad Olsson to have a good knowledge of quantum physics and mechanics.