“Anyone who thinks they can talk about quantum mechanics without getting dizzy hasn’t yet understood the first word of it” Niels Bohr.
There is no better way to start a talk about Quantum physics than with a quote from the father of it all, Niels Bohr.
The titles Quantum Physics, Quantum Realm, Quantum Reality are no longer strange words. What a lot of people shriveled at the thought of many years ago is becoming quite popular. By reason of necessity, the few are becoming the many. With a world that is becoming smaller every day, and the tirelessness of sci-fi movies, we can expect that the average American man has a thing or two to say about the quantum realm.
Nonetheless, a lot of people lack proper understanding as to what it really is and how it actually works. For a lot of people, it is complicated stuff and maybe even supernatural. If you have ever watched an episode of The Big Bang Theory, then you would know that it’s a complex subject- so complex that even comedy could not make it any easier. Like David Wallace, Professor of Philosophy at the University of Southern California, author of The Emergent Multiverse, said, even the basic concepts of quantum physics will make your mind hurt.
You will therefore understand when I say I have undertaken a rather enormous task. The task of making quantum physics as simple as possible. It will contain the right amount of science-y terminology – so you can have something to say at your next high school reunion- but it will be simple enough to grasp the very basic idea.
So, wish me luck!
A Brief History of Physics
Physics is a science. Obvious right? Physics is, however, not just a science of the abstract and of whiteboards, physics is a science of everyday life. When you consider how you- as every other human- live, you will realize that we are all participants in this science. Whether you are just lifting an object from the floor or jogging around the park, or viewing this article, the principles of physics are always at play in our everyday lives.
Another thing to note is that Physics is first and foremost a science of discovery. What I mean is this: The principles that make up the body of knowledge called Physics are not invented, but rather discovered. The universe is always a functioning reality. What physics does is discover how the universe and reality as a whole work.
With these two in mind let us look a brief history of this science.
The story begins in the 1600s with the birth of classical physics which is basically the way we understand the macroscopic world- the world we can see.
As man continued to investigate the structure of our world, the evidence provided by large things became too small. So, we began to look at smaller things to see the bigger picture. That’s how the exploration into the quantum realm began. It was driven by a need to understand.
The history of quantum physics really began in 1900 and went through 30 years of immense growth. By 1913, so much progress had been made that renowned physicists made the distinction between the theories of quantum physics and classical physics.
It is actually worthy of note, however comedic it might sound, that one of the most important breakthroughs in this sphere didn’t come until the Double Slit Experiment which happened to be an accident. It was published by Davisson and Germer in 1927 but believed to have been first performed by Thomas Yung in 1802.
What the experiment provided was proof that light and other states of matter can act as both a wave and a particle at the same time. Here is what it means. A wave is like energy in motion. The energy is all along the wave, there is no specific location. A particle can however only be in one place at the same time. So how can a single thing be both a wave (appearing in many different places) and at the same time, a particle (appearing in only one place)? Now you get why it’s so intriguing.
For example, let’s say you shoot sticky pellets through a wall that has two holes to hit a wall behind it. Two possible things can happen. Some of the pellets will bounce off the parts of the first wall that do not have the hole. The other pellets that happen to pass through the hole will go on ahead and form the shape of the two holes on the wall behind.
That’s straightforward right?
However, what happens when you use atomic particles instead of pellets is that other shapes are also made. So instead of having two pellet (particle) formed shapes, we end up with four! How?!
The experiment was repeated again using water flowing through a double slit barrier-a barrier with two openings. The same phenomenon repeated itself, providing stronger evidence that there is a connection between waves and particles.
According to these experiments, the waves are the possible locations for the particle to be in. Now since it is possible for matter to exist in these two states- as a particle and as a wave- how do we determine the specific location of a particle along the entire wave?
In 1920, Bohr came up with an explanation of probabilities. It proved to be the simplest explanation of the results. The light (pellet shaped) areas are where there is a high probability of finding the particle, while the grey areas are where there is a lower probability, and the black areas represent no probability. This is important because it means a particle can be in several places at once but can only be in one place at the time of observation. In other words, the outcome of reality can be altered by measurement.
So how do we make enough sense of these things to apply them to our everyday experience?
Well, it begins with measuring these probabilistic experiences to find out what is closest to the truth.
For this, Niels Bohr (with contribution from Werner Heisenberg, Max Born and other physicists) used something called the Copenhagen Interpretation of quantum mechanics.
It is the first general attempt to understand the way the atomic world works.