Our A Level Students have just finished studying Quantum Physics, here's an overview.
Quantum physics deals with the quantized nature of energy and matter as well as their interchangeable relationship – everything is made up of energy oscillating at differing frequencies.
"If you want to find the secrets of the universe, think in terms of energy, frequency and vibration.”
- Nikola Tesla.
Above: The Orion Nebula
Just over a century ago J.J Thomson experimentally identified the fundamental particle we call an electron. A few decades later electrons in motion were observed to behave like waves, rather than solid particles. This discovery lead to questions about whether or not electrons, which were thought to be tiny solid sphere's up until this point, were in fact some kind of wave.
Later experiments into the interaction between light and matter, particularly the electron, showed some other very surprising results (upon which much of modern technology now depends). One discovery was that light of sufficiently high frequency could produce a charge on the surface of certain metals. This property gave rise to a profoundly useful technology, as the built up charge could be used to produce voltage and thus induce electric current. This behaviour became known as the photoelectric effect, and is what Albert Einstein won the 1921 Nobel Prize in Physics for. It is this phenomena which allows modern photovoltaics, or solar cells, to produce electrical energy.
What is Light?
Light is a periodic oscillation of energy. There are many forms of light, most of which we can't see, but all forms of light have some energy. Light is effectively a rippling of an otherwise invisible energetic field of the universe (also known as the electromagnetic field). The rippling of this field sometimes produces visible light, which is what we see with our eyes. Interestingly these particular oscillations in the electromagnetic field make up less than 0.01% of all known forms of light (electromagnetic waves). Thus, human beings are profoundly blind to over 99.99% of the universe!
Despite most light being invisible to our eyes we can study it with special devices such as spectrum analysers or oscilloscopes. These instruments and others show us that the various waves of light can combine together and interfere with each other, producing different combinations and patterns, much like the ripples in a pond or upon the sea. We call this process "superposition", and only waves should be able to do this. This is also what gives the experience of harmony and chords in music.
"I think I can safely say that nobody understands quantum mechanics." - Richard Feynman
Above: Visual Representations of the quantum mechanical view of hydrogen
Wave - Particle Duality
In quantum mechanics we discover that what was previously thought of as solid particles should instead be considered an energetic wave, or a vibrating form of energy, because of the way it behaves in certain scenarios. At the quantum level a particle can have its own wave like properties (for example the de Broglie wavelength which we study in A Level Physics) despite our expectations for particle behaviours.
In other cases a particle does indeed behave as if it were a solid platonic sphere, or simple particle. We also study this through the wave - particle duality part of the A Level physics course at Atherton, and the class have handled these ideas remarkably well - even if they seem too strange for Nobel Laureates!
“If you think you understand quantum mechanics, you don't understand quantum mechanics.”
- Richard P. Feynman, Nobel Prize Winner in Physics (1965, Quantum Electrodynamics)
"It followed from the special theory of relativity that mass and energy are both but different manifestations of the same thing - a somewhat unfamiliar conception for the average mind."
- Albert Einstein, Nobel Prize Winner in Physics (1921, Photoelectric Effect)
In our current topic of Nuclear Physics, Atherton School's year 13 A Level students are discovering that matter and energy are in fact interchangeable, and can be related mathematically using Einstein's famous equation for mass energy equivalence.
"Furthermore, the equation E is equal to m c-squared, in which energy is put equal to mass, multiplied by the square of the velocity of light, showed that very small amounts of mass may be converted into a very large amount of energy and vice versa. The mass and energy were in fact equivalent, according to the formula mentioned above. This was demonstrated by Cockcroft and Walton in 1932, experimentally."
- Albert Einstein
Einstein struggled for many years with quantum mechanics, famously stating that "God does not play dice". He said this in opposition to Werner Heisenberg's uncertainty principle, which defined things that we simply cannot know with experimental certainty, because the act of measurement and observation itself will affect the observed entity.
While it is entirely possible that Einstein is correct in his assertion that quantum physics misunderstands the way our universe is governed or set into motion, it is certainly true that there are things in physics which we cannot yet know. Some of this is covered by Heisenberg's uncertainty principle, and others exist within the strange world of "black holes" or singularities - from which not even light can escape.
A large part of modern physics in the last century has been attempting to reconcile Einstein's big ideas of space-time and relativity with the subatomic world of quantum theory. So far there has been little significant progress in the unification of these different theories, but they have both been greatly utilised and proven individually. One day someone will bring physics into harmony again. Perhaps one of us!
Today there are several attempts in physics to unify explanations for the behaviour of both the relativistic and quantum worlds. One of these is expressed through the mathematically complex "string theory".
Above: Brian Greene, Professor of Physics and Mathematics at Columbia University, on String Theory
Though we are yet to reconcile major disagreements between quantum mechanics and larger scale relativistic physics, we are beginning to understand something profoundly beautiful within all of science. The realisation that matter and energy are equivalent invites a deeper contemplation for what we each are and for what this universe is as a whole. It becomes harder to see where a distinction can truly be made between an individual organism and the universe it forms a part of. Are we not the universe?
Quantum entanglement and other interesting discoveries leads us to question our connection beyond space and time itself, in an energetic dimension, toward each other and this cosmos. We find ourselves part of an energetic ocean of life, just one of many lives, in a living universe of varied perspectives.
Whatever the discoveries that we make going forward, we hope to grow in knowledge every day.
"Quantum physics thus reveals a basic oneness of the universe.”
- Erwin Schrödinger, Nobel Prize Winner in Physics (1933, Quantum Mechanics)