We use physics every day. The laws of motion and momentum govern our movements, and the law of gravity keeps us from floating away — but what about quantum physics? We hear the words used in popular media — it’s mentioned repeatedly in shows like “The Big Bang Theory,” but what do they actually mean? Let’s take a closer look at the field of quantum physics, and how scientists are able to study it.
What Is Quantum Physics?
Quantum physics is similar to standard physics. Classic physics focuses on ordinary nature, things we can see and touch without the need for additional tools. Think of Newton’s apple, when he allegedly discovered the theory of gravity.
Quantum physics is based on a theory called quantization, or the process of transitioning from an understand physical phenomena — like Newton’s apple — to something we can’t see or touch. In essence, quantum physics is the science of the smallest particles in the universe and how they interact with the things around them. Quantum physicists study subatomic particles — photons, electrons, neutrons, quarks, etc. — but how can you study something you can’t see?
Quantum physics, also known as quantum mechanics, made an appearance in the scientific communities in the early 1900s when Albert Einstein published his theory of relativity. However, this field can’t be attributed to any one scientist.
In 1900, a physicist named Max Planck found himself facing a dilemma. According to the laws of physics at the time, if a box was heated up in an environment where no light could escape, it would produce an infinite amount of ultraviolet radiation. At the time, scientists assumed light was a continuous wave. When heating the box didn’t work as they predicted, Planck started to think that light didn’t exist as a wave, but rather as small amounts of energy known as quanta.
He was right. Einstein later theorized that light existed as individual particles, which in 1926 were named photons.
Studying the Universe’s Smallest Particles
How can you study something that is too small for even the most powerful microscope to see? The technology actually dates back to the early 1800s during the discovery and development of the periodic table. Our first glimpse into subatomic particles didn’t come from physics, but rather from chemistry. The first subatomic particle we discovered was the electron, because of the discharge effects of electricity in some gases. Then came protons, the nucleus of the atom and neutrons.
The 1930s brought us the first particle accelerators, and while they were not as high-tech or advanced as the ones we use today, they enabled scientists of the time to accelerate proton beams and measure the size of an atom’s nucleus. Today’s accelerators work on the same principles, producing a beam of charged particles scientists can use to study other subatomic components. They can detect them directly or discover their presence because of the reaction of the charged particles.
The Quantum Uncertainty Principle
Of course, nothing is ever easy in quantum physics. In 1927, Werner Heisenberg of Germany theorized that it is impossible to measure both the position and the velocity of an object at the same time. This theory later became known as the Quantum or Heisenberg Uncertainty Principle, and is one of the foundations of modern quantum mechanics.
It doesn’t work for items we can see. You can easily tell the velocity and position of an apple falling from a tree — 5.8 meters per second squared, based on the law of gravity — but it’s not as easy to determine either of these things when you’re talking about a particle that’s impossible to view with the naked eye.
Remember Schrodinger’s thought experiment, in which a cat was in a box with poison? The cat is both alive and dead until it is observed to be one or the other. That applies to the Heisenberg Uncertainty Principle as well. Any attempt to measure the velocity or position of a subatomic particle will affect both measurements in such a way that no actual analysis is possible. The mere act of observation changes the outcome of the experiment.
This is what makes quantum physics so challenging as a field. Anything we learn is colored by the act of learning it — but that doesn’t mean we haven’t made any significant discoveries.
Recent Discoveries in Quantum Physics
Quantum physics has taken off in recent years. 2018, in particular, was a phenomenal year for scientific advancements. Scientists trying to create quantum computers managed to pack 18 qubits of information into six photons. We’ve discovered that life on this planet may rely on some form of quantum entanglement, with particles linked together at a subatomic level.
We’ve found that there are actually two types of water molecules — one where the hydrogen and oxygen atoms point in the same direction, and one where they’re pointing in opposite directions. Military radar technology may even be getting an upgrade thanks to quantum mechanics. By using entangled photons, scientists hope to create a stealth-busting radar that will notify them if they are being tampered with or encountering problems. This is based on the readings generated by photons back at base.
This is just a fraction of the amazing discoveries we’ve made in the last year alone.
The Future of Quantum Physics
We’ve barely scratched the surface of the quantum universe, and as new discoveries trickle in, they’re likely to alter our understanding of everything — from science to life itself. It’s an exciting time to be alive, and we can’t wait to see what new advances are on the horizon.