Solids, liquids, and gases are just the beginning.
Before scientists discovered the new state of matter last week, we were basically all used to just three states of matter. After all, during our daily lives we encounter some variety of solids, liquids and gases. Solids hold a definite shape without a container, liquids conform to the shape of their container, and gases not only conform to a container, but also expand to fill it.
And there’s variety amidst these three: A crystalline solid, for example, has all its atoms lined up in exactly the precise order in perfect symmetry, while a quasicrystal solid fills all its space without the tightly regulated structure. Liquid crystals, which make up the visual components of most electronic displays, have elements of both liquids and crystal structures, as anyone who has ever pushed the screen of their calculator can confirm.
Under standard conditions on Earth, solids, liquids and gasses are the vast majority of what a person will experience in life. But that doesn’t mean there’s not a whole lot more beneath the surface.
In 1856, the legendary British scientist Michael Faraday was studying thin sheets of gold leaf. Studying the properties of light and matter, Faraday was determined to make gold thin enough that it would be transparent to light. There wasn’t machinery in existence at the time that could make films of gold that small, so Faraday had to use chemicals.
While washing the gold in these chemicals, Faraday noticed that the action produced a faint ruby colored fluid. This mixture of chemicals and gold, called a colloid, had the ability to scatter light shone in its direction. Even though scientific instruments at the time couldn’t prove it, Faraday knew this light scattering was because of gold particles within the fluid. This was likely the first ever documentation of how a quantum state could have altering properties.
Quantum mechanics, quantum physics, and quantum computing study a wide variety of things, but they’re all focused on what isn’t noticeable to the naked eye. Faraday’s light-scattering gold particles were in a quantum state—the smallest they could possibly exist. Since the 1850s, the science and exploration of quantum states has, with a little bit of irony, grown tremendously, and has revealed things previously thought unimaginable. Take, for example, topological superconductivity, that aforementioned new state of matter.
Through quantum studies, space exploration, and several other fields, there have been several discoveries of new types of matter, such as the five that follow. Not all of them are useful, although some are quite practical. But they’ve all shown that existence is more than three states.
Something like the fifth Beatle of classical matter, plasma might often be forgotten, but it’s the most abundant state of matter in the universe. As described by NASA, plasma is “a mixture of electrons (negatively charged) and ions (atoms that have lost electrons, resulting in a positive electric charge).” It acts like a gas, except it also has the nifty trick of conducting electricity. It can also be affected by magnetic fields.
While most plasma is out of arm’s reach, lightning is a great example of how it interacts with Earth. A high-current electric discharge in air, an average lightning bolt has a peak temperature greater than 50,000 degrees Fahrenheit. At that heat, the lightning bolt’s atoms become ionized, turning into plasma.
People have also figured out how to artificially ionize gas, like in neon signs where the charged particles help complete an electrical circuit.
Bose–Einstein condensate (BEC) was discovered through a collaboration between between Indian physicist Satyendra Nath Bose and Albert Einstein, even though the two lived thousands of miles apart before the Internet.
In the early 1920s, quantum theory was a new field. Bose was teaching at the University of Dhaka and had grown dissatisfied with the then-current understanding of radiation. He wrote a paper studying the issue with a twist: He didn’t use any elements of classical physics. When the paper was rejected by journals, Bose turned to Einstein in a letter, even though the two scientists were strangers.
Einstein read over the paper and agreed with Bose’s findings. He used his influence to push for Bose’s publication in a prestigious journal. But that wasn’t all. Einstein kept thinking about Bose’s math, which said that indistinguishable particles could occupy discrete energy states.
In 1924, Einstein used Bose’s math to create a new form of matter, the BEC. At extremely low temperatures, barely above absolute zero, individual atoms would meld into a “superatom.”
And in 1995, a team of scientists proved him right.
“It’s like running in a hail storm so that no matter what direction you run the hail is always hitting you in the face,” said Carl E. Wieman, a scientist who helped discover the BEC, describing the phenomena. “So you stop.”
While a BEC is somewhat like an ice crystal forming in a pond, “it really is a new form of matter,” Wieman said. “It behaves completely differently from any other material.”
The particles identified in the BEC came to be known as “bosons” and are now seen as a fundamental part of matter. But there’s another type of quantum particle: fermions, which are named after Italian physicist Enrico Fermi. Because of how they spin, fermions cannot occupy the same quantum state within a quantum system at the same time.
Sounds simple enough, but the rules of physics are taken to an extreme when a star like a white dwarf is collapsing. The gravity is beyond belief. As gravity pulls the electrons closer and closer, and because they can’t exist, they can’t move any closer together at the quantum level. So, they have to move to higher states of energy.
That transition, which creates degenerate matter, is difficult to grasp. If the fermion is, for example, an electron, it can’t give up any electrons as an object in motion normally would. But its momentum is still present, known as “degeneracy pressure.” It also applies to protons and neutrons.
Degenerate matter allows dense stars like white dwarves to exist. Scientists theorize that it’s a near-perfect conductor of heat and resistant to natural laws of gravity, but have yet to see any. Luckily, a group of astronomers may have recently caught a neutron star getting shredded open by a black hole.
Quantum Spin Liquids
Yes, that’s a picture of a rock. It’s a copper-based mineral known as Herbertsmithite, named after British mineralogist Herbert Smith. It’s found in Chile, Iran, Arizona, and Greece. It’s not a new type of matter, but it could be related to one.
Quantum mechanics helps scientists understand many fundamental forces, like magnetism. Quantum physics looks at sub-atomic particles like electrons and studies how they work. These particles all have a property scientists refer to as “spin.” This spin is a rough analogy, as the particles don’t spin like baseballs. Sub-atomic spin can make every single electron in an object act like a magnetic needle, with all of them moving in the same direction.
In most magnets and magnetic fields, spin results in a stable formations with all electrons in order. However, they’re what’s known as “frustrated magnets.”
For frustrated magnets, “the arrangement of electron spins prevents them from forming an ordered alignment, and so they collapse into a fluctuating, liquid-like state,” explains Lucy Clark, a Materials Chemist at the School of Chemistry at the University of St. Andrews at the time of writing. That’s known as a quantum spin liquid, a term first coined by American physicist Philip Warren Anderson in 1972.
“In a true quantum spin liquid, the electron spins never align, and continue to fluctuate even at the very lowest temperatures of absolute zero, at which the spins in other magnetic states of matter would have already frozen,” she says.
This is where Herbertsmithite comes into play. Scientists theorize that a quantum spin liquid state exists within the frustrated magnetic layers of copper ions. The challenge is getting to it. A team at the Oak Ridge National Laboratory, based in Tennessee, first showed a quantum spin liquid in nature in 2016.
It’s fitting to end our list with the oldest known matter. Quark-gluon plasma (QGP) only existed naturally for a few millionths of a second after the Big Bang. During that incredibly small period of time, the universe consisted entirely of a soup of quarks (theoretical subatomic particles carrying a fractional electric charge) and gluons, which “glue” quarks together.
Then, the universe began to cool, and the QGP turned into protons and neutrons, which turned into everything in existence.
“It’s believed to correspond to the state of the universe shortly after the Big Bang,” Quan Wang, a University of Kansas postdoc researcher working with the team at CERN, the European Organization for Nuclear Research said in a press statement in 2015. “The interaction … within the quark-gluon plasma is strong, which distinguishes the quark-gluon plasma from a gaseous state where one expects little interaction among the constituent particles.”
While working with CERN, Wang studied QGP matter with the Large Hadron Collider, which crashes protons with lead nuclei into each other at high energy. His team was able to recreate QGP by essentially melting the protons into a tiny fireball, collapsing them all into their primordial form.
But just because Wang’s team was able to recreate QGP doesn’t mean they understand it or its capabilities.
“While we believe the state of the universe about a microsecond after the Big Bang consisted of a quark-gluon plasma, there is still much that we don’t fully understand about the properties of quark-gluon plasma,” Wang said.
“One of the biggest surprises of the earlier measurements at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory was the fluid-like behavior of the quark-gluon plasma. Being able to form a quark-gluon plasma in proton-lead collisions helps us to better define the conditions needed for its existence.”
This article was written by David Grossman and was published by Popular Mechanics on 19/08/2019
Images: Pixabay and Unslash