What is Knotted Chiral Meta Matter?
At the International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM²), we are pioneering a new research field called ‘Knotted Chiral Meta Matter.’ While the possible directions under this new field are vast, our goal is to focus on those that have the highest potential to contribute to sustainability, such as Climate Action, Responsible Consumption and Production, and other goals set laid out in the UN Sustainable Development Goals.
To help explain the field, let’s break down “Knotted Chiral Meta Matter,” which is made by connecting three distinct concepts:
- Knot
- Chiral
- Meta Matter
Read below to learn more about each of these concepts, Knotted Chiral Meta Matter as a whole, and how this new field and our institute pushes the boundaries of science and contributes to sustainability.
What is a Knot?
You may easily recognize a knot in your shoelace, but there is actually an entire field of mathematics called knot theory which studies ‘knots’ that are a bit different than the one in your shoelaces. In math, a knot refers to the shape formed when a string is tied into a closed loop, so in that definition, even a rubber band is a knot – it’s the simplest knot and mathematicians call it the “unknot.”
Mathematicians study knots by bending or stretching them without cutting, breaking, or adding strings, which in math is called a continuous deformation. In knot theory, two knots are considered the same if one can be deformed into the other. While proving that two knots are the same can be easy, proving they are truly different can be extremely difficult because their shapes can change endlessly through deformation. This is what makes knot theory so fascinating. The mathematicians who study knots fall under a broader umbrella of mathematics, called topology, which studies the properties of shapes and spaces that are unchanged by continuous deformation.
While mathematicians study knots as mathematical entities and allow us to contemplate the deceptively simple yet profound question: “What does it mean to be knotted?,” knot theory also connects to various scientific fields, including tangled molecules and proteins, the structure of DNA, and complex arrangements in liquid crystal molecules.
What is Chiral?
One of the easiest ways to visualize chirality is to look at our hands. Firstly, our two hands are mirror images of one another – if you’d like to check, you can put your right hand on a mirror and see that the reflection looks just as if it were your left hand.
The interesting thing about your hands is that it is very easy to tell a right hand from a left hand. If you try to stack your hands, you can see that your thumbs are on opposite sides, and there is no way to rotate or translate one hand to make it perfectly match with the other.
In short, chirality, or handedness, is a property of an object or system if it is distinguishable from its mirror image.
Chirality is found throughout nature. For instance, in chemistry, just like hands, crystals of tartaric acid found in wine can be left or right-handed, which leads to them transmitting light differently. Similarly, in biology, amino acids that make up proteins exist in left- and right-handed forms, but, curiously, natural proteins almost exclusively contain the left-handed type.
Chirality shows up in light when the lightwave, called the electromagnetic field, twists as it travels. It can twist right or left, leading to right or left circularly polarized light, and chiral materials interact differently with each type.
Chirality shows up in magnets when the tiny magnetic “arrows” called spins inside the material line up in a right- or left-twisting pattern, like a spiral or little whirlpool. This handed pattern can change how the magnet behaves and how currents move through it.
The concept of chirality can also be more abstract, like in particle physics. Here it isn’t a visible twist in space, but a built-in left–right label in the mathematical equations that describe particles called fermions. The theory splits each fermion’s field into a left-handed part and a right-handed part. This matters because the weak interaction, one of nature’s four fundamental forces, prefers the left-handed part. That preference has implications for radioactive decay and scientists are actively studying whether this may connect to bigger questions like why the universe contains more matter than antimatter.
What is Meta Matter?
The term “Meta Matter,” which we’ve coined, builds on the established concept of metamaterials.
Metamaterials are engineered materials with properties rarely found in nature. For example, when you stretch a piece of fabric, it usually narrows in the other direction, but one class of metamaterials, called auxetic materials, expands in all directions when stretched.
These unusual properties emerge from the structure of their building blocks rather than from the raw material itself. Such building blocks can range from the exceptionally tiny, like nanofabricated split-ring resonators that bend light in unconventional ways, to large, visible building block patterns such as origami folds and lattice designs.
At WPI-SKCM², we are interested in more than just materials, but matter, which is everything around us all the way to the smallest atoms and their smaller subatomic particles. Therefore, we’ve extended the term “metamaterial” to the more inclusive “Meta Matter” to encapsulate both materials and matter that are intentionally designed and engineered.
What is Knotted Chiral Meta Matter?
So what exactly is Knotted Chiral Meta Matter?
Let’s briefly review: Knot theory is the mathematical study that classifies knotted strings based on shape; Chirality is the property where a mirrored shape differs from the original; and Meta Matter refers to materials (and matter) that exhibit extraordinary properties due to specially engineered patterns. The common feature is that shape plays a crucial role in all three.
Therefore, Knotted Chiral Meta Matter is the emerging research field born from combining these three concepts to uncover new shapes, patterns, and phenomena across the natural world and the universe. Studying it is compelling in its own right, as knotted and chiral structures in nature offer a new lens for reinterpreting how matter fundamentally behaves.
However, while researching these fundamental questions in science, we have the opportunity to focus our efforts to design and develop materials with special properties to contribute to many global sustainability challenges.
What is it useful for?
At WPI-SKCM², researchers are tackling diverse projects aimed at creating Knotted Chiral Meta Matter solutions that can make real-world impact. A few impacts include designing drug therapies for protein-tangling diseases such as Alzheimer’s, creating porous molecules that can contribute to carbon capture, creating special interwoven gels, called aerogels, that can reduce building heating and cooling costs, and designing textiles that reduce waste from the fashion industry.
Please read about each project and their sustainability impacts here.