New State of Matter Discovered in a Rock

Herbsmithite Ore

In 1972, a mineral was found in Chile that scientists now believe is an example of a new state of matter that had not yet been naturally observed in our Universe (by us, that is), and had not even been theorized about for at least a decade after the Chilean find. The mineral goes by the rather nerdy name of Herbertsmithite, or the even nerdier name of Tricopper zinc hexahydroxyl dichloride (ZnCu₃(OH)₆Cl₂). Herbertsmithite is a string-net liquid with elementary and quasi-particles at the end of each string in the form of a Fractional Quantum Hall. Shall I explain?

Some background: It has generally been accepted that there are three basic states of all matter in our Universe: solid, liquid, and gas. Recently, plasma has been considered a fourth state of matter. Most matter can be changed from one state to another, and doing so often changes the properties of that matter. For instance, the natural state of water at room temperature (a room located on Earth) is liquid. It can be turned into a solid (ice) through freezing, and back to a liquid through melting. It can also be turned into a gas (steam) through vaporization, and back to a liquid through condensation. Even a solid can be converted directly to a gas through sublimation, and back again to a solid through deposition. Plasma can be converted back and force into a gas via ionization and deionization, but let's not get into that now.

In 1998, the Nobel Prize for Physics was awarded to three scientists for the devising and explaining the Fractional Quantum Hall Effect (FQHE), which theorizes a new state of matter called String-Net Liquid (SNL). This theory actually impacts on our understanding of how the entire Universe space-time continuum works. FQHE and SNL are related to the concepts I explained in the previous blog entry "Spooky Action at a Distance: Communication Faster Than the Speed of Light," which deals with "entanglement," the term that describes how certain sub-atomic particles are instantly affected by others across vast distances. Since readers did not ask any questions, I can only assume that the concepts were well understood and remembered, so I won't repeat them here.

String-Net Liquid

To explain FQHE/SNL theory in detail would take a lot more blog space than we have here, so I'll try to simplify things, and you can ask your physicist friends to answer your remaining nagging concerns. Basically, the theory is that all of space-time consists of "strings" (think of noodles), and what we observe (atomic particles) are the tips. What we assume is "empty" space is actually filled with the rest of the string organized in a kind of "net." There is only one type of structure that could explain all of this, a Kagome Lattice.

Kagome Lattice

Kagome Lattice

A Kagome Lattice is an arrangement of lines composed of interlaced triangles such that each point where two lines cross has four neighboring points. There are two triangles and two hexagons alternating on each vertex (see image). How does this arrangement explain SNL? Electrons spin in specific directions, and they prefer to neighbor electrons that spin in the opposite direction. This is not possible in a triangular arrangement, which is the basis of the Kagome Lattice -- if there are electrons at each triangle's point, there will always be two electrons with the same spin direction. These spin contractions cause matter to enter a random fluctuating state known as a spin liquid. This state is unlike any of the three (or four) accepted states of matter.

Herbertsmithite

So, what does some Chilean rock have to to with our understanding of the nature of our Universe? First, let's get some definitions:

Rock -- A rock is an aggregate of minerals and does not have a specific chemical composition. Herbertsmithite could be one of a few minerals physically (but not atomically) shmooshed together as a rock.

Mineral -- A mineral is a naturally occurring solid chemical substance that has a specific chemical composition, highly ordered atomic structure in crystalline form, and specific physical properties. A mineral can consist of just one atomic element -- i.e., Gold (Au), Silver (Ag), Copper (Cu) -- but generally is composed of a few elements that are atomically bound together, such as Salt (NaCl), a combination of Sodium (Na) and Chlorine (Cl); or Quartz (SiO4), a combination of Silicon (Si) and Oxygen (O). There are as many as 6,500 known minerals throughout the world, and every year new ones are being named. Herbertsmithite is a mineral consisting of varying amounts of the elements Zinc, Copper, Oxygen, Hydrogen, and Chlorine.

Ok, now to answer the question: What does some Chilean rock have to to with our understanding of the nature of our Universe? First, you now know that Herbertsmithite is not just a rock; it is a mineral. Second, its crystalline form is arranged in a Kagome Lattice. This arrangement gives it properties not found in any other substance on Earth.

If it were "ordinary" matter, the spin of its electrons should cease fluctuating and point to specific directions (a condition known as "magnetic order") when cooled to under 27C (81F). However, this does not happen with Herbertsmithite, even when cooled to nearly Absolute Zero. Also, in "ordinary" solids, the relationship between their temperature and the ability to store heat is altered below a certain temperature -- the structure of the solid changes. However, this does not happen with Herbertsmithite. Its lowest energy state has no discernible order. Its structure does not change. In other words, Herbertsmithite can never be "frozen" -- its molecules continue to move even at Absolute Zero, without the input of any energy.

Scientists are next going to study Herbsmithite's natural ability to entangle its electrons (see above about entanglement). This will have far-reaching effects in quantum computing, which will be the next great leap in data acquisition, storage, and analysis.

So, you have learned today that the Universe is actually large bowl of soup consisting of a net made out of noodles. And we found out about all this by looking at a rock. 

Herbsmithite Crystals