March 17, 2014

New State of Matter Discovered

by Zach Hartman


Credit: Baxley/JILA

One of the foundations of physics and chemistry is the concept of states of matter. While many have been discovered, in reality we only tend to pay attention to the big three: solids, liquids, and gases. Plasma is quite important to chemists and astronomers as well as it is the basis of reactions in stars. However, except for curiosity’s sake, we tend not to concern ourselves with the other states of matter like Bose-Einstein condensates and strange matter. They simply don’t have much application as of yet for our purposes.

Enter The Dropleton

A few weeks ago, the discovery of a new state of matter was reported in Nature. It has been dubbed the “dropleton,” owing to its similarities to a liquid. The dropleton is comprised of several excitons, which are formed when photons of light interact with particles of a semiconductor. When researchers were studying a gallium arsenide (GaAs) semiconductor, they expected that bombardment with photons would yield these excitons. What they did not expect was a composite of many excitons, leading to the discovery of a new state of matter. In quantum physics terms, the dropletons were massive and long-lived, stretching up to 200 nanometers and lasting up to 25 picoseconds. This makes them relatively easy to detect and test, giving scientists a new tool to understand how light can interact with matter.

Potential Application of Dropletons

All of this information makes for some fascinating science, but how will it exit the realm of curiosity? Why should chemists care about dropletons? These are, as yet, unanswered questions; however, there are many possibilities that come with the understanding of light and matter interaction. For starters, it may help physicists create a sort of artificial, giant electron that is easier to study and test. Theoretically, scientists can manipulate the amount of electrons that go into a dropleton, changing its properties.

It is also important that dropletons are created at the interface between light and matter. This opens up a new avenue of technology that has been a stalwart in physics and chemistry: light detection. The technology we have at our disposal for capturing light signals can be extremely fast. For example, photomultiplier tubes can turn a photon signal into an electrical current in approximately a nanosecond. Some of our best charge-coupled device-based cameras can capture an image in 200 picoseconds. The dropleton may be able to capture even faster interactions; however, since it is a brand new concept in physics, time will tell if some kind of “quantum camera” could be built.

It is also interesting to consider potential applications in spectroscopy. We know we can take advantage of matter interacting with light to help determine the identity of molecules. Now that we have a new method for studying light and matter interactions, might we be able to develop a new spectroscopic technique? Dropletons are interesting because they are rather flexible entities. They change as the structure around them changes, which could leave a signature of the material. As we build our understanding of dropletons further, it may be possible to expand the reach of spectroscopic techniques.


Dropletons are a new, interesting state of matter discovered by quantum physicists. They are large enough to be detected by conventional optics, and they last long enough to be studied. Time will tell what new applications and technology can be derived from this information, but even without direct application, this represents a new phenomenon that we can study to understand the basic properties of the universe.

Zach Hartman

Written by

Zach Hartman is a freelance medical writer specializing in educational writing. He received his PhD in biochemistry and molecular biology from West Virginia University in 2013, where he worked with the signaling protein SHP2 and its role in breast cancer. Now he covers a broad spectrum of topics.

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