8 Things You Need to Know about Dropleton or Quantum Droplet

By Maschen (Own work) [CC0], via Wikimedia Commons

By Maschen (Own work) [CC0], via Wikimedia Commons

Physicists in the United States and Germany reported their discovery of an exotic new type of particle. This new development in the field of quantum physics was published on the journal Nature on February 26, Wednesday. The new particle is called dropleton or a quantum droplet, observed to possess properties that are useful in the study of quantum mechanics.

Interested to learn more about this very recent discovery? The following are the details you should know:

1. The Discoverers

Dropleton was discovered by researchers from multiple institutions. The experiments were conducted by the JILA (formerly called the Joint Institute for Laboratory Astrophysics) and University of Colorado team while the theory was furnished predominantly by researchers from the Philipps-University Marburg.

The researchers involved in this discovery are A.E. Almand-Hunter and S. T. Cundiff of the University of Colorado Boulder Department of Physics; M. Mootz, M. Kira and S. W. Koch of the Philipps-University Marburg; and H. Li from JILA.

2. It Is a Quasiparticle

Dropleton is described as a quasiparticle that features the attributes of being part particle and part liquid. A quasiparticle is a grouping of smaller types of particles that happens when a microscopically complicated system exhibits the characteristic of seemingly containing particles in free space that move around weakly.

Basically, dropleton is an assemblage of electrons and “holes” within a semiconductor. These “holes” are parts where electrons are nonexistent. Dropleton is considered a quasiparticle because of its non-elementary nature. Unlike the quarks and electrons that comprise atoms, dropleton is composite. M. Kira, one of the discoverers, says that dropleton is “a particle inside matter, and it is an entity whose properties are determined by its environment.”

Dropleton is the first quasiparticle observed to exhibit the behavior of a liquid. Also, it can only exist inside solid materials.

3. How the Dropleton Was Discovered

The researchers did not expect or anticipate the creation of the dropleton. It only emerged when energy pulses were projected from a superfast laser at a gallium arsenide semiconductor. The pulses produced excitons or pairs of “holes” in the gallium arsenide semiconductor. These excitons eventually disappeared upon reaching a certain level, leaving “holes” alongside the electrons.

The electrons and “holes” then arranged in new formations. Interestingly, the “holes” moved around like particles suspended but moving around inside a droplet. M. Kira says that “it’s like a quantum form of a typical liquid.”

By YAGO rus (Own work) [GFDL (, CC-BY-SA-3.0 ( or FAL], via Wikimedia Commons

By YAGO rus (Own work) [GFDL (, CC-BY-SA-3.0 ( or FAL], via Wikimedia Commons

4. How Dropleton Got Its Name

The name dropleton comes from the water droplet analogy mentioned above. The researchers, upon observing the phenomenon, realized that what they were seeing should be a new particle given its small size and liquid properties.

5. Relatively Long-Lived

Dropletons can exist for only around 25 picoseconds. That means 25 one trillionths of a second. It certainly isn’t what a layman would call long-lived but in comparison to other quasiparticles, it is. Additionally, dropletons are stable enough to allow scientists to undertake experiments on them.

The combination of longevity and stability allows dropletons to help scientists in undertaking new investigations into quantum interactions of light and matter. Their discovery will certainly boost developments in the field of quantum physics.

6. Dropleton Dimensions

A dropleton is around 200 nanometers (1 nanonmeter = 1 billionth of a meter) in width. This makes it around 10 times bigger than single exciton pairs and about as large as the smallest bacteria known to man.

7. Dropletons Have Not Been Actually Seen Yet

There is no microscopic image of a dropleton yet. As M. Kira says, “It would be really neat to not only detect spectroscopic information about the dropleton, but to really see the dropleton.” Yes, they have only observed the manifestations of the existence of a dropleton but they haven’t actually seen it with their own eyes.

This is because “classical optics can detect only objects that are larger than their wavelengths,” M. Kira mentions. The laser light used to excite the semiconductor in which the dropleton was discovered has a wavelength of 800 nanometers. It is four times the width of the dropleton. Hence, dropletons couldn’t be properly visualized yet. The researchers could not produce an actual image of dropletons yet.

8. Practical Applications

According to S. Cundiff of JILA, “Even though this happens so rapidly, it is still useful to understand that it does happen.” The knowledge of dropleton and further studies on it will have future benefits.

M. Kira adds that “the effects that give rise to the formation of dropletons also influence the electrons in optoelectronic devices such as laser diodes.” Studies on the properties and possible effects of dropletons can help in the development of lasers or laser systems with the capability of encoding quantum information.

Public Domain / Benjah-bmm27

Public Domain / Benjah-bmm27

The dropleton discovery may not really mean anything much to those who are more interested in more perceivable technologies like artificial muscles or 3D printing. However, it is an important development in quantum physics that is bound to manifest its benefits in the not so distant future.