New particle might make quantum condensation at room temperature possible

October 18, 2013, Fundamental Research on Matter (FOM)
Schematic representation of the system investigated. An array of silver nanorods is covered by a thin layer (grey) of silicon nitride to protect the silver from oxidising, and by a thicker layer of polymer and organic molecules (orange) that emit light. The light field from the nanorods (red tails) couples to the molecules (letters e and h enclosed by an ellipse), thereby forming plasmon-exciton-polaritons (PEPs). By increasing the density of PEPs, the researchers observed their effective cooling, which paves the way towards their quantum condensation. Credit: Fundamental Research on Matter (FOM)

Researchers from FOM Institute AMOLF, Philips Research, and the Autonomous University of Madrid have identified a new type of particle that might make quantum condensation possible at room temperature. The particles, so called PEPs, could be used for fundamental studies on quantum mechanics and applications in lasers and LEDs. The researchers published their results on 18 October in Physical Review Letters.

In quantum condensation (also known as Bose-Einstein condensation) microscopic with different energy levels collapse into a single macroscopic quantum state. In that state, particles can no longer be distinguished. They lose their individuality and so the matter can be considered to be one 'superparticle'.

Quantum condensation was predicted in the 1920s by Bose and Einstein, who theorised that particles will form a condensate at very low temperatures. The first experimental demonstration of the quantum condensate followed in the 1990s, when a gas of atoms was cooled to just a few billionths of a degree above absolute zero (-273°C). The need for such an extremely low temperature is related to the mass of the particles: the heavier the particles, the lower the temperature at which condensation occurs. This motivated an ongoing search for that may condense at higher temperatures than atoms. The eventual goal is to find particles that form a condensate at .


The researchers have created a particle that is a potential candidate for fulfilling the quest: the extremely light plasmon-exciton-polariton (PEP). This particle is hybrid between light and . It consists of photons (light particles), plasmons (particles composed of electrons oscillating in metallic nanoparticles) and excitons (charged particles in ).

The researchers made PEPs using an array of metallic nanoparticles coated with molecules that emit light. This system generates PEPs when it is loaded with energy. Through a careful design of the coupling between plasmons, excitons and photons, the researchers created PEPs with a mass a trillion times smaller than the mass of atoms.

Because of their small mass, these PEPs are suitable candidates for quantum condensation even at room temperature. However, due to losses in the system (such as absorption in the metal) PEPs have a short lifespan, which makes keeping them around long enough to condense a challenge.

First steps

The researchers have shown the first steps towards condensation of PEPs, demonstrating that PEPs cool down as their density increases. However, in the current system cooling down is limited by properties of the organic molecules used in the experiments, which lead to a saturation of the PEP density before sets in. The researchers envisage that it should be possible to overcome these challenges in the future.


To a large extent, PEPs are composed of photons. Therefore, their decay results in the emission of light. This emitted light has unique properties, which could constitute the basis of new optical devices. In view of recent advances from AMOLF and Philips Research towards improving white LEDs with similar systems, the researchers suggest that from a Bose-Einstein condensate might illuminate our living rooms in the future.

Explore further: Excitons: Exotic particles, chilled and trapped, form giant matter wave

Related Stories

Vienna physicists create quantum twin atoms

May 2, 2011

At the Vienna University of Technology, sophisticated atomchips have been used to create pairs of quantum mechanically connected atom-twins. Until now, similar experiments were only possible using photons.

Improving measurements by reducing quantum noise

June 27, 2013

If you want to measure something very precisely, such as slight variations of a length, then you are very likely to use light waves. However, many effects, such as variations of gravity, or surface forces, can only be measured ...

Speed limit on a superfluid helium nano-highway

October 9, 2013

Scientists from the University of Amsterdam (UvA), the Ecole Polytechnique Fédérale de Lausanne (EPFL) and the Universitat de Barcelona have been able to determine the so-called Landau velocity for helium nanodroplets down ...

Quantum particles find safety in numbers

October 16, 2013

Ludwig Maximilian University of Munich researchers have uncovered a novel effect that, in principle, offers a means of stabilizing quantum systems against decoherence. The discovery could represent a major step forward for ...

Recommended for you

Researchers make shape shifting cell breakthrough

December 11, 2018

A new computational model developed by researchers from The City College of New York and Yale gives a clearer picture of the structure and mechanics of soft, shape-changing cells that could provide a better understanding ...

Novel laser technology for microchip-size chemical sensors

December 11, 2018

Most lasers emit photons of exactly the same wavelength, producing a single color. However, there are also lasers that consist of many frequencies, with equal intervals in between, as in the teeth of a comb; thus, they are ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (2) Oct 18, 2013
nb: these aren't particles in the "fundamental" sense, like nothing is made of PEPs like they're made of quarks and electrons and stuff. The system of these materials arranged in this way has certain "excitations" that behave like other quantum particles.
1.4 / 5 (19) Oct 18, 2013
This is definate evidence that we are trading body parts with aliens for advanced technologies.
Bose Einstein condensates are zero entrophy systems. Zero entrophy is a prerequisite for ex-nihilo energy, as witness the conditions of the big bang.
(Big Bang only if we can believe the red shift= distance malarky. Proof by verbal repetition is not proof at all. Evidence is mounting that the Constants are not. There are many ways to get the foundations of our edifice wrong. Question everything.)
1 / 5 (2) Oct 18, 2013
This article has me shaking my head.

For one thing, PEPs are not new particles. They aren't even particles, but a particular type of short-lived interaction between particles and photons.

For another, it's not at all clear that you can form a Bose-Einstein condensate out of these interactions. The article treats it as an engineering problem, as if the theory behind the idea is settled. It isn't settled, as no-one has ever achieved a condensate made out of PEPs at *any* temperature, let alone room temperature.

And yet another: the article says, "Therefore, their decay results in the emission of light. This emitted light has unique properties, which could constitute the basis of new optical devices." Yet the article doesn't mention what those 'unique properties' are or what sort of new optical devices might arise from those properties.

I can't help but conclude that this is an unhelpful, hyperventilating, and credulous article.
1.8 / 5 (5) Oct 19, 2013
yet the article doesn't mention
I can't fathom why someone would think they can draw conclusions such as yours from reading a press release of what must be a very detailed paper about a very involved series of experiments based on very complex science. Why don't you do some research first to try and find the original paper?
1.4 / 5 (10) Oct 20, 2013
This is definate evidence [...]


Never question grammar.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.