A stream of superfluid light

June 5, 2017
The flow of polaritons encounters an obstacle in the supersonic (top) and superfluid (bottom) regime. Credit: Polytechnique Montreal

Scientists have known for centuries that light is composed of waves. The fact that light can also behave as a liquid, rippling and spiraling around obstacles like the current of a river, is a much more recent finding that is still a subject of active research. The "liquid" properties of light emerge under special circumstances, when the photons that form the light wave are able to interact with each other.

Researchers from CNR NANOTEC of Lecce in Italy, in collaboration with Polytechnique Montreal in Canada have shown that for light "dressed" with electrons, an even more dramatic effect occurs. Light become superfluid, showing frictionless flow when flowing across an obstacle and reconnecting behind it without any ripples.

Daniele Sanvitto, leading the experimental research group that observed this phenomenon, states that "Superfluidity is an impressive effect, normally observed only at temperatures close to absolute zero (-273 degrees Celsius), such as in liquid Helium and ultracold atomic gasses. The extraordinary observation in our work is that we have demonstrated that superfluidity can also occur at room-temperature, under ambient conditions, using light-matter particles called polaritons."

"Superfluidity, which allows a fluid in the absence of viscosity to literally leak out of its container", adds Sanvitto, "is linked to the ability of all the particles to condense in a state called a Bose-Einstein condensate, also known as the fifth state of matter, in which particles behave like a single macroscopic wave, oscillating all at the same frequency.

Scientists have known for centuries that light is composed of waves. The fact that light can also behave as a liquid, rippling and spiraling around obstacles like the current of a river, is a much more recent finding that is still a subject of active research. The 'liquid' properties of light emerge under special circumstances, when the photons that form the light wave are able to interact with each other. Credit: Polytechnique Montreal

Something similar happens, for example, in superconductors: electrons, in pairs, condense, giving rise to superfluids or super-currents able to conduct electricity without losses."

These experiments have shown that it is possible to obtain superfluidity at room-temperature, whereas until now this property was achievable only at temperatures close to absolute zero. This could allow for its use in future photonic devices.

Stéphane Kéna-Cohen, the coordinator of the Montreal team, states: "To achieve at room temperature, we sandwiched an ultrathin film of organic molecules between two highly reflective mirrors. Light interacts very strongly with the molecules as it bounces back and forth between the mirrors and this allowed us to form the hybrid light-matter fluid. In this way, we can combine the properties of photons such as their effective mass and fast velocity, with strong interactions due to the electrons within the molecules. Under normal conditions, a fluid ripples and whirls around anything that interferes with its flow. In a superfluid, this turbulence is suppressed around obstacles, causing the flow to continue on its way unaltered".

"The fact that such an effect is observed under ", says the research team, "can spark an enormous amount of future work, not only to study fundamental phenomena related to Bose-Einstein condensates with table-top experiments, but also to conceive and design future photonic superfluid-based devices where losses are completely suppressed and new unexpected phenomena can be exploited".

The study is published in Nature Physics.

Explore further: Team demonstrates wavelike quantum behaviour of polariton condensate on macroscopic scale and at room temperature

More information: Room-temperature superfluidity in a polariton condensate, Nature Physics, nature.com/articles/doi:10.1038/nphys4147

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Hyperfuzzy
1 / 5 (3) Jun 05, 2017
Not sure this makes any sense. Light, i.e. visible light are simply sourced by a set of charge centers; then, what may you see? Depends, using transforms; however the source, so, what?
Hyperfuzzy
2 / 5 (2) Jun 05, 2017
Superfluidity? Did you mean laminar and directional, and ... i,e, on what level of granularity. Or is this just a collective shimer?
Da Schneib
3 / 5 (4) Jun 05, 2017
Very interesting. Lots of technical applications here.

One easy example: bypassing defects in crystalline matrices of various sorts, making whatever device this is part of tolerant of defects, and reducing the effort to make the device usable, thus reducing costs.
shavera
4 / 5 (4) Jun 05, 2017
Hyper: not necessarily light in the sense of free photons travelling from a single charged particle to another. They're referring to electromagnetic fields in media, where the EM fields are coupled to charged particles to form 'effective' fields. The photons in this effective field are behaving like a superfluid similarly to how very cold helium atoms behave like a superfluid.
Dingbone
3 / 5 (2) Jun 05, 2017
The article title is intentionally misleading as it attracts just the rationally thinking people who get perplexed with apparent controversy. The light applies only to visible EM radiation free of any coupling with material. The surface plasmons are definitely not light, but merely vibrations of material induced with EM field. They also propagate way slower and at small distances only. Other than that, this study (or rather presentation of it) is not new.
swordsman
3 / 5 (2) Jun 05, 2017
Another example of the lack of knowledge about electromagnetic radiation. Max Planck analyzed it and used his knowledge to formulate his original quantum theory. The main question at that time was the modeling of electromagnetic radiation waves. Electronic engineers developed a set of three equations based on actual radiation from an antenna. The first model was presented in 1936, and it showed that there is a time/phase difference that occurs of the axis of the antenna. This illustrates the fact that radiation is not spherical, in deference to the main assumption of the Einstein QM theory. Photons are not particles, and there is a great deal of proof thereof. The problems is that QM and the original Planck electron model have differences, and QM does not conform to all measurements, whereas the electronic model does conform. The adoption of the QM model has led to all of these difficulties and misunderstandings, whereas there are no such problems for the electronic model of Planck.
Hyperfuzzy
not rated yet Jun 06, 2017
Hyper: not necessarily light in the sense of free photons travelling from a single charged particle to another. They're referring to electromagnetic fields in media, where the EM fields are coupled to charged particles to form 'effective' fields. The photons in this effective field are behaving like a superfluid similarly to how very cold helium atoms behave like a superfluid.

same question
Hyperfuzzy
not rated yet Jun 06, 2017
... no such problems for the electronic model of Planck


please QM is is only a wave equation, not a theory, we try to define reality by a potential and a kinetic energy. The photons, particles etc. are field events, maybe. juz say'n
Hyperfuzzy
5 / 5 (1) Jun 06, 2017
in other words, when i look at the sea, why do i see waves, when i look at this why do i see something like liquid flow. trying to explain the light as causal is like saying the rock is hard cause it's a rock

it's as bad as assigning mass to bipolar elements of a mass, or agreeing with Einstein because you didn't think about measuring the wavelet, mi.e original wavelength by the measured period.

Or that a neutron is a neutral fundamental particle and not a contained proton and electron.

Or that you assume the proton and the electron as different particles entirely and not just opposite spherical fields, never created or destroyed.

Or that the field shape is due to the transmitter and the media, so no need to deny Coulomb.

Or that democracy works among Money Grubbers, in order for democracy to work. we must rid ourselves of money, it's worthless anyway, as well as modern physics, worthless.
Macksb
not rated yet Jul 11, 2017
The above article confirms posts that I made years ago in two Physorg articles. One such article dealt with superfluid light, and the other dealt with polaritons and their collective action:

"Physicists show that superfluid light is possible," October 27, 2010.

"Seeing quantum mechanics with the naked eye," January 9, 2012 (collective polaritons)

As noted in the above article, this "ambient temperature superfluid light" was achieved with the use of polaritons:

"...we have demonstrated that superfluidity can also occur, at room-temperature, under ambient conditions, using light-matter particles called polaritons." See third paragraph in above article.

My posts years ago in the 2010 (superfluid light) and 2012 (collective polaritons) articles explain both phenomena--superfluid light and collective action of polaritons. In both cases, I cited Art Winfree and his "law" of coupled periodic oscillators, proposing that it applied usefully to physics.

Macksb
not rated yet Jul 11, 2017
In the same vein, see "Scientists get first direct look at how electrons 'dance' with vibrating atoms," July 6, 2017 That Physorg article deals with superconductivity.

The result described in that article validates many posts I have made since 2010 about Art Winfree's law of coupled periodic oscillators as it applies to, and elucidates, superconductivity of all types, old and new.

The "dance" described in the title of that article is the coupling between one set of periodic oscillations (electrons) and another set of periodic oscillations (atomic vibrations. As the article says, they "move in sync .. as if they were dancing to the same beat."

Hyperfuzzy
not rated yet Jul 11, 2017
OK, so we look at the ocean's waves and forget the body of the ocean, the planet, the moon, the sun, the galaxy, the universe, as a separable equation using random wavelets, and strange interpretations with no basis. We also seek legitimacy by other writers; while all along, no one has it right and never has. Except, Maxwell tabulated empiricism. We add nonsense.

By the way, it is what it is; Maxwell tabulated it. Our foolishness is problematic. juz say'n

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