Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Quantum 'kisses 'change the color of space

Published in Nature, observed for the first time with optical methods the quantum regime in the interaction between nano-sized spheres of gold

Researchers from the Donostia International Physics Center (DIPC) and the Materials Physics Center in Donostia-San Sebastián (CFM) have observed for the first time, with optical methods, the quantum regime in the interaction between nano-sized spheres of gold.

The image shows, in an artistic manner, the change in color when a quantum tunnel effect is produced in a subnanometric gap.

Credit: Picture courtesy of Cambridge University

This quantum regime has been identified thanks to the change of colour of the gap or empty space between these particles when these are at distances of less than one nanometre. This work, published in Nature journal, enables literally "seeing" a quantum kiss between nanoparticles.

The gap generated between two opposing nanospheres of gold can change its colour when the distance between them is less than one nanometre, according to recent research co-directed by researchers from the DIPC and the CFM (a joint center between the CSIC [Spanish Scientific Research Council] and the UPV/EHU [the University of the Basque Country]), both based in the Basque City of Donostia-San Sebastián, and in collaboration with researchers from the Universities of Cambridge and Paris-Sud.

This work published in Nature, confirmed that electrons accumulated on the gold walls around the illuminated gap between the spheres can "jump" from one to the other, thanks to the tunnel effect, thus reducing the accumulated charge on the surface of each of these spheres and modify the colour of the gap from red to blue (blueshifting).

This work enables literally "seeing" the effects of quantum mechanics and shows how light interacts with matter at subnanometre sizes. The change in colour of the gap is a "chromatic fingerprint" that identifies the initiation of a quantum regime therein - an effect that had been predicted by the theoretical team of Dr. Aizpurua, the lead researcher in Donostia, and now fully identified as a result of this research. To this end, highly sophisticated experiments have been combined with very advanced theories.

When two metallic spheres with a sufficiently small separation between them are illuminated with white light, this gap acquires colour thanks to the interaction of the electrons on the surface of the spheres with light. The beam of light 'pushes' the electrons and makes them oscillate, which gives a red colour to the gap. As the spheres get closer, the electron charge increases and this red colour intensifies. When the distance between both is reduced to under 0.35 nanometres, this accumulation of charge can be seen to drop, due to the tunnel effect, and thanks to which the electrons can jump from one ball to another without the spheres coming into contact with each other. Just as the quantum theory developed by the research teams in Donostia and Paris predicted, it is possible to identify this quantum electronic leap, given that, as the accumulated charge drops, the red colour of the gap changes to blue.

Experimental team leader and University of Cambridge researcher, Professor Jeremy Baumberg compares this reduction in charge with the tension released from a kiss "we think of this like the tension building up between a romantic couple. As their faces get closer the tension mounts, and only a kiss discharges this energy". In this case, however, the gold nanospheres approaching each other generate a virtual kiss, as they never actually touch, releasing the charge on their surfaces and changing the colour of the gap between them. As Professor Baumberg says, "it is practically like kissing, without the lips actually touching".

The experimental team at Cambridge explained: "aligning two gold nano-particles is like closing your eyes and trying to hold two needles with the fingers of either hand so that the points of each needle touch. Achieving this has meant years of hard work".

Javier Aizpurua commented that, in order to predict the colour changes now confirmed with this experiment, "the fusion of the quantum vision with the classical vision of the world" was necessary. "The modelling of so many electrons oscillating within the gold particles in response to a beam of light could not be described with existing theories", assured the CSIC and DIPC researcher.

This new result establishes a fundamental quantum limit for the minimum dimensions within which we can trap light. Moreover, this reinterpretation of the interaction between light and matter at a sub-nanometric scale could provide new ways of describing and measuring the atomic-scale world and open doors to new strategies for the manufacture of even smaller optoelectric technological devices and access new limits of resolution in photochemistry.

This research was funded by the Basque Government through its Science Agency, Ikerbasque, and the ETORTEK Nanoscience and Nanotechnology project, as well as by a European Union initiative through the Eranet CUBiHOLE project which originally brought together the teams involved in this research. Part of this work was developed during the time spent by Professor Baumberg as an Ikerbasque Visiting Professor at the DIPC.

Aitziber Lasa | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Weizmann physicists image electrons flowing like water
11.12.2019 | Weizmann Institute of Science

nachricht Revealing the physics of the Sun with Parker Solar Probe
11.12.2019 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Highly charged ion paves the way towards new physics

In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.

Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...

Im Focus: Ultrafast stimulated emission microscopy of single nanocrystals in Science

The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.

Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...

Im Focus: How to induce magnetism in graphene

Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.

Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...

Im Focus: Electronic map reveals 'rules of the road' in superconductor

Band structure map exposes iron selenide's enigmatic electronic signature

Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

Latest News

Self-driving microrobots

11.12.2019 | Materials Sciences

Innovation boost for “learning factory”: European research project “SemI40” generates path-breaking findings

11.12.2019 | Information Technology

Molecular milk mayonnaise: How mouthfeel and microscopic properties are related in mayonnaise

11.12.2019 | Life Sciences

Science & Research
Overview of more VideoLinks >>>