總瀏覽量

2016年8月7日 星期日

Scientists discover New Property of Photon (科學家發現新的光子特性)



Religious truths are said to be eternal. Throughout the ages, theologians and priests have repeatedly told their faithfuls what they claim to be "truths" about what this world of ours is like and when they have the needed political power, would show little restraint in using it to enforce the correctness of their views. The story of the fate of Copernicus and Galileo is now history.

What should be the proper relation between religion and science? Is the finding of science always in conflict with the dogmatic "truths" of religion? Or just sometimes eg. as when theologians eagerly adopted the "Big Bang" theory of the creation of the universe?


Whatever the truth may be, natural scientists have long abandoned revelation, faith and mysticism as sources of truth and seek their "truths" directly by interrogating physical nature itself through empirical observation, probing experimental predictions based on educated hypotheses which are later either confirmed or refuted by further observation and when they have accumulated a sufficient number of such observations, build theories to link up such isolated observations with the help of the precise mathematical formulas. Different from the unalterable dogmatic "truths" of religion, scientific "truths" are always tentative and open to further revision in the light of newer observations and better and more comprehensive theories.  That's why for me, the scientific outlook serves as a much better and more reliable guide on what the "truths" about this world and about what we ourselves may be like than the "truths" of religion. That's also why scientists are frequently able to shed new light upon what this world of ours is like and from time to time, astound us with truly surprising new discoveries about our world.

One such new discovery is on the property of light about which we thought we already know quite a lot eg. that light travels in a straight line (until Einstein came along with his special theory of relativity), that its speed in a vacuum is 299,792,458 metres per second (approximately 3.00×108 m/s or about 300,000 meters per second), that nothing in the universe can travel faster than the speed of light,  that the photon has zero mass, zero electrical charge and a spin of 1  etc. Well, well, well, now scientists have discovered yet another new property of light!  What is that?


Scientists discover light could exist in a previously unknown form

Date: August 5, 2016

Source: Imperial College London

Summary:

New research suggests that it is possible to create a new form of light by binding light to a single electron, combining the properties of both.



According to the scientists behind the study, from Imperial College London, the coupled light and electron would have properties that could lead to circuits that work with packages of light -- photons -- instead of electrons.

It would also allow researchers to study quantum physical phenomena, which govern particles smaller than atoms, on a visible scale.

In normal materials, light interacts with a whole host of electrons present on the surface and within the material. But by using theoretical physics to model the behaviour of light and a recently-discovered class of materials known as topological insulators, Imperial researchers have found that it could interact with just one electron on the surface.

This would create a coupling that merges some of the properties of the light and the electron. Normally, light travels in a straight line, but when bound to the electron it would instead follow its path, tracing the surface of the material.

In the study, published today in Nature Communications, Dr Vincenzo Giannini and colleagues modelled this interaction around a nanoparticle -- a small sphere below 0.00000001 metres in diameter -- made of a topological insulator.

Their models showed that as well as the light taking the property of the electron and circulating the particle, the electron would also take on some of the properties of the light.

Normally, as electrons are travelling along materials, such as electrical circuits, they will stop when faced with a defect. However, Dr Giannini's team discovered that even if there were imperfections in the surface of the nanoparticle, the electron would still be able to travel onwards with the aid of the light.

If this could be adapted into photonic circuits, they would be more robust and less vulnerable to disruption and physical imperfections.

Dr Giannini said: "The results of this research will have a huge impact on the way we conceive light. Topological insulators were only discovered in the last decade, but are already providing us with new phenomena to study and new ways to explore important concepts in physics."

Dr Giannini added that it should be possible to observe the phenomena he has modelled in experiments using current technology, and the team is working with experimental physicists to make this a reality.

He believes that the process that leads to the creation of this new form of light could be scaled up so that the phenomena could observed much more easily. Currently, quantum phenomena can only be seen when looking at very small objects or objects that have been super-cooled, but this could allow scientists to study these kinds of behaviour at room temperature. 

Story Source:

The above post is reprinted from materials provided by Imperial College London. Note: Content may be edited for style and length. 

Journal Reference
:

1.       G. Siroki, D.K.K. Lee, P. D. Haynes, V. Giannini. Single-electron induced surface plasmons on a topological nanoparticle. Nature Communications, 2016; 7: 12375 DOI: 10.1038/NCOMMS12375


Imperial College London. "Scientists discover light could exist in a previously unknown form." ScienceDaily. ScienceDaily, 5 August 2016. <www.sciencedaily.com/releases/2016/08/160805092214.htm>