Nobel 2023 Part II

October 4, 2023
What an interesting year this has been for the Nobel Prizes! 

As most of you know, I don't usually write about the Nobel Prize in Chemistry, because I am not a chemist by training. I have always been interested in chemistry, but my training and research is entirely in theoretical physics and mathematics. However this year is a bit of an exception for one simple reason - the Nobel Prize in Chemistry has been awarded for work that is closely related to quantum physics, which was always one of the subjects that I was interested in as a research physicist. (It is also interesting to me that this year the Nobel Prize for Chemistry is for work in quantum physics, while the Nobel Prize in Physics was for work whose practical applications are more focused on chemistry. Perhaps someone mixed up the envelopes :) )

This year the Nobel Prize in Chemistry has been awarded to Moungi Bawendi, Louis Brus and Alexei Ekimov for research into the creation and application of quantum dots. And while this might sound like something quite exotic and purely of academic interest, it is this work that has allowed for recent developments in coloured LEDs, flat screen televisions, and even medical imaging technologies that permit doctors to study blood vessels inside tumors.

The existence of quantum dots has been theorized almost since the development of modern quantum mechanics in the 1920s and 1930s, but their practical development in the laboratory and in industry are relatively recent achievements. And the three winners of the Nobel Prize were each independently responsible for parts of these advancements over the last forty years.

The earliest of these was Ekimov's work through the early 1980s, which the discovery that colour of glass actually varies depending on the size and quantity of clusters of copper chloride molecules contained in it, and the determination that it was inherently an effect of quantum mechanics. Then a few years later, Brus made similar ground-breaking discoveries while studying the colour of fluids. And the final recipient, Bawendi, then made a more technical breakthrough in 1993 by developing methods of using clusters of molecules, each containing between a few hundred and a few thousand atoms, to produce quantum dots reliably and on a larger and economical scale.

A full explanation of the science of quantum dots is beyond the scope of this article, but it can be summarized as follows:

When there is a cluster of atoms, the electrons contained within their orbitals can move between them. However the electrons cannot leave the cluster, and are constrained to certain orbits throughout the cluster. According to the laws of quantum mechanics, electrons in each of these orbits will have very specific energies which are unique to the size and composition of the cluster. And as anyone who has taken an introductory quantum physics course knows (or who even has watched a Youtube video on the subject), when electrons change energy levels (or switch orbits) they either absorb or emit light at very specific frequencies.

If the cluster is very large - such as millions of billions of atoms wide - then there are so many possible orbits and energy level transitions that all of the frequencies run together and we see a continuous range of colours. But in the case of nanoscale clusters, containing just a few thousand atoms at most, the energy transitions are more restricted. For these smaller clusters, light will be emitted in only specific frequencies, and thus the clusters will always absorb and emit light in a few (or even just one) characteristic colours.

By manufacturing such quantum dots of a specific size and composition, we can create solids and fluids that will glow with virtually any colour we wish to manufacture. If we use these quantum dots in semiconductor crystals, then we can create light emitting diodes that glow in a specific colour. This same method can be used to create display screens by combining different types of quantum dots to display all of the colours visible to the human eye. And being of nanoscale size, and usually inert, the quantum dots can even be injected into the human body to conduct medical studies and treatments by either causing them to glow, or by causing them to selectively absorb electromagnetic radiation that the surrounding tissues do not.

In truth, both the research uses and practical applications of quantum dots are endless, and are still the subject of research by thousands of groups around the world. We are just now beginning to enter the age of nanotechnology, and quantum dots are one of the technologies at the forefront of this growing field.

Congratulations to all of the people involved in this research, and especially to the three winners of the biggest prize in chemistry. It is indeed a very important achievement, and definitely worth of the 2023 Nobel Prize in Chemistry.
 

Nobel 2023

October 3, 2023
The winners of the 2023 Nobel Prize in Physics have just been announced, and once again it is a fascinating area of research that I think most people would not have thought about as a potential candidate for the top prize in science, but which is very worthy of this recognition and reward.

This year's award was given to to French-Swedish physicist Anne L’Huillier, French scientist Pierre Agostini and Hungarian-born Ferenc Krausz for their extensive research on the dynamics of electrons, an...
Continue reading...
 

Antimatter Falls Down

September 28, 2023
Today it was announced that antimatter falls down.

That might sound trivial, but it is an interesting an important result in our understanding of particle physics and the laws of nature.

Everything that we see around us, and most of what we see in space, is formed of matter. However just over ninety years ago, physicists discovered that every known type of matter particle in nature is paired with another type of particle, known as antimatter. And whenever matter is created or destroyed, th...
Continue reading...
 

A Sign Of Life?

September 14, 2023
Sometimes it amazes me how quickly science advances.

Just over thirty years ago there were no known exoplanets, and some astrophysicists were even speculating on whether they ever would be detected. Then in the early 1990s, multiple teams of astronomers were able to detect the periodic dimming of distant stars, and later the Doppler shift in the light from other stars, and from that data they were able to conclusively prove the existence of exoplanets. Now there are several thousand known pla...
Continue reading...
 

Back to School

September 5, 2023

Some loyal readers will recognize this entry as a repeat from the last eight years. Each year it gets a good response, and kudos from my readers, and so as before I must appease my loyal followers...

To all the students starting University, enjoy this time of your life. Long ago when I started, a prof told me that this is the start of your real education. Now you get to choose your own courses and your own field of study. It is entirely up to you to decide what to do with this chance.

I know fr...


Continue reading...
 

Free Software

September 5, 2023
With the arrival of September, students around the world will be returning to classes this week (unless there is another pandemic outbreak). And for those who are starting out at college or university, one of the most important considerations is how to live on a budget. These are the years when one has little or no income, but must bear the expenses of living independently for the first time. While giving advice on living on a budget is far too expansive to cover in this blog, I can tackle on...
Continue reading...
 

More Muon Magnetism

August 18, 2023
Over the last few days, the scientific media has been reporting on a new result in quantum mechanics and particle physics, and promoting it as a major discovery or as the first signs of a fifth force of nature. The actual experimental result is the announcement of a more precise measurement of the magnetic moment of the muon, and further confirmation that it does not agree with the standard predictions of theoretical physics, but unfortunately it may not be as revolutionary as some articles a...
Continue reading...
 

Room Temperature Superconductors

August 10, 2023
There has been a lot of news coverage in recent weeks regarding the claimed discovery of a room temperature superconductor, and a lot of justified skepticism from the scientific community. In my own personal opinion, I believe that this latest claim will not withstand rigorous review and will be disproven, just based on some of the preliminary information from other research teams. However that is a different topic - today I will instead be reviewing exactly what a room temperature supercondu...
Continue reading...
 

Detecting The Gravitational Wave Background

June 29, 2023
There is another historic announcement from the astronomy community today, with the first detection of the gravitational wave background.

Our current best theory for explaining gravity is the general theory of relativity, created by Einstein (and arguably by Hilbert at the same time), in which what we perceive as the force of gravity is actually a warping of spacetime itself. One of the predictions of Einstein's theory is that when a system changes, such as a massive object moving or two obj...
Continue reading...
 

A Multitude of Multiverses

May 10, 2023
One of the unexpected benefits of the explosion of superhero movies and television programs is the popularization of the "Multiverse". This is a topic that has been discussed by theoretical physicists for decades (It was actually a key component of some of my own research a few years ago, and continues to be one of my interests for future research.), but in recent years it has also become a topic of discussion among the general public. In fact the inspiration for today's article was a chat I ...
Continue reading...
 

About Me


Dr. Chris Bird I am a theoretical physicist & mathematician, with training in electronics, programming, robotics, and a number of other related fields.

   


Make a free website with Yola