Monday, 22 January 2018
Tiny Neutrinos Could Hold the Answers to Universe’s Mysteries
Takaaki Kajita, Nobel Prize in Physics (2015)
In today’s opening plenary lecture, Professor Takaaki Kajita shared his knowledge on neutrinos and why the discovery that neutrinos have mass shook up the physics world - and earned him the 2015 Nobel Prize in Physics.
Before Professor Kajita’s discovery in 1998, the Standard Model of Physics assumed that neutrinos are massless. But within two years of Japan launching the Super-Kamiokande detector in 1996, “we were able to report the discovery of neutrino oscillations,” said Professor Kajita in this morning’s speech. The findings were ground-shaking, because the fact that neutrinos come in different flavours or types, and that they oscillate between these flavours implies they have mass.
It was a discovery so important that prompted the then US President Bill Clinton to make a bold declaration the day after, which Professor Kajita proudly quoted: “[The discovery] may change our most fundamental theories - from the nature of the smallest subatomic particles to how the universe itself works, and indeed how it expands.”
Why are neutrinos so important? That’s because understanding them can help explain why matter particles far outweigh antimatter particles, even though both sets were equal “in the Big Bang Universe,” says Professor Kajita. “I think neutrinos with very small masses might be the key to understanding the big mystery of the Universe.”
Black Holes - Does What Go in Have to Come Out?
Gerard ’t Hooft, Nobel Prize in Physics (1999)
“I’m a theoretical physicist,” declared Nobel laureate Professor Gerard ’t Hooft at the start of his talk. “My job is to focus on what happens when things get very very small...when you understand that, you should be able to integrate the equations and figure out how it works at the bigger scale.
”One of the biggest mysteries remaining in theoretical physics today is: how do we resolve quantum mechanics with the theory of relativity? To do that, we need to look where the gravitational field is the strongest, says Professor ’t Hooft. “And that’s in the tiniest black holes.”
Black holes have captured the fascination of physicists for decades. In 2015, Stephen Hawking discovered that “black holes aren’t as black” and that “they behave like other forms of matter - things go in and things come out,” explained Professor ’t Hooft. But how and why they do so, and its properties, remains a source of debate, with suggested theories including holography.
A big change in the concept of black holes is learning that “particles going out are positioned entirely by the things that went in,” he says. “Imagine a land full of snow...you don’t see the terrible snowman itself, you just see its footprint. Its footprints are the terrible snowman. All the particles are coming out in the form of footprints, if you replace the footprints with particles, you get some remarkable results.”
An Information Revolution driven by AI and Deep Learning
John Hopcroft, Turing Award (1986)
In his plenary lecture, Turing Award winner Professor John Hopcroft introduced the audience to deep learning. “We are going through an Information Revolution, and the consequences of this revolution will be as great as the Industrial or Agricultural Revolution,” said Professor Hopcroft. “One of the drivers of this is AI, and deep learning is an important part of that.”
Interest in deep learning really took off after Alexnet succeeded in reducing the error rate of image classification by nearly half - from 25 to 15 percent - during the 2012 Image Net competition. “This was so major an advance that companies all over the world started using this technology, which they called deep learning, in many different areas - finance, sociology and medicine - and it worked tremendously well,” Professor Hopcroft said. Today, technology has advanced to the point where it’s better than humans at identifying images (with an error rate of less than 5 percent).
“It is what’s going to drive your car in the future,” he declared. But computer scientists are still tackling various issues such as improving unsupervised learning (“we don’t want to have to train [your self-driving vehicle] with every possible situation it could encounter; we would like as it drives you around, to learn better and better”), learning to complete two different tasks separately (“you want to know what is common to these two tasks, such as learning Mandarin and English”) and avoiding AI systems from being fooled, among others.
Yet it’s important to recognise that AI, in its current state, isn’t real, says Professor Hopcroft. “It’s pattern recognition in high-dimensional space. But AI programmes do not extract the essence of an object or understand its function and other important aspects.” Give it another 40 years, and the Information Revolution may be complete, he says.
Physics Helps us Understand our Universe and the Current State of our World
François Englert, Nobel Prize in Physics (2013)
In the fourth and final plenary lecture of the day, Professor François Englert traced the development of physics thought throughout the centuries. From the time of Galileo to Newton, Maxwell and Einstein, the field of physics has evolved to study particles as waves to exploring the origin of dark matter in the Universe.
“The scientific understanding of the world which I have sketched here is the thought of fundamental research in physics...it’s one of the ways we have to understand the Universe,” Professor Englert said. Because of physics, we can now trace the history of the Universe itself up to less than a billionth of a second after the Big Bang. “And that has not only brought something to the understanding of the earth, but it has shaped the whole society.”
The study of physics, he says, is a rational approach to knowledge that serves more than just the scientifically curious, but those seeking the truth. “Fundamental research in physics gives us a privileged access to rationality and knowledge,” Professor Englert said in his concluding remarks. “As such, it may perhaps provide a bulwark against the invasion of dangerous and destructive ideologies...which is still threatening today against the violence they carry.”
What Inspires You?
Efim Zelmanov, Fields Medal (1994)
John Hopcroft, Turing Award (1986)
Martin Chalfie, Nobel Prize in Chemistry (2008)
Sir Tim Hunt, Nobel Prize in Physiology or Medicine (2001)
The first panel session of GYSS 2018 centred around the topic of inspiration - how the eminent scientists came to their chosen careers, research topics, and how they seek to inspire the next generation of researchers. The panelists shared their “origin stories” - from having encouraging teachers to high-school science fairs to trying out a variety of other careers first.
Questions were then opened up to the floor and GYSS participants sought answers to a variety of questions. These included: “What do you wish you knew when you first started your research?”, “How do you become an inspirational teacher?”, and “How do you overcome hardships?” There were also broader questions on science research ranging from “Do you think research is valued over education in academia” to “Should scientists take a political stand?”
The four panellists shared their wisdom and each offered their encouragement to the young scientists. Perhaps Sir Tim Hunt summed it up best and most concisely when he said, “Just keep going. If you don’t, you’re dead.”