Posted by Rebecca Hastie on Jun 14, 2018
Eyal Schwartz is a Postdoctoral Fellow of the Dodd-Walls Centre for Photonic and Quantum Technologies at the University of Otago Department of Physics. He has a PhD in astronomy and astrophysics, and currently, Dr Schwartz’s focus is quantum mechanics. He is not from New Zealand, but has walked the length of the country on Te Araroa, and moved here 3 years ago. Eyal has since been busy giving presentations all over New Zealand, his very first talk was in Balclutha and now his last for a while as our community is fortunate to have him visit again three weeks before he leaves for the USA to work at LIGO for the next year to bring back even more knowledge of physics.
Eyal introduced us to the weird world of quantum mechanics by describing the photoelectric effect and the mysteries of electron characteristics with a Dr Quantum Double Slit Experiment YouTube video. Understanding waves and wavelengths was made more tangible (and tasty!) by showing us the wavelength of a microwave between the points at which it begins to melt a block of chocolate while stationary inside.
diagram from learned how scientists have considered the make up of atoms to differ throughout history, and how in the current quantum mechanical model we cannot know where a particle will be, only know the probability of it being at a point in any plane in the atom. Eyal summed up Heisenberg's uncertainty principle by explaining that the more accurately its position is known, the less accurately the particle's other properties such as velocity are known, adding to the mystery! As if he didn't have us confused and intrigued enough, he announced that we were only just getting to the weird part! Experiments with surprising results are a reminder to scientists to adjust their way of thinking about nature.
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The quantum world can be considered with Schrödinger's Cat but Eyal suggests an animal such as a possum that us Kiwis don't like as, being a quantum mechanics thought experiment, this animal in a box is both dead and alive, until it is observed!
This brought the presentation to the topic of antimatter, quantum tunnelling and, even weirder, quantum entanglement! Particles that are entangled can transfer their quantum state and affect the other instantaneously, no matter the distance between them. This contradicts Einstein's theory that nothing can travel faster than the speed of light and will be useful for quantum computation and creating secure communication and storage of information in huge capacity.
Particles can be entangled by cooling them to close to 0 degrees Kelvin, the lowest temperature possible where atoms have no kinetic energy. Atoms in the resulting gas cloud can no longer be distinguished from each other, forming another state of matter.
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Eyal explains the different states of matter and this form that has only recently been able to be manipulated, the Bose-Einstein condensate and bosenova. This state occurs when atoms reach temperatures colder than we could imagine being anywhere on Earth. Eyal at the Dodd-Walls Centre has been using lasers on atoms to cool them to 100-nano Kelvin. A laser might usually heat up an object, but in laser cooling the lasers have a specific wavelength that can knock electrons into different energy levels, eventually slowing the atom into ground state. This has allowed imaging of single atoms which 30 years ago Eyal was taught was not possible!
This technique is used with the future goal to make a quantum computer. Where in classic binary computers, units of information are either 1 or 0, in a quantum computer qubits would be in a superposition of both at once! Eyal discussed light computers and biological computers but says that quantum computing will be the way of the future.
Eyal explained that resistance can be a problem for new technologies, then demonstrated an amazing superconductor by cooling a metal ring with liquid nitrogen which repelled a piece of magnet, allowing it to levitate and continually rotate! This technology can be used to develop resistanceless transport such as the Maglev train which can reach speeds of 350km/h in Japan.
Eyal has a lot of answers to the magic of physics, but there are still so many more mysteries to understand. He leaves us with a quote by Richard P. Feynman "[Quantum mechanics] describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as She is - absurd."
While answering questions from the audience, Eyal gave us a bonus introduction to the theory of parallel universes, but as this would require at least another session, we'll just have to have him back again when he returns from the USA! Balclutha wishes Eyal all the very best at LIGO and we look forward to hearing of all the advances in his research when he is back in New Zealand.