the Perimeter fall/winter 2019/20 10 years of PSI When computing meets physics More fast radio bursts! Martin Rees on stars, science & resilience ... and much more Editor Natasha Waxman [email protected] Managing Editor Tenille Bonoguore Contributing Authors Tenille Bonoguore Erin Bow Mike Brown Colin Hunter Stephanie Keating Roger Melko Robert Myers Copy Editors Tenille Bonoguore Erin Bow Mike Brown Colin Hunter Stephanie Keating Charlotte Prong Natasha Waxman Emily Youers Graphic Design Gabriela Secara Photo Credits Adobe Stock Breakthrough Prize Stephanie Keating Gabriela Secara Inside the Perimeter is published by Perimeter Institute for Theoretical Physics. www.perimeterinstitute.ca 31 Caroline Street North, Waterloo, Ontario, Canada p: 519.569.7600 I f: 519.569.7611 02 IN THIS ISSUE 04/ New Horizons, Robert Myers 06/ Perimeter researchers win Breakthrough and New Horizons prizes, Mike Brown 08/ Compound interest: Researchers flourish in the overlap between math and physics, Erin Bow 09/ Krembil Foundation elevates its commitment 11/ Celebrating 10 years of Perimeter Scholars International, Stephanie Keating 13/ Computing meets physics 14/ CHIME lives up to its promise – and then some, Erin Bow and Stephanie Keating 16/ The new science of cause and effect, Tenille Bonoguore 19/ Data wizard Dustin Lang, Colin Hunter 21/ The rise and rise of machine learning, Tenille Bonoguore 23/ A new paradigm for artificial intelligence and physics,Roger Melko 26/ Upcoming conferences 27/ Martin Rees on stars, science, and signs of life, Colin Hunter 29/ Back on the bus with ISSYP, Stephanie Keating 32/ Thanks to our supporters 34/ Inaugural program gives undergrads a glimpse of research life, Stephanie Keating 36/ Where did it come from? Digital computing, Erin Bow 40/ Particles 42/ PI kids are asking: What is the smallest thing in the universe?, Stephanie Keating 03 NEW HORIZONS When people talk about Perimeter, Meanwhile, fields like cosmology (page 14). Several years ago, Kendrick they often mention the Institute’s age: – once a data-starved science that Smith, who holds the Daniel Family our doors have been open for less sometimes stumbled in the dark – are James Peebles Chair, basically spent than 20 years. now swimming in data, even at times a year reworking the data pipeline overwhelmed by data. Computational for the CHIME experiment. This made I get it. Compared to peers like the scientists like Kendrick Smith and the telescope vastly more efficient and Institute for Advanced Study (founded Dustin Lang (profiled on page 19) are brought new problems into reach. in 1930) or Stanford (1885) or even bringing the field into focus. That done, Kendrick led a Perimeter Cambridge (1209), Perimeter is very team in developing new mathematical young and many have found our rapid Perimeter is built to be a place where techniques that enabled CHIME to rise onto the world stage of science this new kind of work can thrive. We conduct a new real-time, needle-in- surprising. deliberately choose to take diverse a-haystack search needed to capture – even contrasting – approaches to fast radio bursts, mysterious energetic But I think it’s important to balance the fundamental problems. We believe pulses of radio-frequency light “young Perimeter” story with another that interesting things happen at originating in deep space. one: in the world of theoretical physics, intersections, and we do everything we 20 years is a long time. It’s astonishing can to make it easy for our researchers At a university, a young faculty member how much of the research conducted to talk across fields, to communicate like Kendrick might have felt the at Perimeter today would have been from one area to another, to build pressure to publish fresh data analysis, impossible, even unthinkable, 20 or diverse collaborations. We don’t worry rather than spending a year reworking 10 or even five years ago. too much about where the boundaries software and inventing new analysis between subfields are. We just walk methods. Instead, we say to our young For instance, I think the intersection right through them. faculty members: don’t think about of computers and physics, featured in publication rates and citation numbers. this issue, is richer and more surprising Take the new Perimeter Institute Think about how you can really have than anyone foresaw. The machine Quantum Information Lab (PIQuIL). an impact. learning conference featured on page Featured on page 23, PIQuIL is a 21 shows how ideas from computer new venture that joins researchers with In my new role as Perimeter’s science and information theory are students, industry, and government director, I’m frequently asked what informing physics. The work on causal partners in a truly exciting mash-up at all the work we do is good for. When inference featured on page 16 shows the intersection of artificial intelligence I field this question, I’m reminded how ideas from quantum foundations and quantum computing. of J.J. Thomson. In 1897, Thomson are informing information science. discovered the electron, which at the In other words, the intersection goes Or, take the story on the latest time was of no use whatsoever – so both ways. discoveries from the CHIME telescope much so that he once memorably 04 made a toast to “the useless electron.” In 1934, in the teeth of the Great Depression, when people were calling for a halt to basic research and a focus on immediate problems, Thomson reminded people that his discovery had turned out to be pretty useful (after all, it’s the foundation of electronics). He said, “Any new discovery contains the germ of a new industry.” If I were to guess what impact today’s fundamental research will have on the future, I’d be wrong – even comically wrong – because predicting the impact of fundamental physics always falls short of reality. The big discoveries literally transform the world around us. It is vitally important that we do daring research into uncharted places. Why? Because if we focus only on immediate problems, we will never move past the horizon set by those problems. The horizon of our imaginations is so much bigger than that. The horizon of what is possible is bigger still – and moving fast. Here’s to our new horizons. – Robert Myers, Perimeter Director and BMO Financial Group Isaac Newton Chair 05 PERIMETER RESEARCHERS WIN BREAKTHROUGH AND NEW HORIZONS PRIZES Science’s richest awards, presented at a glittering ceremony in California, cap off a stellar year for Perimeter researchers. In April, the Event Horizon Telescope (EHT) collaboration unveiled the first-ever image of a black hole’s event horizon, a breakthrough that captured imaginations and made headlines around the world. That image – and the avenues for discovery it opens up – has now earned the team one of the field’s most prestigious prizes: the Breakthrough Prize in Fundamental Physics. The $3 million (USD) prize was split equally among 347 scientists across 60 institutions in 20 countries. Perimeter Associate Faculty member Avery Broderick, who holds the Delaney Family John Archibald Wheeler Chair at Perimeter and leads the Institute’s EHT Initiative, was a key leader in the collaboration, providing much of the theory that went into the image. Kendrick Smith 06 With him in the Breakthrough team were Perimeter Associate Faculty member Ue-Li Pen, postdoctoral researcher Hung-Yi Pu, PhD student Paul Tiede, and associate PhD students Boris Georgiev, Britton Jeter, and Chunchong (Rufus) Ni. Former Perimeter postdoctoral researchers Jorge A. Preciado-Lopez and Roman Gold we+re also among the winners, as were former PhD student Mansour Karami. Perimeter is one of 13 partner organizations in the EHT collaboration – and the only Canadian one. “We now stand at the beginning of an empirical era of black hole science that a decade ago would be considered science fiction,” said Broderick, who is cross-appointed with the University of Waterloo. “We look forward with enormous excitement to being part of the steady stream of transformative results over the next many years.” This marks the second time in the Breakthrough Prize’s nine-year history that Perimeter researchers have been honoured with the award. Kendrick Smith, who holds the Daniel Family James Peebles Chair, shared in the 2018 prize awarded to the Wilkinson Microwave Anisotropy Probe. Smith was honoured again this year, as one of two Perimeter scientists to earn a New Horizons in Physics Prize from the Breakthrough Prize Foundation. The New Horizons awards recognize early-career scientists making important progress on fundamental problems. Smith and two colleagues were honoured “for the development of novel techniques to extract fundamental physics from astronomical data.” Smith was a leading researcher in this year’s landmark detections of an unprecedented number of fast radio bursts by Canada’s CHIME telescope. (See story on page 14.) Pedro Vieira, who holds the Clay Riddell Paul Dirac Chair, and Visiting Fellow Simon Caron-Huot were recognized “for profound contributions to the understanding of quantum field theory.” Vieira is blazing rich new conceptual paths to understanding the language that describes nature at its most fundamental level. Perimeter researchers have won seven New Horizons Prizes since the award’s inception, more than any other institution in the world. – Mike Brown Pedro Vieira Avery Broderick 07 Kevin Costello (left) and Davide Gaiotto chat in the Perimeter atrium. Compound interest: Researchers flourish in the overlap between math and physics Whether they are probing higher dimensions or trampling over boundaries, Kevin Costello and Davide Gaiotto are having a blast – and making breakthroughs. Physicists say the universe is a book written in the language And then there’s Kevin Costello and Davide Gaiotto. One is of mathematics. Mathematicians aren’t sure why physicists a mathematician, the other a physicist, and together, they’re a are only interested in that one book.