i n s i d e - Perimeter Institute

Kudos to ...Perimeter Institute congratulates Freddy Cachazo, who isthis year’s winner of the Rutherford Memorial Medal inPhysics from the Royal Society of Canada.didn’t want to grow up and face reality —I didn’t want to take a real job and haveto work. In hindsight, this was quite stupid— I ended up working nearly as hard. Butby then it was too late: nobody outsideacademia would give me a job. I admirepeople who make decisions. I’m not oneof them.NW: That’s remarkable. You never hadany doubts?GV: Well … The other day I went to pickup a cargo van, to go to the airportto collect some boxes with personalbelongings from Australia. I had so muchfun driving down the highway. And thatmakes you think … Anyway, the followingday I had to return the van to the rentalcompany, and that was kind of sad; itfelt like a kid saying goodbye to his bestfriend. I miss that cargo van.NW: So, if physics doesn’t work out, youcould be a trucker.GV: Yeah! Absolutely! Although, when Ithink about it, I’ve never been a very gooddriver …–Interview by Natasha Waxman*Editor’s note: An ansatz is a simplifiedmathematical model that makesassumptions that can be tested later.One of the Royal Society’s top honours, the RutherfordMedal recognizes outstanding research in any branch ofphysics. This is not Cachazo’s first such prize: In 2009, hewas awarded the Gribov Medal of the European PhysicalSociety.Cachazo is a superstring researcher working to understand nature’s mostfundamental constituents, but his work has attracted attention for its immediateusefulness in high-energy physics.Experimental high-energy physicists use accelerators to smash subatomicparticles together at near light speed, causing interactions which create newparticles. Outgoing particles are tracked,and these data are compared againstpredicted values to determine whethercurrent theory accounts for all of thephenomena observed.To set predicted values, scientists mustcalculate scattering amplitudes: theoreticalpredictions of what outgoing particlesare produced in what numbers in highenergy collisions. Calculating scatteringamplitudes has always been challenging,Photo credit: CERN but as accelerators have grown morepowerful, the problems have mounted.With the launch of the Large Hadron Collider at CERN, calculating scatteringamplitudes with traditional methods became practically infeasible.This is where Cachazo enters the picture. Drawing together ideas fromquantum field theory and complex analysis, Cachazo and his collaboratorsdeveloped new techniques for calculating scattering amplitudes that yieldresults far more simply and efficiently than was previously possible. Thesetechniques have already been widely adopted by experimentalists, and havebeen hailed as breakthroughs.But beyond its immediate utility, Cachazo’s work has also initiated a profoundshift in our understanding of quantum field theories. In developing the newmethods, Cachazo and his collaborators have uncovered surprising newmathematical structures. These structures may be clues that will lead to a muchdeeper understanding of how elementary particles arise, and the structure ofspacetime itself.Graduate student Hoan Dang has won a Vanier Canada Graduate Scholarshipfrom the Government of Canada. The scholarship is valued at $50,000 per year,for three years.Former graduate student Rowan Thomson has received a 2011 John CharlesPolanyi Prize in Physics from the Government of Ontario. The prize is valued at$20,000.fall FALL 2011 13