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- Freddy Cachazo

Gluskin Sheff Freeman Dyson Chair in Theoretical Physics at Perimeter Institute

Areas of Research:

Phone: (519) 569-7600 x8501

In recent years it has become clear that the scattering matrix of massless particles is a very special object. Massless particles are the backbone of our best theory of nature; the Standard Model of particle physics and gravity. In 2003, Witten succeeded in combining twistor theory and string theory to produce a new formulation for the scattering matrix of gauge bosons - massless particles of helicity plus or minus one. Since then finding a similar formulation for gravitons - particles with helicity plus or minus two - has been a very important open problem. In 2012, in collaboration with Y. Geyer (a PSI student), I found one such formulation. Not long after this first formulation was found, I found a second one with D. Skinner (a PI postdoctoral fellow). All these constructions are based on four dimensional kinematics. A natural question is whether similar constructions can be found in any dimension. Such a general formulation could lead to a deeper understanding of field theory in general. In 2013 and in collaboration with E. Yuan (a PI graduate student) and S. He (a PI postdoctoral fellow), I found such a construction. This is now known as the CHY construction and it gives tree-level scattering matrices of a variety of theories, including gluons and gravitons, in any dimensions as integrals over the space of n-punctured spheres. This new formulation has become an active area of research. In 2014 our group found CHY representations for theories such as Dirac-Born-Infeld and Galileons. In 2016, we found extensions of the theory of pions using soft limits which were previously hidden and become manifest using their CHY formulation. Very recently, my team has been exploring the application of these techniques to classical gravitational scattering with views to applications to the binary merger of black hole problem.

- September 2009 - June 2010 School of Natural Sciences. Institute for Advanced Study. Princeton NJ. Member.
- 2005-present. Perimeter Institute. Faculty Member
- 2002-2005 School of Natural Sciences. Institute for Advanced Study. Princeton NJ. Postdoctoral Member.

- 2016 CAP-CRM Prize in Theoretical and Mathematical Physics.
- 2014 New Horizons Prize (FPP).
- 2012 Herzberg Medal (CAP).
- 2011 Rutherford Medal, Royal Society of Canada (RSC).
- 2009 Gribov Medal, European Physical Society (EPS)
- Early Reseach Award of Ontario (ERA).

- F. Cachazo, S. Mizera and G. Zhang, Scattering Equations: Real Solutions and Particles on a Line, JHEP 1703, 151 (2017) [arXiv: 1609.00008 [hep-th]].
- F. Cachazo, P. Cha and S. Mizera, Extensions of Theories from Soft Limits, JHEP 1606, 170 (2016) [arXiv: 1604.03893 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, One-Loop Corrections from Higher Dimensional Tree Amplitudes, JHEP 1608, 008 (2016) [arXiv: 1512.05001 [hep-th]].
- N. Arkani-Hamed, J. L. Bourjaily, F. Cachazo, A. Postnikov and J. Trnka, On-Shell Structures of MHV Amplitudes Beyond the Planar Limit, JHEP 1506, 179 (2015) [arXiv: 1412.8475 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, Scattering Equations and Matrices: From Einstein To Yang-Mills, DBI and NLSM, JHEP 1507, 149 (2015) [arXiv: 1412.3479 [hep-th]].
- N. Arkani-Hamed, J. L. Bourjaily, F. Cachazo and J. Trnka, Singularity Structure of Maximally Supersymmetric Scattering Amplitudes, Phys. Rev. Lett. 113, no. 26, 261603 (2014) [arXiv: 1410.0354 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, Einstein-Yang-Mills Scattering Amplitudes From Scattering Equations, JHEP 1501 (2015) 121 [arXiv: 1409.8256 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, Scattering of Massless Particles: Scalars, Gluons and Gravitons, JHEP 1407, 033 (2014) [arXiv: 1309.0885 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, Scattering of Massless Particles in Arbitrary Dimensions, Phys. Rev. Lett. 113, no. 17, 171601 (2014) [arXiv: 1307.2199 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, Scattering in Three Dimensions from Rational Maps, JHEP 1310, 141 (2013) [arXiv: 1306.2962 [hep-th]].
- F. Cachazo, S. He and E. Y. Yuan, Scattering equations and Kawai-Lewellen-Tye orthogonality, Phys. Rev. D 90, no. 6, 065001 (2014) [arXiv: 1306.6575 [hep-th]].
- F. Cachazo, L. Mason and D. Skinner, Gravity in Twistor Space and its Grassmannian Formulation, SIGMA 10, 051 (2014) [arXiv: 1207.4712 [hep-th]].
- F. Cachazo and D. Skinner, Gravity from Rational Curves, Phys. Rev. Lett. 110, 161301 (2013) [arXiv: 1207.0741 [hep-th]].
- F. Cachazo and A. Guevara, Leading Singularities and Classical Gravitational Scattering, arXiv: 1705.10262 [hep-th].
- F. Cachazo and G. Zhang, Minimal Basis in Four Dimensions and Scalar Blocks, arXiv: 1601.06305 [hep-th].
- F. Cachazo and H. Gomez, Computation of Contour Integrals on {\cal M}_{0,n}, arXiv: 1505.03571 [hep-th].
- F. Cachazo, S. He and E. Y. Yuan, New Double Soft Emission Theorems, arXiv: 1503.04816 [hep-th].
- F. Cachazo and E. Y. Yuan, Are Soft Theorems Renormalized?, arXiv: 1405.3413 [hep-th].
- F. Cachazo and A. Strominger, Evidence for a New Soft Graviton Theorem, arXiv: 1404.4091 [hep-th].
- F. Cachazo, S. He and E. Y. Yuan, Scattering of Massless Particles in Arbitrary Dimension, arXiv: 1307.2199 [hep-th].
- F. Cachazo, S. He and E. Y. Yuan, Scattering Equations and KLT Orthogonality, arXiv: 1306.6575 [hep-th].
- F. Cachazo, S. He and E. Y. Yuan, Scattering in Three Dimensions from Rational Maps, arXiv: 1306.2962 [hep-th].
- F. Cachazo, Resultants and Gravity Amplitudes, arXiv: 1301.3970 [hep-th].
- Grassmannian Geometry of Scattering Amplitudes, N. Arkani-Hamed, J. Bourjaily, F. Cachazo, A. Goncharov, A. Postnikov, J. Trnka, Cambridge University Press, 2016

- Plenary talk on ``Amplitudes from Riemann Spheres", LoopFest XV, University of Buffalo, NY, USA, August 2016.
- Plenary talk on ``S-Matrix Theory", Canadian Association of Physicist Congress, University of Ottawa, Canada, June 2016.
- Plenary talk on ``Unification and Extension", Theory CANADA 11, Carleton University, Ottawa, Canada, June 2016.
- Plenary talk on "Developments in String and Field Theory" at the European Physical Society 2015 meeting in Vienna, Austria, July 2015.
- Five lectures at TASI 2015 "New Frontiers in Fields and Strings", University of Colorado, Colorado, USA, June 2015
- Plenary talk at PASCOS 2015, Abdus Salam ICTP, Trieste, Italy, June 2015
- Plenary talk at Amplitudes 2015, EHT, Zurich, Switzerland, June 2015
- Colloquium. Department of Physics, University of Toronto, Toronto, Canada, March 2015
- Series of three lectures given at the Spring School on Superstring Theory and Related Topics. Abdus Salam ICTP, Trieste, Italy, March 2015
- Plenary talk at STRINGS 2014 in Princeton USA.
- Plenary talk at Quantum Gravity in Paris 2014. Paris. March 2014.
- Academics Program Department Presentation to the Scientific Advisory Committee, October 2015.
- PIRSA:15060045, Welcome to Convergence - Opening Panel: Physics Today, 2015-06-22, Convergence
- PIRSA:15050055, Scattering Amplitudes and Riemann Surfaces, 2015-05-27, Geometry and Physics 2015
- PIRSA:15050063, Scattering Amplitudes and Riemann Surfaces, 2015-05-26, Geometry and Physics 2015
- PIRSA:15050047, Scattering Amplitudes and Riemann Surfaces, 2015-05-25, Geometry and Physics 2015
- PIRSA:14100026, 14/15 PSI - Conformal Field Theory - Lecture 14, 2014-10-24, 14/15 PSI - Conformal Field Theory
- PIRSA:14100025, 14/15 PSI - Conformal Field Theory - Lecture 13 , 2014-10-23, 14/15 PSI - Conformal Field Theory
- PIRSA:14100024, 14/15 PSI - Conformal Field Theory - Lecture 12 , 2014-10-22, 14/15 PSI - Conformal Field Theory
- PIRSA:14100023, 14/15 PSI - Conformal Field Theory - Lecture 11 , 2014-10-21, 14/15 PSI - Conformal Field Theory
- PIRSA:14100022, 14/15 PSI - Conformal Field Theory - Lecture 10, 2014-10-20, 14/15 PSI - Conformal Field Theory
- Quantum Gravity Group Meeting. Resultants and Gravity Amplitudes.

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