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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

Massless particles are the backbone of our best theory of nature; the Standard Model of particle physics and gravity. In 2003, Witten combined 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. Finding a similar formulation for gravitons - particles with helicity plus or minus two - remained an important open problem until 2012 when 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 the existence of similar constructions in other dimensions. Such a general formulation could lead to a deeper understanding of field theory in general. String theory arguments hinted that six dimensions would be very special due to how bosons and fermions interact. In 2013 and in collaboration with S. He (a PI postdoctoral fellow) and E. Yuan (a PI graduate student), I searched for such a six dimensional construction but could not find it with the tools available at the time. Instead we found a construction for bosons in arbitrary dimensions. This is now known as the CHY construction and it gives tree-level scattering matrices of a large variety of theories, including gluons and gravitons, in any dimension as integrals over the space of n-punctured spheres. In May of 2018, and in collaboration with researchers at Caltech and Queen Mary University, my team at PI found the six dimensional analog of Witten"s four-dimensional construction in a way that bosons and fermions are treated symmetrically, i.e., we found a supersymmetric formulation.

- 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]].
- 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, A. Postnikov and J. Trnka, On-Shell Structures of MHV Amplitudes Beyond the Planar Limit, JHEP 1506, 179 (2015) [arXiv: 1412.8475 [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 and D. Skinner, Gravity from Rational Curves, Phys. Rev. Lett. 110, 161301 (2013) [arXiv: 1207.0741 [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, A. Guevara, M. Heydeman, S. Mizera, J. H. Schwarz and C. Wen, The S Matrix of 6D Super Yang-Mills and Maximal Supergravity from Rational Maps, arXiv: 1805.11111 [hep-th].
- F. Cachazo, Combinatorial Factorization, arXiv: 1710.04558 [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 in Three Dimensions from Rational Maps, arXiv: 1306.2962 [hep-th].
- F. Cachazo, S. He and E. Y. Yuan, Scattering Equations and KLT Orthogonality, arXiv: 1306.6575 [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

- Invited talk at the Annual Canadian Association of Physicists (CAP) Congress. "From the NLSM to the Probe M5-brane". Dalhousie University. Halifax, NS, June 2018
- Tutte Colloquium: "Combinatorics in Scattering Amplitudes", Department of Combinatorics and Optimization. University of Waterloo. May 2018
- Inaugural Math Science Lectures in Honor of Raoul Bott: "Geometry and Combinatorics in Particle Interactions". Series of two lectures at the Harvard University Center of Mathematical Sciences and Applications (CMSA). April 2018
- Series of four lectures at the CERN Winter School on Supergravity, Strings and Gauge Theory 2018. CERN, Geneva, Switzerland. February 2018.
- Series of five lectures at the Kavli Asian Winter School on Strings, Particles and Cosmology 2018. International Centre for Theoretical Sciences (ICTS), Bangalore, India. January 2018.
- Plenary talk on ``Amplitudes from Riemann Spheres", LoopFest XV, University of Buffalo, NY, USA, August 2016.
- Plenary talk on ``Unification and Extension", Theory CANADA 11, Carleton University, Ottawa, Canada, June 2016.
- Plenary talk on ``S-Matrix Theory", Canadian Association of Physicist Congress, University of 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.
- Plenary talk at PASCOS 2015, Abdus Salam ICTP, Trieste, Italy, June 2015
- Five lectures at TASI 2015 "New Frontiers in Fields and Strings", University of Colorado, Colorado, USA, June 2015
- Plenary talk at Amplitudes 2015, EHT, Zurich, Switzerland, June 2015
- Series of three lectures given at the Spring School on Superstring Theory and Related Topics. Abdus Salam ICTP, Trieste, Italy, March 2015
- Colloquium. Department of Physics, University of Toronto, Toronto, Canada, March 2015
- Plenary talk at STRINGS 2014 in Princeton USA.
- Plenary talk at Quantum Gravity in Paris 2014. Paris. March 2014.
- PIRSA:18040049, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 17, 2018-04-27, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040048, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 16, 2018-04-26, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040047, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 15, 2018-04-25, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040046, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 14, 2018-04-24, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040045, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 13, 2018-04-23, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040044, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 12, 2018-04-20, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040040, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 6, 2018-04-16, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040133, Welcome and Opening Remarks, 2018-04-16, New Directions in Conventional and Ambitwistor String Theories
- PIRSA:18040039, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 5, 2018-04-13, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040038, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 4, 2018-04-12, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040037, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 3, 2018-04-11, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040036, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 2, 2018-04-10, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- PIRSA:18040035, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory - Lecture 1, 2018-04-09, PSI 2017/2018 - Scattering Amplitudes in QFT & String Theory (Cachazo)
- 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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