To see open hosted preprints and journal articles follow the inSPIRE link in the sidebar, or click here.

My group’s web page is hosted at, where you can find my recent grant proposals here.

Big Questions:

  • What unifies our physical predictions?
  • How does the relatively calm macroscopic universe survive and emerge from the violent quantum fluctuations of its underlying microphysics?
  • How do classical notions of space and time emerge from fundamental principles, and what governs their evolution?
  • How are should our classical understanding of space and time be modified to build intuition of underlying quantum reality?
  • How might our current understanding of quantum mechanics need to evolve to resolve answers to the above questions?

Broad projects:

  • Double copy unification of relativistic quantum field theories.
  • Double copy relevance for classical predictions in perturbative gravity.
  • Predictivity question re: pointlike quantum field theories of gravity. (Are all QFT of gravity effective out of necessity?)
  • Relevance of field-theory double-copy to ultra-soft properties of string theory. (See Z-theory.)
  • Effective field theory of large scale structure (EFTofLSS)
  • -Attractor Inflationary models.

Research highlights:

  • Discovered the color-kinematic duality in gauge theories and the associated double-copy structure of tree and multi-loop gravity theory amplitudes. Importance: Striking clarification of the intimacy between gauge and gravity theories, redundancy present in both, changing the way we calculate in and think about these theories. (For a textbook introduction can now see Anthony Zee’s Quantum Field Theory in a Nutshell, 2nd Ed., Chapter N.4. For popular science account see May 2012 cover story of Scientific American.)
    with: Bern, Johansson.
  • Discovered the basis (“BCJ” basis) of gauge-theory tree-level amplitudes. Importance: Led to proofs of explicit tree-level gauge-gravity amplitude-level relations (KLT) in field theory, subsequent discovery of analogous structure in string theory led to closed form string-KLT expressions and all-order expressions for string tree-amplitudes.
    with: Bern, Johansson.
  • Established, through explicit calculation, that the high energy behavior of maximal supergravity, contrary to popular opinion, is much better than expected – matching the known finite maximal gauge theory – through 4 loops as of now. Importance: If finite to all orders it is because of an unrecognized symmetry or mechanism whose apprehension will teach something very new about gravity.
    with: Bern, Dixon, Kososwer, Roiban, Johansson.
  • Established the predictive impact of certain anomalies relevant to supergravity theories, and perhaps more strikingly their underlying double-copy origins. Importance: There is mounting evidence to suggest that failure of predictivity for pure supergravity theories in four-dimensions are directly related to these anomalies, which * do not exist for supergravity theories.*
    with: Kallosh, Roiban, Tseytlin.
  • Established the effective field theory of cosmological large-scale structure. Importance: opens up a rigorous new way to analytically study large-scale structure taking into account the nonlinearity of small-scale perturbations with telling agreement between numerical simulations and analytic theory.
    with: Foreman, Green, Hertzberg, Senatore.
  • Discovered a systematic, theory-independent, approach to unitarity-based multi-loop perturbative quantization - Method of Maximal Cuts. Importance: Establishes hierarchy of relevance of -matrix information for a given theory. Trivialized unitarity state-sums for theories whose spectra are truncations of super Yang-Mills1 in 4D to just tracking glue around MHV-vertex graphs.
    with: Bern, Dixon, Kosower, Roiban, Johansson.
  • Established covariant prescriptions for deforming non-linear duality-invariant theories. Importance: demonstration of freedom to introduce counterterms to theories protected by duality-invariance, may be relevant to UV questions in gravity.
    with: Broedel, Ferrara, Kallosh, Roiban
  • Established Z-theory as the effective bi-colored scalar theory which encodes all the corrections of the open-string, and thus encodes all the ultra-soft UV behavior. Importance: Scalars theories are technically much simpler to analyze. Z-theory amplitudes offer a fascinating laboratory to study the emergence of stringy-behavior in a new and technically much simpler context.
    with: Mafra and Schlotterer
  1. So, also, theories that are orbifolds of supergravity. 

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