Jeremy Sakstein

Jeremy Sakstein's picture
University of Cambridge - Department of Applied Mathematics and Theoretical Physics (DAMTP)

Area of Research:

AFFILIATIONS

Department of Applied Mathematics and Theoretical Physics, University of Cambridge

Research Interests

My research focuses on astrophysical tests of modified gravity theories such as the chameleon and symmetron models. These theories allow for large deviations from Einstein's theory of General Relativity on large scales whilst screening out the modifications in our own solar system such that local bounds on modified gravity and the weak equivalence principle are satisfied.

My research has focused on the properties of stars in these theories, which may be unscreened and show novel effects in under-dense dwarf galaxies situated in cosmic voids. I have a computer code that can simulate the structure and evolution of stars in these theories with enough precision to allow a comparison with data. I also have a separate code that can calculate the new pulsation properties of these stars.

By comparing the inferred distances to unscreened dwarf galaxies measured using Cepheid and Tip of the Red Giant Branch stars my collaborators at UPenn and I were able to place new constraints on these theories. These are currently the strongest constraints in the literature.

A video of one of my talks on this subject can be found in the seminars section below.

I have also worked on supersymmetric models of modified gravity and have established a no-go theorem precluding the existence of supersymmetric symmetrons and rendering most other chameleon-like screening mechanisms observationally undetectable.

Positions Held

  • September 2013 - Present: Visiting Fellow, Perimeter Institute for Theoretical Physics
  • October 2010 - Present: Ph.D. Candidate, Department of Applied Mathematics and Theoretical Physics, University of Cambridge

Recent Publications

  • J. Sakstein, Stellar Oscillations in Modified Gravity, Phys. Rev. D, in press, arXiv: 1309.0495
  • P. Brax, A-C. Davis, J. Sakstein, Dynamics of Supersymmetric Chameleons, JCAP10(2013)007, arXiv: 1302.3080
  • P. Brax, A-C.Davis, J. Sakstein., SUPER-Screening, Phys. Lett. B 719 (2013) 210, arXiv: 1212.4392
  • B. Jain, V. Vikram & J. Sakstein, Astrophysical Tests of Gravity: Distance Indicators in the Nearby Universe, ApJ, in press, arXiv: 1204.6044
  • J. Sakstein, A. Pipino, J. E. G. Devriendt & R. Maiolino, The Origin and Evolution of the Mass-Metallicity relation using GalICS, Mon. Not. R. Astron. Soc. 410, 22032216 (2011), arXiv: 1008.4158
  • A-C. Davis, E.A. Lim, J. Sakstein & D.J. Shaw, Modified Gravity Makes Gravity Brighter, Phys. Rev. D 85, 123006 (2012), arXiv: 1102.5278

Seminars

  • Astrophysical Tests of Gravity October 2013 Lawrence Berkeley National Laboratory, CA, USA
  • Stellar Oscillations in Modified Gravity September 2013 COSMO 2013 DAMTP, Cambridge University, UK
  • Detecting Modified Gravity in the Stars May 2013 Centre for Astronomy and Particle Theory Nottingham University, UK
  • Detecting Modified Gravity in the Stars May 2013 UK Particle Cosmology Network Meeting Lancaster University, UK
  • Detecting Modified Gravity in the Stars April-May 2013 Case Western Reserve University, OH, USA; University at Buffalo, NY, USA; Columbia University, NY, USA; Princeton University, NJ, USA; Perimeter Institute for Theoretical Physics, Waterloo, ON, CA; Canadian Institute for Theoretical Astrophysics, Toronto, ON, Canada
  • Scalar-Tensor Screening Mechanisms April 2013 Invited talk, Novel Probes of Dark Energy and Modi ed Gravity Workshop University of Pennsylvania, PA, USA
  • Supersymmetric Chameleons September 2012 Gravity Beyond Einstein Institute of Physics London, UK
  • Detecting Dark Energy in the Stars June 2012 Department of Applied Mathematics and Theoretical Physics University of Cambridge, UK
  • Modified Gravity Makes Gravity Brighter September 2011 UK Particle Cosmology Network Meeting Institute of Cosmology and Gravitation Portsmouth University, UK
  • Modified Gravity Makes Gravity Brighter July 2011 PASCOS 2011 University of Cambridge, UK
  • Modified Gravity Makes Gravity Brighter March 2011 Department of Applied Mathematics and Theoretical Physics University of Cambridge, UK
  • PIRSA:13100132, Aspects of Modified Gravity, 2013-10-31, Cosmology & Gravitation
  • PIRSA:13050009, Detecting Modified Gravity in the Stars, 2013-05-14, Cosmology & Gravitation