Maximilian Abitbol

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Maximilian Abitbol

Beecroft Fellow in Theoretical Cosmology

I started as a Beecroft Fellow in October 2018 after receiving my Ph.D. in physics from Columbia University. My dissertation spanned several topics related to the cosmic microwave background (CMB). In particular, I studied systematic errors that effect CMB experiments, forecasted capabilities for future experiments, performed data analysis for a balloon-borne experiment called EBEX, and worked on readout technology for kinetic inductance detectors. Currently my research is focused on using CMB data to reveal information about the beginning of the Universe. I was selected as a Dennis Sciama Junior Research Fellow at Wolfson College in the beginning of 2020 (

The goal of many modern CMB experiments is to detect evidence for inflation; a process believed to occur during the first fraction of a second that produced a rapid expansion of space. Inflation provides a mechanism to seed the initial density fluctuations throughout the Universe, which grow into all the observable structure that we see today. The inflationary process not only creates density fluctuations but also predicts a background of gravitational waves. These primordial gravitational waves leave an imprint that is observable as a parity-violating signature in the polarization of the CMB, called B-modes. A detection of primordial B-modes would provide strong evidence that the Universe began with an inflationary epoch, resolving one of the largest outstanding questions in cosmology.

My publications can be found on arXiv or on NASA ADS

My personal website
My github

Tutor for Queen's College, Oxford:

  • F2018-S2019: Electricity, Magnetism and Optics.

Teaching Assistant in physics at Columbia:

  • F2016-S2018: Advanced Physics Lab
  • S2016-S2017: Electromagnetic Waves and Optics
  • S2015-F2016: General Physics
  • F2015: Classical and Quantum Waves
  • F2014-S2015: Physics TA Preceptor
  • F2013-S2015: General Physics Lab

Teaching Assistant in math at Johns Hopkins University:

  • S2014: Differential Equations
  • F2012: Linear Algebra
  • S2012: Vector Calculus (III)
  • F2011: Calculus (II)

My research focus is in data analysis methods for cosmic microwave background experiments. In particular I am working on foreground subtraction to enable B-mode science with the Simons Observatory.

In order to detect the B-mode signal, precise measurements must be made that require the use of specialized telescopes in space or regions with low atmospheric emission. The primary challenge in identifying B-modes comes from the fact that our observations necessarily include contamination from our Galaxy. Thermally emitting dust particles in the Milky Way and cosmic rays spiraling in the Galactic magnetic field produce microwave radiation in the same frequency range as the CMB. These signals must be identified and subtracted to enable a detection of primordial B-modes. This analysis requires applying physical and statistical considerations to combine our understanding of astrophysics with our knowledge of the telescope.

One of the largest new experiments in the field is the Simons Observatory, a set of telescopes being built in the Atacama Desert in Chile for the purpose of measuring the B-mode inflationary signal. David Alonso and I are members of this collaboration and are leading the B-mode analysis effort. We are also members of the Atacama Cosmology Telescope, which has been making observations of the CMB since 2007.

Another way to study the early Universe is to investigate the thermal evolution of the CMB. A variety of physical processes in the early Universe are tightly coupled to the CMB and produce faint but observable signals in the CMB frequency spectrum. These signals are called CMB spectral distortions, as they are distortions from the blackbody spectrum that is produced by radiation and matter in thermal equilibrium. Spectral distortions can be created by a variety of non-equilibrium processes, including for example the difference in the cooling rates of matter and radiation from the expansion of the Universe. We could also detect several non-standard cosmological scenarios such the existence of primordial blackholes using spectral distortions. To this end I am studying how one could design an experiment to measure CMB spectral distortions and have forecasted the capabilities for several missions proposed to NASA and the ESA.

Please see my arXiv page here: arXiv
or my ADS library here: ADSABS