Cosmology Master's student at University of Helsinki

Physics Days 2024

Exploring the gravitational wave power spectrum from first-order phase transitions

Thank you for viewing my poster at Physics Days! You can find a PDF of the poster here.

If you want to try out PTPlot online yourself, visit There you will also find additional information about the code. Currently, the online version supports calculating the power spectrum with the broken power-law ansazt, but we are working on adding the Sound Shell Model approach as well.


  1. The LISA mission is a collaboration of the LISA Consortium, ESA and NASA.
  2. PTPlot is a tool for exploring the gravitational wave power spectrum from first-order phase transitions, and evaluating the likelihood of detecting a signal with the LISA mission. The source for PTPlot is available at Bitbucket.
  3. Chiara Caprini et al., Detecting gravitational waves from cosmological phase transitions with LISA: an update, JCAP 03 (2020) 024, arXiv:1910.13125 [astro-ph.CO]
  4. Mark Hindmarsh, Stephan J. Huber, Kari Rummukainen, and David J. Weir, Shape of the acoustic gravitational wave power spectrum from a first order phase transition, Phys. Rev. D 96 (2017) 103520, Phys. Rev. D 101 (2020) 089902 (Erratum), arXiv:1704.05871 [astro-ph.CO]
  5. PTtools is Python library for calculating hydrodynamical quantities around expanding bubbles of the new phase in an early universe phase transition, and the resulting gravitational wave power spectrum in the Sound Shell Model. It will be published soon at
  6. Mark Hindmarsh and Mulham Hijazi, Gravitational waves from first order cosmological phase transitions in the Sound Shell Model, JCAP 12 (2019) 062, arXiv:1909.10040 [astro-ph.CO]
  7. The benchmark points for the SNR plots were for supersymmetry (SUSY) embeddings with chiral supersinglets or supertriplets (supplied by G. Nardini). More information about these can be found from the PTPlot website benchmark model 9 Some SUSY embeddings.