EAS PhD Proposal Defense by Abhishek Ravishankar
Abstract:
The scientific potential of next-generation gravitational wave detectors, such as the LISA mission and the Einstein Telescope, relies heavily on the availability of waveform models that are both highly accurate and computationally efficient. This thesis proposes to advance the state of the art in waveform modeling by applying and developing surrogate modeling techniques to address these challenges, beginning with comparable-mass binary black holes (BBHs) and moving on to extreme mass ratio inspirals (EMRIs).
The first component of this research focuses on maximizing fidelity in precessing comparable-mass systems. While existing numerical relativity surrogates like NRSur7dq4 offer broad and reliable parameter coverage, there is accuracy to be gained in the ringdown, which is paramount for applications such as tests of general relativity. To address this, I introduced a domain-decomposition methodology that allows for targeted modeling choices in the inspiral and ringdown phases while preserving waveform smoothness. This methodology was employed to construct NRSur7dq4v2, which achieves a threefold increase in accuracy for extracting remnant black hole parameters compared to its predecessor.
The second component addresses the computational bottlenecks in modeling EMRIs. Current state-of-the-art waveform generation relies on calculating the trajectory of the secondary black hole driven by energy and angular momentum fluxes. This process is currently hindered by the need to interpolate between Teukolsky equation solutions over a dense grid in parameter space. To accelerate trajectory evolution, we propose to replace the direct interpolation of Teukolsky solutions with a surrogate model trained on the flux data.
I intend to go over the progress made in these directions, and plans to further these lines of investigation in the development of accurate surrogate models.
Advisors:
- Dr Vijay Varma, Department of Mathematics
- Dr. Scott Field, Department of Mathematics
Committee:
- Dr. Robert Fisher, Department of Physics
- Dr. Sigal Gottlieb, Department of Mathematics
TXT 105 - CSCDR
: Zoom
Dr.Vijay Varma
vvarma@umassd.edu
https://umassd.zoom.us/j/8338609915?pwd=dzlCMUIvdG5OZms3djl1UzlIaENYZz09