In this Letter we show that multiband observations of stellar-mass binary black holes by the next generation of ground-based observatories (3G) and the space-based Laser Interferometer Space Antenna (LISA) would facilitate a comprehensive test of general relativity by simultaneously measuring all the post-Newtonian (PN) coefficients. Multiband observations would measure most of the known PN phasing coefficients to an accuracy below a few percent---two orders-of-magnitude better than the best bounds achievable from even `golden' binaries in the 3G or LISA bands. Such multiparameter bounds would play a pivotal role in constraining the parameter space of modified theories of gravity beyond general relativity.
@article{arxiv.2005.09607,
title = {Multiparameter tests of general relativity using multiband gravitational-wave observations},
author = {Anuradha Gupta and Sayantani Datta and Shilpa Kastha and Ssohrab Borhanian and K. G. Arun and B. S. Sathyaprakash},
journal= {arXiv preprint arXiv:2005.09607},
year = {2020}
}