@article{be98c2a87bcb4140876601dbd2a62c1d,
title = "Test of the Einstein Equivalence Principle near the Galactic Center Supermassive Black Hole",
abstract = "During its orbit around the four million solar mass black hole Sagittarius A∗ the star S2 experiences significant changes in gravitational potential. We use this change of potential to test one part of the Einstein equivalence principle: the local position invariance (LPI). We study the dependency of different atomic transitions on the gravitational potential to give an upper limit on violations of the LPI. This is done by separately measuring the redshift from hydrogen and helium absorption lines in the stellar spectrum during its closest approach to the black hole. For this measurement we use radial velocity data from 2015 to 2018 and combine it with the gravitational potential at the position of S2, which is calculated from the precisely known orbit of S2 around the black hole. This results in a limit on a violation of the LPI of |βHe-βH|=(2.4±5.1)×10-2. The variation in potential that we probe with this measurement is six magnitudes larger than possible for measurements on Earth, and a factor of 10 larger than in experiments using white dwarfs. We are therefore testing the LPI in a regime where it has not been tested before.",
author = "{GRAVITY Collaboration} and A. Amorim and M. Baub{\"o}ck and Berger, {J. P.} and W. Brandner and Y. Cl{\'e}net and {Coud{\'e} Du Foresto}, V. and {De Zeeuw}, {P. T.} and J. Dexter and G. Duvert and M. Ebert and A. Eckart and F. Eisenhauer and {F{\"o}rster Schreiber}, {N. M.} and P. Garcia and F. Gao and E. Gendron and R. Genzel and S. Gillessen and M. Habibi and X. Haubois and Th Henning and S. Hippler and M. Horrobin and Z. Hubert and {Jim{\'e}nez Rosales}, A. and L. Jocou and P. Kervella and S. Lacour and V. Lapeyr{\`e}re and {Le Bouquin}, {J. B.} and P. L{\'e}na and T. Ott and T. Paumard and K. Perraut and G. Perrin and O. Pfuhl and S. Rabien and G. Rodr{\'i}guez-Coira and G. Rousset and S. Scheithauer and A. Sternberg and O. Straub and C. Straubmeier and E. Sturm and Tacconi, {L. J.} and F. Vincent and {Von Fellenberg}, S. and I. Waisberg and F. Widmann and E. Wieprecht",
note = "Publisher Copyright: {\textcopyright} 2019 American Physical Society.",
year = "2019",
month = mar,
day = "14",
doi = "10.1103/PhysRevLett.122.101102",
language = "אנגלית",
volume = "122",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "10",
}