RT Journal Article SR Electronic T1 Speed of sound from fundamental physical constants JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eabc8662 DO 10.1126/sciadv.abc8662 VO 6 IS 41 A1 Trachenko, K. A1 Monserrat, B. A1 Pickard, C. J. A1 Brazhkin, V. V. YR 2020 UL http://advances.sciencemag.org/content/6/41/eabc8662.abstract AB Two dimensionless fundamental physical constants, the fine structure constant α and the proton-to-electron mass ratio mpme, are attributed a particular importance from the point of view of nuclear synthesis, formation of heavy elements, planets, and life-supporting structures. Here, we show that a combination of these two constants results in a new dimensionless constant that provides the upper bound for the speed of sound in condensed phases, vu. We find that vuc=α(me2mp)12, where c is the speed of light in vacuum. We support this result by a large set of experimental data and first-principles computations for atomic hydrogen. Our result expands the current understanding of how fundamental constants can impose new bounds on important physical properties.