Abstract
We describe a new technique to estimate variations in the fundamental constants using 18 cm OH absorption lines, with the advantage that all lines arise in the same species, allowing a clean comparison between the measured redshifts. In conjunction with one additional transition, it is possible to simultaneously measure changes in , , and . We use the 1665 and 1667 MHz line redshifts in conjunction with those of HI 21 cm and mm-wave molecular absorption in a gravitational lens at to constrain changes in the three parameters over the redshift range . While the constraints are relatively weak ( part in ), this is the first simultaneous constraint on the variation of all three parameters. Either one (or more) of , , and must vary with cosmological time or there must be systematic velocity offsets between the OH, , and HI absorbing clouds.
- Received 2 June 2003
DOI:https://doi.org/10.1103/PhysRevLett.91.241302
©2003 American Physical Society