Yes, but there's still an assumption that 'quantum time', as measured by your cesium atoms -- when moving along world lines -- remains constant. I.e., axiom: world-line time = quantum time. What if this weren't so ? What if the time measured by gravitational orbits *didn't match* quantum time -- i.e., it changed ever so slightly over billions of years ? Could such a difference look like "expansion" ? At 11:27 AM 5/23/2016, Brent Meeker wrote:
"Quantum times" are just proper time measured along world lines. GR allows that the spacetime is curved so locally parallel world lines don't remain parallel, but there is no other effect on the rate of atomic phenomena. Along it's own world line every cesium atom keeps the same time (i.e. is an ideal clock).