Trace anomaly contribution to hydrogen atom mass

We compute trace anomaly contribution to hydrogen atom mass, which turns out to be related to the part of the Lamb shift. To the best of our knowledge, this is a first model independent calculation of trace anomaly contribution to a bound state. This finding might shed new light on our understandings of the mass structure of QCD bound states, such as, heavy quarkonium.

Figure 1

Trace anomaly contribution (diagram a) and the vacuum polarization diagram with the mass operator insertion (diagram b). Black dots represent the interaction with Coulomb potential.

Figure 2

NLO corrections to the electron mass term.

Figure 3

Part of the NLO correction to the electron mass term in NRQED in vacuum (diagram a), and that in the bound state (diagram b).