Abstract
Optical clocks realize transition frequencies between atomic energy levels with a relative uncertainty below 10-18. Frequency ratio measurements between optical clocks can reach even lower uncertainties if systematic shifts are common mode for the atomic references like environmental disturbances or result from the same atomic parameter. This precision can be used to search for violations of local position invariance by exploiting the dependence of transition frequencies on fundamental constants like the fine structure constant α. An ion particularly suited to this task is 171Yb+
. It provides two optical clock transitions from the ground state to the first and second excited state, an electric octupole (E3) transition and an electric quadrupole (E2) transition, respectively. Because of the large mass of the ion, both transition frequencies show a large sensitivity on a variation of α and the difference in the electronic structure of the two excited states leads to a dependence of opposite sign. Repeated measurements of the ratio of the two transition frequencies provide the most stringent limits on temporal drifts of α and a potential dependence on the gravitational field [1]. To further enhance the performance of the 171Yb+ clocks and clearly distinguish clock shifts from variations of α, we employ 88Sr+ co-trapped in the same apparatus. 88Sr+ also features an E2 clock transition but its frequency only weakly depends on α. Furthermore, this ion can be used for sympathetic cooling and to investigate systematic frequency shifts of the 171Yb+ E3 transition on a magnified scale. We present progress towards combined clock operation with both species and a first precise measurement of the ratio of the 88Sr+ E2 and the 171Yb+ E3 transition frequencies. Here, we demonstrate an in-situ evaluation of the effective temperature of thermal radiation perturbing the ion and of oscillating magnetic fields using 88Sr+
.
. It provides two optical clock transitions from the ground state to the first and second excited state, an electric octupole (E3) transition and an electric quadrupole (E2) transition, respectively. Because of the large mass of the ion, both transition frequencies show a large sensitivity on a variation of α and the difference in the electronic structure of the two excited states leads to a dependence of opposite sign. Repeated measurements of the ratio of the two transition frequencies provide the most stringent limits on temporal drifts of α and a potential dependence on the gravitational field [1]. To further enhance the performance of the 171Yb+ clocks and clearly distinguish clock shifts from variations of α, we employ 88Sr+ co-trapped in the same apparatus. 88Sr+ also features an E2 clock transition but its frequency only weakly depends on α. Furthermore, this ion can be used for sympathetic cooling and to investigate systematic frequency shifts of the 171Yb+ E3 transition on a magnified scale. We present progress towards combined clock operation with both species and a first precise measurement of the ratio of the 88Sr+ E2 and the 171Yb+ E3 transition frequencies. Here, we demonstrate an in-situ evaluation of the effective temperature of thermal radiation perturbing the ion and of oscillating magnetic fields using 88Sr+
.
| Original language | English |
|---|---|
| Title of host publication | High-precision measurements and searches for New Physics |
| Subtitle of host publication | 766. WE-Heraeus-Seminar |
| Publisher | Wilhelm and Else Heraeus Foundation |
| Pages | 87-87 |
| Number of pages | 1 |
| Publication status | Published - 2022 |
| MoE publication type | Not Eligible |
| Event | 766. WE-Heraeus-Seminar: High-Precision Measurements and Searches for New Physics - Physikzentrum Bad Honnef, Bad Honnef, Germany Duration: 9 May 2022 → 13 May 2022 |
Conference
| Conference | 766. WE-Heraeus-Seminar: High-Precision Measurements and Searches for New Physics |
|---|---|
| Country/Territory | Germany |
| City | Bad Honnef |
| Period | 9/05/22 → 13/05/22 |