Speakers
Description
The complexity and variety of molecules offer promising applications in metrology and quantum information that go beyond what is possible with atomic systems. We aim to study light molecular ions that are amongst the most fundamental and simplest molecules. Their internal structure can be calculated, making them prime candidates for the determination of fundamental constants as well as for theory benchmarks.
Spectroscopy of single ions is expected to reduce systematic uncertainties and improve signal strength. However, this requires quantum control over the spectroscopy ion, which can be achieved by co-trapping it with a well-controlled logic ion. Using the technique of quantum logic spectroscopy, it has been shown that even hard-to-control ion species can be prepared in a pure quantum state and measured non-destructively with high precision.
I will present our progress towards full quantum control of the hydrogen molecular ion H$_{2}^{+}$ and its reaction product H$_{3}^{+}$, each co-trapped with a beryllium ion in a linear Paul trap. We have demonstrated H$_{2}^{+}$ trapping times of up to $11^{+6}_{-3}$ hours, enabled by cryogenic pumping of background H$_{2}$ that suppresses chemical reactions converting H$_{2}^{+}$ to H$_{3}^{+}$. We have achieved ground-state cooling of one of the motional modes of both H$_{2}^{+}$ and H$_{3}^{+}$, which is one of the first steps in many implementations of quantum logic spectroscopy. In addition, our cryogenic apparatus should allow for the use of buffer gas to cool the rovibration of molecular ions to their ground state.
