Speaker
Description
In our cryogenic multi-Penning trap experiment, we focus on testing CPT symmetry [1] by performing high-precision measurements of the $g$-factor of protons [2] and antiprotons [3]. We aim to reach precision beyond the parts-per-billion level, by using quantum logic spectroscopy [4,5] that employs a single, laser-cooled $^{9}$Be$^{+}$ ion. With that ion sympathetic cooling and spin-state detection of the (anti-)proton can be archived by coupling the particle motion via Coulomb interaction in a double-well potential.
We aim to employ a micro fabricated Penning trap with a double-well potential and an inner diameter of 800 µm and a tunable offset of the trapping potential. A small separation between the wells together with tailored curvature strengthen Coulomb coupling and shorten the exchange time. However this is only achieved if the geometry is aligned with high precision. The compact diameter provides strong, stable axial confinement at modest voltages, enabling deep, precisely-controlled wells. Simulations support a two-stage protocol for coupling: an initial frequency sweep followed by static near-harmonic coupling, that achieves efficient energy exchange under practically achievable stability constraints [6], motivating a small, highly precise trap for sympathetic cooling and quantum-logic readout of single (anti-)protons.
We present the fabrication of such a micro-coupling trap. We design and fabricate this precise, small‑diameter trap section with thin, segmented electrodes using microfabrication techniques. The three‑dimensional electrode geometry is structured by selective laser‑induced etching (SLE) [7] on fused silica wafers, followed by physical vapor deposition (PVD) of an seed layer stack and subsequent electroplating to obtain low‑resistance, cryo‑compatible electrodes.
[1] R. Lehnert, Symmetry 8 (2016) [2] G. Schneider et al., Science 358 (2017) [3] C. Smorra et al., Nature 550 (2017) [4] D. J. Heinzen and D. J. Wineland, Phys. Rev. A, 42 (1990) [5] P. O. Schmidt et al., Science 309 (2005) [6] N. Poljakov et al., arXiv:2602.22826 (2026) [7] A. Marcinkevicius et al., Opt. Lett. 26 (2001)
| Academic level | Research assistant |
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