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arXiv · 2605.16585

On the potential for high-accuracy spectroscopy of $\mathrm{H}_2^+$ and $\overline{\mathrm{H}}_2^-$ in Penning traps for a test of CPT invariance

Stephan Schiller·Juan M. Cornejo·Nikita Poljakov·Christian Ospelkaus·Stefan Ulmer·Dimitar Bakalov
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Abstract

The comparison of vibrational transition frequencies of $\mathrm{H}_2^+$ and $\overline{\mathrm{H}}_2^-$ offers a new opportunity to test CPT invariance. Myers [Phys. Rev. A 98, 010101(R) (2018)] proposed performing laser spectroscopy in a Penning trap (PT) with non-destructive read-out. Here, we provide an extensive analysis of this proposal, introduce novel aspects, and discuss its implementation in PTs that incorporate either the continuous Stern-Gerlach effect or quantum-logic spectroscopy. We derive estimates for the achievable accuracy of the test. We find that a comparison of the vibrational frequencies at a fractional level of $1\times10^{-17}$ is a realistic prospect, using technology that is mostly already available. We also analyze complementary CPT invariance tests, namely those of the g-factor of the bound electron/positron via electron-spin-resonance spectroscopy and of the magnetic moment of the proton/antiproton via radiofrequency spectroscopy.

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Stephan Schiller, Juan M. Cornejo, Nikita Poljakov, Christian Ospelkaus, Stefan Ulmer, Dimitar Bakalov. 2026-05-15. On the potential for high-accuracy spectroscopy of $\mathrm{H}_2^+$ and $\overline{\mathrm{H}}_2^-$ in Penning traps for a test of CPT invariance. https://arxiv.org/abs/2605.16585

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