Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 56: Poster VII
Q 56.33: Poster
Thursday, March 14, 2024, 17:00–19:00, KG I Foyer
Artificial clock transitions with multiple trapped 40Ca+ ions as frequency references — •Kai Dietze1,2, Lennart Pelzer1, Ludwig Krinner1,2, Fabian Dawel1, Johannes Kramer1,2, and Piet O. Schmidt1,2 — 1QUEST Institute for Experimental Quantum Metrology, Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany — 2Bundesallee 100
The statistical uncertainty of trapped ion optical atomic clocks is often limited by the quantum projection noise (QPN) of the underlying quantum system. Low ion numbers, dephasing and transition broadening due to environmental noise or adjacent ions is limiting the transition linewidth and signal-to-noise ratio and therefore the achieavable statistical uncertainty. Here we focus on creating artificial quantum system with the Zeeman states of the 4 S1/2 to 5D5/2 clock transition of 40Ca+, improving the QPN compared to classical interrogation protocols.
We will present our results on creating a frequency reference using continuous dynamical decoupling, mitigating noise from magnetic field fluctuations as well as the quadrupole-shift often limiting larger ion numbers [1].
Furthermore we will present results on using GHZ entangled states between two ions as a frequency reference. These state are designed to be in a decoherence free subspace against magnetic field fluctuations, allowing close to lifetime limited coherence times. We demonstrated QPN-limited relative frequency stability for this system, reaching even below the QPN of uncorrelated atoms for intermediate timescales.
[1] Pelzer et al., arXiv:2311.13736
Keywords: trapped ions; quantum optics; optical atomic clocks