Observation of mHz-level cooperative Lamb shifts in an optical atomic clock
Data files
Sep 12, 2023 version files 3.83 GB
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cls.h5
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make_figures.py
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README.md
Abstract
We report on the direct observation of resonant electric dipole-dipole interactions in a cubic array of atoms in the many-excitation limit. The interactions, mediated by single-atom couplings to the shared electromagnetic vacuum, are shown to produce spatially-dependent cooperative Lamb shifts when spectroscopically interrogating the mHz-wide optical clock transition in strontium-87. We show that the ensemble-averaged shifts can be suppressed below the level of evaluated systematic uncertainties for state-of-the-art optical atomic clocks. Additionally, we demonstrate that excitation of the atomic dipoles near a Bragg angle can enhance these effects by nearly an order of magnitude compared to non-resonant geometries. Given the remarkable precision of frequency measurements and the high accuracy of the modeled response, our work demonstrates that such a clock is a novel platform for studies of the quantum many-body physics of spins with long-range interactions mediated by propagating photons.
README: Observation of mHz-level cooperative Lamb shifts in an optical atomic clock
https://doi.org/10.5061/dryad.wpzgmsbtj
The python script "make_figures.py" produces the plots in Figs. 2-4, S1-S3 given the images and control parameters contained in "cls.h5"
Description of the data and file structure
The data in "cls.h5" is saved in HDF5 format and contains the following datasets
- "timestamp_": array of timestamps corresponding to the (UNIX) time at which the corresponding experimental shot began.
- "runpath_": unique strings distinguishing runs, between which realignment/calibration procedures were performed.
- "φ_": array specifying pulse phases sin(φ_out)
- "Z_": array specifying initial pulse area 4 sqrt(2) cos(θ_in)
- "q_": array specifying probed transition
- "ψ_": array specifying angle of incidence
- "counts_g_": array of ground state images
- "counts_e_": array of excited state images
Code/Software
Running the python script "make_figures.py" requires Python 3.11+ and the following third-party libraries: allantools, h5py, matplotlib, numpy, scipy