Improved limit on the electric dipole moment of the electron

“…With this sensitivity, we would expect a statistical uncertainty at the 10 −29 e cm level in a measurement consisting of 100 days of eEDM data. This is at a similar level of sensitivity to the current leading eEDM experiments [13,14], but with a different molecular species and experimental setup. Further upgrades to the present apparatus are also possible.…”

Section: Discussionmentioning

confidence: 61%

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confidence: 85%

“…This experiment benefited from the long coherence times available in a molecular ion trap, but was limited by the relatively low number of ions trapped. In 2018, the ACME collaboration improved on their limit, reaching |d e | < 1.1 × 10 −29 e cm [14]. This last result constrains any new physics arising from T-violating effects to energy scales above 3 TeV [14].Many new ideas are now emerging on how to improve measurement sensitivity even further.…”

mentioning

confidence: 97%

“…In 2018, the ACME collaboration improved on their limit, reaching |d e | < 1.1 × 10 −29 e cm [14]. This last result constrains any new physics arising from T-violating effects to energy scales above 3 TeV [14].Many new ideas are now emerging on how to improve measurement sensitivity even further. In present experiments, the total uncertainty is typically dominated by the statistical uncertainty, so methods to improve statistical sensitivity are needed.…”

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confidence: 97%

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New techniques for a measurement of the electron’s electric dipole moment

Devlin

Rabey

et al. 2020

New J. Phys.

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The electric dipole moment of the electron (eEDM) can be measured with high precision using heavy polar molecules. In this paper, we report on a series of new techniques that have improved the statistical sensitivity of the YbF eEDM experiment. We increase the number of molecules participating in the experiment by an order of magnitude using a carefully designed optical pumping scheme. We also increase the detection efficiency of these molecules by another order of magnitude using an optical cycling scheme. In addition, we show how to destabilise dark states and reduce backgrounds that otherwise limit the efficiency of these techniques. Together, these improvements allow us to demonstrate a statistical sensitivity of 1.8 × 10 −28 e cm after one day of measurement, which is 1.2 times the shot-noise limit. The techniques presented here are applicable to other high-precision measurements using molecules. © 2020 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische GesellschaftNew J. Phys. 22 (2020) 053031 C J Ho et alfactors of E eff /E ext = 120 and −585 respectively 4 . The linear dependence of E eff on E ext indicates that the atoms are only weakly polarised in the external electric field. In polar molecules, the interaction energy is larger because it is easier to polarise these molecules in an electric field. It is more appropriate to write E eff = ηE eff,max for molecules, where η is the degree of polarisation of the molecule, and E eff,max is the maximum effective field seen by the electron when the molecule is fully polarised, η = 1. The latter is typically in the range 10 GV cm −1 to 100 GV cm −1 , which is much larger than electric fields that can be applied in the laboratory.In 2011, the precision of atomic measurements was surpassed in an experiment using YbF, setting a new upper limit 5 of |d e | < 1.06 × 10 −27 e cm [10]. The enhancement of YbF was E eff ≈ −14.5 GV cm −1 . Crucially, a systematic effect which is large for atoms-the Zeeman interaction with the motional magnetic field mimicking the EDM interaction-is highly suppressed in molecules due to their strong tensor polarisability [11]. In 2014, the ACME collaboration pushed the limit down to |d e | < 8.7 × 10 −29 e cm using a beam of ThO molecules in an Ω-doublet state [12]. Molecules in this state are fully polarised in a small applied electric field, giving E eff = E eff,max ≈ 84 GV cm −1 . The Ω-doublet can also be used conveniently for internal co-magnetometry. In 2017, a measurement using trapped HfF + molecular ions (E eff ≈ 23 GV cm −1 ) reported the limit |d e | < 1.3 × 10 −28 e cm [13]. This experiment benefited from the long coherence times available in a molecular ion trap, but was limited by the relatively low number of ions trapped. In 2018, the ACME collaboration improved on their limit, reaching |d e | < 1.1 × 10 −29 e cm [14]. This last result constrains any new physics arising from T-violating effects to energy scales above 3 TeV [14].Many new ideas are now emerging on ho...

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Molecular Engineering Enables Hydrogel Electrolyte with Ionic Hopping Migration and Self‐Healability toward Dendrite‐Free Zinc‐Metal Anodes

Zhu,

Luo,

Zhang

et al. 2024

Advanced Materials

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Hydrogel electrolytes (HEs), characterized by intrinsic safety, mechanical stability, and biocompatibility, can promote the development of flexible aqueous zinc‐ion batteries (FAZIBs). However, current FAZIB technology is severely restricted by the uncontrollable dendrite growth arising from undesirable reactions between the HEs with sluggish ionic conductivity and Zn metal. To overcome this challenge, this work proposes a molecular engineering strategy, which involves the introduction of oxygen‐rich poly(urea‐urethane) (OR‐PUU) into polyacrylamide (PAM)‐based HEs. The OR‐PUU/PAM HEs facilitate rapid ion transfer through their ionic hopping migration mechanism, resulting in uniform and orderly Zn2+ deposition. The abundant polar groups on the OR‐PUU molecules in OR‐PUU/PAM HEs break the inherent H‐bond network, tune the solvation structure of hydrated Zn2+, and inhibit the occurrence of side reactions. Moreover, the interaction of hierarchical H‐bonds in the OR‐PUU/PAM HEs endows them with self‐healability, enabling in‐situ repair of cracks induced by plating/stripping. Consequently, Zn symmetric cells incorporating the novel OR‐PUU/PAM HEs exhibit a long cycling life of 2000 h. The resulting Zn–MnO2 battery displays a low capacity decay rate of 0.009% over 2000 cycles at 2000 mA g−1. Overall, this work provides valuable insights to facilitate the realization of dendrite‐free Zn‐metal anodes through the molecular engineering of HEs.This article is protected by copyright. All rights reserved

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Improved limit on the electric dipole moment of the electron

Cited by 832 publications

References 46 publications

The metastable Q ³Δ₂ state of ThO: a new resource for the ACME electron EDM search

The metastable Q ³Δ₂ state of ThO: a new resource for the ACME electron EDM search

New techniques for a measurement of the electron’s electric dipole moment

Molecular Engineering Enables Hydrogel Electrolyte with Ionic Hopping Migration and Self‐Healability toward Dendrite‐Free Zinc‐Metal Anodes

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Improved limit on the electric dipole moment of the electron

Cited by 832 publications

References 46 publications

The metastable Q 3Δ2 state of ThO: a new resource for the ACME electron EDM search

The metastable Q 3Δ2 state of ThO: a new resource for the ACME electron EDM search

New techniques for a measurement of the electron’s electric dipole moment

Molecular Engineering Enables Hydrogel Electrolyte with Ionic Hopping Migration and Self‐Healability toward Dendrite‐Free Zinc‐Metal Anodes

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Product

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The metastable Q ³Δ₂ state of ThO: a new resource for the ACME electron EDM search

The metastable Q ³Δ₂ state of ThO: a new resource for the ACME electron EDM search