Application of relativistic coupled-cluster theory to the effective electric field in YbF

Abe, Masahide; Gopakumar, Geetha; Hada, Masahiko; Das, B. P.; Tatewaki, Hiroshi; Mukherjee, Debashis

doi:10.1103/physreva.90.022501

Cited by 70 publications

(98 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find very similar behaviour in YbF [33], as did Abe et al in Ref. [68]. This instability, in particular for the v3z basis, can be attributed to the multireference character of the ground state configurations of these systems, which we were able to diagnose via the large T 1 values.…”

Section: Treatment Of Electron Correlationsupporting

confidence: 89%

Enhancement factor for the electric dipole moment of the electron in the BaOH and YbOH molecules

et al. 2019

View full text Add to dashboard Cite

Polyatomic polar molecules are promising systems for future experiments that search for violation of time-reversal and parity symmetries due to their advantageous electronic and vibrational structure, which allows laser cooling, full polarisation of the molecule, and reduction of systematic effects [I. Kozyryev and N.R. Hutzler, Phys, Rev. Lett. 119, 133002 (2017)]. In this work we investigate the enhancement factor of the electric dipole moment of the electron (E eff ) in the triatomic monohydroxide molecules BaOH and YbOH within the high-accuracy relativistic coupled cluster method. The recommended E eff values of the two systems are 6.65 ± 0.15 GV/cm and 23.4 ± 1.0 GV/cm, respectively. We compare our results with similar calculations for the isoelectronic diatomic molecules BaF and YbF, which are currently used in experimental search for P, T -odd effects in molecules. The E eff values prove to be very close, within about 1.5 % difference in magnitude between the diatomic and the triatomic compounds. Thus, BaOH and YbOH have a similar enhancement of the electron electric dipole moment, while benefiting from experimental advantages, and can serve as excellent candidates for next-generation experiments.

show abstract

Section: Treatment Of Electron Correlationsupporting

confidence: 89%

Enhancement factor for the electric dipole moment of the electron in the BaOH and YbOH molecules

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The H state of ThO has one of the largest calculated values of  » 77.6 eff GV cm −1 [29,30]. We note that the value of  eff in our experiment with ThO is more than 5 times larger than that attained in experiments using YbF, which set the previous eEDM limit [55][56][57], and over 1000 times larger than that in experiments using Tl atoms [42].…”

Section: Tho Moleculecontrasting

confidence: 49%

Methods, analysis, and the treatment of systematic errors for the electron electric dipole moment search in thorium monoxide

et al. 2017

View full text Add to dashboard Cite

We recently set a new limit on the electric dipole moment of the electron (eEDM) (J Baron et al and ACME collaboration 2014 Science 343 269-272), which represented an order-of-magnitude improvement on the previous limit and placed more stringent constraints on many charge-parityviolating extensions to the standard model. In this paper we discuss the measurement in detail. The experimental method and associated apparatus are described, together with the techniques used to isolate the eEDM signal. In particular, we detail the way experimental switches were used to suppress effects that can mimic the signal of interest. The methods used to search for systematic errors, and models explaining observed systematic errors, are also described. We briefly discuss possible improvements to the experiment. 9 Note that the limit we report here uses an updated value for  = 78 eff GV cm −1 which is obtained by averaging the results from [29, 30]. 10 A detailed discussion of the sign convention for this Hamiltonian term is provided in section appendix A.3 1 states have very small magnetic moments [58] since the d 3 2 orbital valence electron serves to nearly cancel the magnetic moment of the s 1 2 orbital. The actual magnetic moment of H deviates from zero primarily because of mixing with other states [59]. We express ThO molecule states using the basis Wñ |Y J M , , , , where Y is the electronic state, J is the total angular momentum, M is the projection of J onto the laboratoryẑ-axis, and Ω 1 (V cm −1 ) −1 [67]; this permits full (>99%) polarisation of the state in small applied electric fields,   10 V cm −1 , allowing us to take full advantage of the huge  eff in ThO. The Ω-doublet structure is also useful in rejecting systematic errors since it allows for spectroscopic reversal of  µ -n eff by addressing different  states without reversing the applied electric field [68]. This is discussed in greater detail in section 5.4.The H state in ThO is metastable with a lifetime »1.8 ms [69], limiting our measurement time to t » 1 ms. We note that this is comparable to previous beam-based eEDM measurements where the atomic/molecular states used had significantly longer lifetimes [20,69,70]. 1 (V cm −1 ) −1 (black arrow/lines) is the expectation value of the molecular electric dipole moment in these states [60]. Additionally, a magnetic field   causes a Zeeman shift  m »-Mg z 1 B , with m p » -ǵ 2 6kHz 1 B G −1 (red arrow/lines) [59, 64]. A nonzero eEDM would result in an additional energy shift   »-M d e eff (blue arrow/lines) where  = -1 (+1) when the applied  field is (is not) reversed. The orientation of   eff (green arrows), the spin of the electron in the σ orbital (black arrow next to molecule), the external electric field  , and the external magnetic field   are shown relative to the laboratoryẑ direction which is oriented upwards on the page. Diagram not to scale. 11 Throughout the paper, we give numerical values of energies (with  = 1) in terms of angular frequencies by using the notation p´f 2 , where f ...

show abstract

“…The above expression casts the eEDM Hamiltonian in terms of one-electron operators, which makes it convenient for computations. Further details of the derivation of this form can be found in [9].To obtain the molecular wavefunction |ψ , we use a relativistic coupled cluster (RCC) method [10,11]. The coupled cluster wavefunction can be written as…”

mentioning

confidence: 99%

Mercury Monohalides: Suitability for Electron Electric Dipole Moment Searches

et al. 2015

Self Cite

View full text Add to dashboard Cite

Heavy polar diatomic molecules are the primary tools for searching for the T -violating permanent electric dipole moment of the electron (eEDM). Valence electrons in some molecules experience extremely large effective electric fields due to relativistic interactions. These large effective electric fields are crucial to the success of polar-molecule-based eEDM search experiments. Here we report on the results of relativistic ab initio calculations of the effective electric fields in a series of molecules that are highly sensitive to an eEDM, the mercury monohalides (HgF, HgCl, HgBr,and HgI). We study the influence of the halide anions on E eff , and identify HgBr and HgI as interesting candidates for future electric dipole moment search experiments.Violation of time-reversal (T ) symmetry is an essential ingredient to explain the matter-antimatter asymmetry of the universe [1,2]. As Standard Model sources of T -violation are inadequate to explain the observed asymmetry, it is imperative to look beyond it. The strongest limits on T -violation arising from new particles and interactions outside the Standard Model are set by searches for the permanent electric dipole moments of fundamental particles [3,4], like that of the electron (d e ). A strong constraint on the electron's electric dipole moment (eEDM),−28 e cm, has been set by the experiment with ThO molecules [5], and improvements of a few orders of magnitude are forecast in the near future [5,6]. The eEDM experiments take advantage of the large effective electric field (often > ∼ 10 10 V/cm) experienced by an electron in a polarized heavy polar molecule, which leads to a measurable energy shift, ∆E ∝ d e E eff . The effective electric field, E eff , arises from the relativistic interactions of the eEDM with the electric fields of all the other charged particles in the molecule. This effect, whereby molecules polarized by ∼ kV/cm laboratory fields cause > 10 GV/cm to be applied to a valence electron, is the reason for the high precision achievable in molecule-based eEDM experiments.The value of E eff for a molecule has to be obtained from relativistic many-body calculations in order to convert experimentally measured frequency shifts into eEDM values. A common heuristic that is used to estimate E eff in molecules, motivated from eEDM enhancement scaling in atoms, is that E eff ∝ Z 3 + , where Z + is the charge of the (usually heavier) cationic atom's nucleus. But molecules are not atoms. This heuristic ignores the anions which can play an important role. An improved understanding of the mechanisms leading to E eff in relativistic polar molecules will lead to better choices of candidate molecules for future eEDM experiments.In this work, we focus on the E eff for a class of heavy polar molecules, the mercury monohalides, in order to test their suitability for eEDM searches. The properties of these systems can be evaluated fairly accurately, as they have a single valence electron. The fact that they are sensitive to eEDMs in their ground electronic states (unlik...

show abstract

Application of relativistic coupled-cluster theory to the effective electric field in YbF

Cited by 70 publications

References 37 publications

Enhancement factor for the electric dipole moment of the electron in the BaOH and YbOH molecules

Enhancement factor for the electric dipole moment of the electron in the BaOH and YbOH molecules

Methods, analysis, and the treatment of systematic errors for the electron electric dipole moment search in thorium monoxide

Mercury Monohalides: Suitability for Electron Electric Dipole Moment Searches

Contact Info

Product

Resources

About