199Hg Atoms Research Articles

Contribution of the Weinberg-type operator to atomic and nuclear electric dipole moments

The contribution of the CP violating three-gluon Weinberg operator, frac{1}{3!}w{f}^{abc}{epsilon}^{nu rho alpha beta}{G}_{mu nu}^a{G}_{alpha beta}^b{G}_{rho}^{cmu} , to the atomic and nuclear EDMs is estimated using QCD sum rules. After calculating the transition matrix element between the pion and the vacuum through the Weinberg operator, we obtain the long-range CP-odd nuclear force by determining the isovector CP-odd pion-nucleon vertex, using chiral perturbation theory at NLO. The EDMs of 199Hg, 129Xe, and 225Ra atoms, as well as those of 2H and 3He nuclei are finally given including comprehensive uncertainty analysis. While the leading contribution of the 199Hg EDM is given by the intrinsic nucleon EDM, that of 129Xe atom may be dominated by the one-pion exchange CP-odd nuclear force generated by the Weinberg operator. From current experimental data of the 199Hg atomic EDM, we obtain an upper limit on the Weinberg operator magnitude of |w| < 4 × 10−10GeV−2 if we assume that it is the only source of CP violation at the scale μ = 1 TeV.

Reappraisal of P, T-odd parameters from the improved calculation of electric dipole moment of 225Ra atom

By employing the recently developed relativistic normal coupled-cluster theory, we obtained the electric dipole moment (EDM) of 225Ra due to nuclear Schiff moment (NSM) and tensor–pseudotensor (T–PT) electron–nucleus (e–N) interaction as −6.3(5) × 10−17 S |e| cm/(|e| fm3) and −13(1) × 10−20 CT⟨σN⟩ |e| cm, respectively, for the NSM S, T–PT coupling coefficient CT and nuclear Pauli spinor σN. This is corroborated by analyzing the dipole polarizability value of 225Ra, which is obtained as 257(8) . Our EDM results, in combination with the measurement (2015 Phys. Rev. Lett. 114 233002), are about 8% and 28% improvements over the limits that were reported using the relativistic coupled-cluster theory for the NSM and T–PT e–N coupling coefficient, respectively. Further combining with the nuclear calculations, we infer limits on the EDM of neutron dn < 1.15 × 10−23 |e| cm, the EDM of proton dp < 1.1 × 10−22 |e| cm, the quantum chromodynamics parameter and the combined up- and down-quark chromo-EDMs . Though these bounds are not competitive at present with the current-best limits acquired from 199Hg atom, they can be bettered when the measurement of EDM in 225Ra improves by four orders.

Observation of the 1S0–3P0 optical clock transition in cold 199Hg atoms

We report on the observation of the highly forbidden 1S0–3P0 optical clock transition in laser-cooled 199Hg atoms. More than 95% depletion of cold 199Hg atoms is detected in the magneto-optical trap. Using the free-of-field detection method, the AC Stark shift from the cooling laser is removed from the in-field spectroscopy. At low-power clock laser pumping, the linewidth of the clock spectroscopy is approximately 450 kHz (full width at half-maximum), which corresponds to a Doppler broadening at the atom temperature of 60 μK. We determine the 1S0–3P0 transition frequency to be 1,128,575,290.819(14) MHz by referencing with a hydrogen maser and measuring with a fiber optical frequency comb. Moreover, a weak Doppler-free signal is observed.

A Single Folded Beam Magneto-Optical Trap System for Neutral Mercury Atoms**Supported by the National Natural Science Foundation of China under Grant No 91436105, the National Basic Research Program of China under Grant No 2011CB921504, and the Research Project of Shanghai Science and Technology Commission under Grant No 09DJ1400700.

Mercury is a promising candidate for the optical lattice clock, due to its low sensitivity to the blackbody radiation. We develop a single folded beam magneto-optical trap for the neutral mercury optical lattice clock, with a 253.7nm frequency quadrupled laser. Up to 1.7 × 106 (202Hg) or 1.5 × 106 (199Hg) atoms can be captured, and the atom temperature is lowered to 170 μK (202Hg) or 50 μK (199Hg). The cold atom signals of all six rich abundant isotopes are observed in this system.

Measurement of a false electric dipole moment signal from 199Hg atoms exposed to an inhomogeneous magnetic field

We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for $^{199}{\rm Hg}$ atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the motional magnetic field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving. We have used a neutron magnetic resonance EDM spectrometer, featuring a mercury co-magnetometer and an array of external cesium magnetometers, to measure the shift as a function of the applied magnetic field gradient. Our results are in good agreement with theoretical expectations.

Dark forces and atomic electric dipole moments

Postulating the existence of a fnite-mass mediator of T,P-odd coupling between atomic electrons and nucleons we consider its effect on permanent electric dipole moment (EDM) of diamagnetic atoms. We present both numerical and analytical analysis for such mediator-induced EDMs and compare it with EDM results for the conventional contact interaction. Based on this analysis we derive limits on coupling strengths and carrier masses from experimental limits on EDM of 199Hg atom.

A measurement of the neutron to 199Hg magnetic moment ratio

The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result γn/γHg=3.8424574(30).

Limits on local Lorentz invariance in mercury and cesium

We report new bounds on Local Lorentz Invariance (LLI) violation in Cs and Hg. The limits are obtained through the observation of the the spin- precession frequencies of 199Hg and 133Cs atoms in their ground states as a function of the orientation of an applied magnetic field with respect to the fixed stars. We measure the amplitudes of the dipole couplings to a preferred direction in the equatorial plane to be 19(11) nHz for Hg and 9(5) microHz for Cs. The upper bounds established here improve upon previous bounds by about a factor of four. The improvement is primarily due to mounting the apparatus on a rotating table. New bounds are established on several terms in the standard model extension including the first bounds on the spin-couplings of the neutron and proton to the z direction, <7e-30 GeV and <7e-29 GeV, respectively.

Neutral Atom Frequency Reference in the Deep Ultraviolet withFractional Uncertainty=5.7×10−15

We present an assessment of the (6s2) (1)S0 ↔ (6s6p)(3)P0 clock transition frequency in 199Hg with an uncertainty reduction of nearly 3 orders of magnitude and demonstrate an atomic quality factor Q of ∼10(14). The 199Hg atoms are confined in a vertical lattice trap with light at the newly determined magic wavelength of 362.5697±0.0011 nm and at a lattice depth of 20E(R). The atoms are loaded from a single-stage magneto-optical trap with cooling light at 253.7 nm. The high Q factor is obtained with an 80 ms Rabi pulse at 265.6 nm. We find the frequency of the clock transition to be 1,128,575,290,808,162.0±6.4(syst)±0.3(stat) Hz (i.e., with fractional uncertainty=5.7×10(-15)). Neither an atom number nor second order Zeeman dependence has yet been detected. Only three laser wavelengths are used for the cooling, lattice trapping, probing, and detection.

Molecules in the cold environment of a supersonic free-jet beam: from spectroscopy of neutral–neutral interactions to a test of Bell's inequality

The supersonic free-jet expansion technique has been used in different fields of research in physics, physical chemistry and chemistry to study vibrational and rotational molecular structures in ground and excited electronic energy states as well as in cold chemistry to study chemical reactions in a unique environment. The supersonic beam technique, as a widely used method in laser spectroscopy of molecules, exploits a source of monokinetic, rotationally and vibrationally cold molecules, that are very weakly bound in their ground electronic states (van der Waals molecules). In experiments at Jagiellonian University the supersonic free-jet beam serves as a source of ground-state van der Waals objects in studies of neutral–neutral interactions between group 12 metal (M = Zn, Cd, Hg) and noble gas (NG) atoms. Recently, the method has been applied as a source of entangled 199Hg atom pairs in order to test Bell's inequality in an experiment at Texas A&M University.

Quark dipole operators in extended technicolor models

We study diagonal and transition quark dipole operators in a class of extended technicolor (ETC) models, taking account of the multiscale nature of the ETC gauge symmetry breaking and of the mixing among ETC interaction eigenstates. Because of this mixing, terms involving the lowest ETC scale can play an important role in dipole operators, and we focus on these terms. We derive from experiment new correlated constraints on the quark mixing angles and phases. Our bounds yield information on mixing angles individually in the up- and down-sectors, for both left- and right-handed quark fields and thus constrain even quark mixing parameters that do not enter in the CKM matrix. With phases of order unity, we conclude that these mixing angles are small, constraining future ETC model building, but plausibly in the range suggested by the size of the CKM elements. These values still allow substantial deviations from the standard model predictions, in particular for several CP violating quantities, including the asymmetries in b→sγ and Bd→ϕKS, Re(ε′/ε), and the electric dipole moments of the neutron and the 199Hg atom.

New constraint on squark flavor mixing from 199Hg electric dipole moment

A new constraint is obtained on the CP-violating flavor mixing between the left-handed top scalar quark (t̃L) and charm scalar quark (c̃L), by considering a chargino loop contribution to chromo-electric dipole moment of strange quark, which is limited by the electric dipole moment of the 199Hg atom. It is found that the flavor mixing should be suppressed to the level of O(0.1) for the CP phase of order unity, when tanβ is relatively large and sparticle masses lie in a few hundred GeV range. Although it is much stronger than the known constraint from the chargino loop contribution to b→sγ, the moderate constraint we obtain here is argued to leave room for sizable supersymmetric contribution to the CP asymmetry in Bd0→φKs.

B→φKs versus electric dipole moment of 199Hg atom in supersymmetric models with right-handed squark mixing

The correlation between the CP asymmetry in B→φKs (SφKs) and the chromoelectric dipole moment (CEDM) of strange quark (dsC), which is constrained by the electric dipole moment (EDM) of 199Hg, is studied in the supersymmetric (SUSY) models with the right-handed squark mixing. It is known that, if the right-handed bottom and strange squarks have a CP-violating mixing, such as in the SUSY SU(5) GUT with right-handed neutrinos, the induced gluon penguin diagram may give a sizable contribution to SφKs. However, when the left-handed bottom and strange squarks also have a mixing, the conspiracy of the left and right-handed squarks may lead to a sizable dsC, which is enhanced by mb/ms. While the estimate for the EDM of 199Hg, induced by dCs, might have large uncertainties due to the hadron and nuclear dynamics, the current bound implies the gluon penguin contribution by the right-handed squarks to SφKs should be suppressed and the deviation of SφKs from the Standard Model may not be so large. Also, we discuss the constraint from the EDM of 199Hg in the SUSY SU(5) GUT with the right-handed neutrinos.

CP phases, electric dipole moments, and a linear collider

We reexamine large CP violating phases in the Minimal Supersymmetric Standard Model. In a detailed scan over parameter space we find solutions which satisfy the current experimental limits on the Electric Dipole Moments of the electron, neutron and 199Hg atom. We then consider the measurement of CP violating phases at a future Linear Collider. We find that measurements of chargino and neutralino masses and production cross-sections allow for a determination of φ 1 to a typical precision of π/30, while the EDM constraints require that θ μ be too small to be measured.

New limit on the permanent electric dipole moment of 199Hg.

We present the first results of a new search for a permanent electric dipole moment of the 199Hg atom using a UV laser. Our measurements give d(199Hg) = -(1.06+/-0.49+/-0.40)x10(-28)e cm. We interpret the result as an upper limit absolute value [d(199Hg)]<2.1x10(-28)e cm (95% C.L.), which sets new constraints on theta bar;(QCD), chromo-EDMs of the quarks, and CP violation in supersymmetric models.

MSSM predictions for the electric dipole moment of the 199Hg atom

The Minimal Supersymmetric Standard Model can possess several CP-violating phases beyond the conventional Cabibo-Kobayashi-Maskawa phase. We calculate the contribution of these phases to T-violating nuclear forces. These forces induce a Schiff moment in the $^{199}$Hg nucleus, which is strongly limited by experiments aimed at the detection of the electric dipole moment of the mercury atom. The result for $d_{Hg}$ is found to be very sensitive to the CP-violating phases of the MSSM and the calculation carries far fewer QCD uncertainties than the corresponding calculation of the neutron EDM. In certain regions of the MSSM parameter space, the limit from the mercury EDM is stronger than previous constraints based on either the neutron or electron EDMs. We present combined constraints from the mercury and electron EDMs to limit both CP-violating phases of the MSSM. We also present limits in mSUGRA models with unified gaugino and scalar masses at the GUT scale.

The Einstein–Podolsky–Rosen debate: on the way to a final answer

The status of our experimental realization of Bohm’s spin-1/2 particle version of the Einstein-Podolsky-Rosen gedankenexperiment is discussed. This new experiment provides a definitive test of the, as yet, untested strong Bell inequalities. It closes the two widely recognized loopholes associated with previous experiments, and has the interesting new feature that the entangled state exists for milliseconds rather than nanoseconds. The spin one-half particles are two 199Hg atoms in an entangled nuclear spin state with total nuclear spin zero. Measurement of the nuclear spin correlation is achieved by detection of each atom using a spin state selective two photon excitation-ionization scheme.

Bell inequalities and two experimental tests with mercury

Most experimental tests of Bell inequalities have involved measurements of correlations between two photons. One of the first definitive experiments involved the linear polarization correlation between two photons in an atomic cascade of 200Hg. That experiment is discussed in depth in this paper. The form of the initial state density matrix was a critical part of that experiment; and the experimental and theoretical determination of the density matrix, including finite solid-angle effects is discussed. However, all Bell inequality experiments to date have two widely recognized loopholes, detector efficiency and locality. This paper concludes with a very brief description of an experiment that will close both of these loopholes. In contrast to existing experiments with photons, this new test involves spin correlations between the nuclei of two 199Hg atoms; it is an exact experimental realization of Bohm's version of the Einstein-Podolsky-Rosen gedankenexperiment.

Synthesis, Raman and NMR spectroscopy of the trimetallic complexes [IrCl(SnCl 3)(HgCl)(CO)(PR 3) 2

Synthesis, Raman and NMR studies are presented for the new octahedral trimetallic complexes with composition [IrCl(SnCl 3)(HgCl)(CO)(PR 3) 2], R = p-XC 6H 4; X = H, CH 3O, F, Cl. Only the isomer containing the Cl 3SnIrHgCl fragment and trans phosphine ligands is observed. Force constants for the IrSn and IrHg bonds as well as 31P, 119Sn and 199Hg NMR data are reported. The presence of a spin-spin coupling constant of more than 40,000 Hz between the 199Hg and 119Sn atoms is shown to originate from a two-bond and not a one-bond interaction.

Study of orientation transfer by collisions of the second kind between 198Hg and 199Hg atoms

A double resonance experiment is used to detect the collisional transfer of orientation from an optically oriented 198Hg (6 3P 1) atom to the hyperfine levels (6 3P 1; F = 1 2 , F = 3 2 ) of a 199Hg atom. The reaction of transfer is assumed to be 198Hg (6 3P 1) + 199Hg (6 1S 0) → 198Hg (6 1S 0) + 199Hg (6 3P 1). The theory of such a process is summarized, the experimental set-up described and the double resonance signals compared with those predicted by the theory.