Measurability of the Proton Electric Dipole Moment

Sandars, P. G. H.

doi:10.1103/physrevlett.19.1396

Cited by 199 publications

(167 citation statements)

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“…However, among the ultracold heteronuclear dimers the Fermi-Fermi molecules are of special interest since they are expected to exhibit long lifetimes for the same reasons as in the homonuclear case [6]. Long-lived polar molecules open the door to the creation of a molecular Bose-Einstein condensate (BEC) [7] with anisotropic, electric dipolar interaction and show potential for precision measurements [8] and novel quantum information experiments [9]. Furthermore, the two-species Fermi-Fermi mixture may allow the realization of novel quantum phases [10,11,12] and offers the possibility to tune interactions and to conveniently apply componentselective experimental methods.…”

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confidence: 99%

Ultracold Heteronuclear Fermi-Fermi Molecules

et al. 2009

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We report on the first creation of ultracold bosonic heteronuclear molecules of two fermionic species, 6 Li and 40 K, by a magnetic field sweep across an interspecies s-wave Feshbach resonance. This allows us to associate up to 4 × 10 4 molecules with high efficiencies of up to 50%. Using direct imaging of the molecules, we measure increased lifetimes of the molecules close to resonance of more than 100 ms in the molecule-atom mixture stored in a harmonic trap.PACS numbers: 03.75. Ss, 37.10.Pq Two-component mixtures of fermionic quantum gases have attracted much interest over the past years. In these systems, long-lived, weakly bound molecules were produced made up of two atoms of the same species in different internal states [1]. The long lifetimes observed for these molecular gases are a consequence of the Pauli principle, which suppresses three-body collisions, and hence vibrational quenching, in a system of not more than two distinguishable components [2]. More recently, the interest has shifted towards ultracold heteronuclear diatomic molecules, which can have a large electric dipole moment [3]. So far, Bose-Bose [4] and Bose-Fermi [5] dimers have been produced. However, among the ultracold heteronuclear dimers the Fermi-Fermi molecules are of special interest since they are expected to exhibit long lifetimes for the same reasons as in the homonuclear case [6]. Long-lived polar molecules open the door to the creation of a molecular Bose-Einstein condensate (BEC) [7] with anisotropic, electric dipolar interaction and show potential for precision measurements [8] and novel quantum information experiments [9]. Furthermore, the two-species Fermi-Fermi mixture may allow the realization of novel quantum phases [10,11,12] and offers the possibility to tune interactions and to conveniently apply componentselective experimental methods.In this Letter, we present the first production of ultracold diatomic molecules composed of two different fermionic atomic species. We study the creation process of the molecules, their lifetime in a molecule-atom mixture and give an upper bound for their magnetic moment.We initially create an ultracold two-species FermiFermi mixture by sympathetic cooling of the fermionic species 6 Li and 40 K with an evaporatively cooled bosonic species, 87 Rb, as described previously [13,14]. During the cooling process, the three species are confined in a magnetic trap in their most strongly confined and collisional stable states 87 Rb |F = 2, m F = 2 , 40 K |9/2, 9/2 , and 6 Li |3/2, 3/2 . For the exploitation and study of Feshbach resonances (FR), the apparatus was extended by an optical dipole trap (ODT) and a setup that allows us to apply a stable homogeneous magnetic field (FB field) of up to 1 kG in the horizontal plane. The ODT is realized by two perpendicular laser beams with the two foci coinciding at the center of the magnetic trap. The first (second) beam points along the horizontal (vertical) axis and has a 1/e 2 -radius of 55 µm (50 µm). The two beams originate from a single-mode, s...

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Ultracold Heteronuclear Fermi-Fermi Molecules

et al. 2009

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“…It is known that the simultaneous violation of parity P and time reversal invariance T can be larger by several orders of magnitudes for diatomic molecules than for atoms (Sandars 1967). For molecules the enhancement is of the order of 104-105, and it is due to the narrow spacing of energy levels with the opposite parity.…”

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Calculation of the P- and T-odd spin-rotational Hamiltonian of the PbF molecule

Kozlov¹,

Fomichev²,

Dmitriev³

et al. 1987

J. Phys. B: At. Mol. Phys.

101

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Abstract. The electron wavefunctions for two states of the PbF molecule are calculated. For the ground state of the molecule, tensor components of the hyperfine interaction of the valence electron with the nuclear spin of Pb, electric and magnetic dipole moments and electron matrix elements of P-odd and P, T-odd interactions are calculated. In accordance with the calculation an effective spin-rotational Hamiltonian for the molecule is given. The Hamiltonian includes the parity-non-conserving terms and the interaction with the external fields. The spin-rotational spectrum of the PbF molecule is found to be rather complicated; this is connected with the large anisotropy of the hyperfine A tensor. The results of the present work can be used in planning future experiments on the search for P-odd and P, T-odd phenomena in molecules.

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“…A number of studies using atoms have been performed during the past few decades to extract an upper limit for the eEDM [6]. In general, for heavy polar molecules, the effective electric field experienced by an electron (E eff ) obtained from relativistic molecular calculations can be several orders of magnitude larger than that in atoms [7]. Therefore, the experimental observable (i.e., the shift in energy because of the interaction of the electric field with the eEDM) is also several orders of magnitude larger.…”

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

et al. 2014

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An accurate determination of the effective electric field (E eff ) in YbF is important, as it can be combined with the results of future experiments to give an improved new limit for the electric dipole moment of the electron. We report a relativistic coupled-cluster calculation of this quantity in which all the core electrons were excited. It surpasses the approximations made in the previous reported calculations. We obtain a value of 23.1 GV/cm for E eff in YbF with an estimated error of less than 10%. The crucial roles of the basis sets and the core excitations in our work are discussed.The electric dipole moment (EDM) of a nondegenerate system arises from violations of both the parity (P) and the time-reversal (T) symmetries [1]. T violation implies charge parity (CP) violation via CPT theorem [2]. In general, CP violation is a necessary condition for the existence of the EDMs of physical systems, and, in particular, atoms and molecules. Paramagnetic atoms and molecules are sensitive to the EDM of the electron (eEDM) [3], which is an important probe of the physics beyond the standard model [4]. The eEDM arising from CP violation could also be related to the matter-antimatter asymmetry in the universe [5]. A number of studies using atoms have been performed during the past few decades to extract an upper limit for the eEDM [6]. In general, for heavy polar molecules, the effective electric field experienced by an electron (E eff ) obtained from relativistic molecular calculations can be several orders of magnitude larger than that in atoms [7]. Therefore, the experimental observable (i.e., the shift in energy because of the interaction of the electric field with the eEDM) is also several orders of magnitude larger. Owing to the high sensitivity of the eEDM in molecules, there has been a considerable increase in interest in this field during the past decade The aim of the present work is to calculate E eff in YbF using a rigorous relativistic many-body method, which is more accurate than the methods used in the previous calculations. The method we have chosen is the four-component relativistic coupled-cluster (RCC) method, which is arguably the current gold standard for calculating the electronic structure of heavy atoms and diatomic molecules [18].The electron EDM interaction Hamiltonian in a molecule can be written as [19] Here, d e is the eEDM of an electron,  is one of the Dirac matrices, and  are the Pauli spin matrices. i is the index of summation labelling for electrons and N e is the total number of electrons. E int is the electric field acting on an electron in a molecule. The quantity that is of experimental interest in the search for the eEDM is an energy shift (E) of a particular state owing to the interaction Hamiltonian given in Eq.(1). This can be expressed as

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Measurability of the Proton Electric Dipole Moment

Cited by 199 publications

References 13 publications

Ultracold Heteronuclear Fermi-Fermi Molecules

Ultracold Heteronuclear Fermi-Fermi Molecules

Calculation of the P- and T-odd spin-rotational Hamiltonian of the PbF molecule

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

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