CPT Symmetry and Its Violation

Lehnert, Ralf

doi:10.3390/sym8110114

Cited by 41 publications

(51 citation statements)

References 35 publications

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“…We detect the molecules in F = 0 and F = 1 sequentially, in detectors A and B. In detector A, a resonant microwave field couples the states (N, F) = (0, 0) and (1,1 ). A probe laser together with sidebands, tuned to the the P(1) transition, is used to detect the molecules.…”

Section: State Detectionmentioning

confidence: 99%

See 1 more Smart Citation

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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Section: State Detectionmentioning

confidence: 99%

“…Any local, energy-positive, Lorentz-invariant field theory must conserve CPT, the combined symmetry of parity (P), time-reversal symmetry (T) and charge conjugation (C) [1,2]. A permanent electric dipole moment of the electron (eEDM) violates both P and T, and so requires some amount of CP violation to exist.…”

Section: Introductionmentioning

confidence: 99%

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 aim is to show how parity determines the interplay of optical and material chirality, with special regard to chirally selective interactions. The fundamental symmetries of significance to optical and electromagnetic phenomena are the parities with respect to charge, space and time inversion-operations denoted by ,  ,  and  , respectively [35][36][37]. Each of these has the cast of an Abelian group Z 2 , with eigenvalues of ±1 signifying even or odd parity, such that double operation is an identity.…”

Section: Symmetry and Parity In Electrodynamicsmentioning

confidence: 99%

Quantum formulation for nanoscale optical and material chirality: symmetry issues, space and time parity, and observables

Andrews

2018

J. Opt.

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To properly represent the interplay and coupling of optical and material chirality at the photonmolecule or photon-nanoparticle level invites a recognition of quantum facets in the fundamental aspects and mechanisms of light-matter interaction. It is therefore appropriate to cast theory in a general quantum form, one that is applicable to both linear and nonlinear optics as well as various forms of chiroptical interaction including chiral optomechanics. Such a framework, fully accounting for both radiation and matter in quantum terms, facilitates the scrutiny and identification of key issues concerning spatial and temporal parity, scale, dissipation and measurement. Furthermore it fully provides for describing the interactions of structured or twisted light beams with a vortex character, and it leads to the complete identification of symmetry conditions for materials to provide for chiral discrimination. Quantum considerations also lend a distinctive perspective to the very different senses in which other aspects of chirality are recognized in metamaterials. Duly attending to the symmetry principles governing allowed or disallowed forms of chiral discrimination supports an objective appraisal of the experimental possibilities and developing applications.

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“…The realm of optics and electrodynamics generally addresses mechanisms that fundamentally involve the positions and motions of electrical charges. Accordingly, it is the symmetry laws associated with charge, spatial position, and time that are of primary significance, that is, the operations of charge, space, and time inversion denoted by C, P, and T , respectively [11][12][13]. Each is formally represented by the Abelian group Z 2 , whose ±1 eigenvalues signify even or odd parity.…”

Section: Charge-parity-time Symmetry In Molecular Electrodynamicsmentioning

confidence: 99%

“…Each is formally represented by the Abelian group Z 2 , whose ±1 eigenvalues signify even or odd parity. All optical phenomena preserve symmetry under the product operation CP T -a proof of this universality and analysis of its implications has been authoritatively presented in a recent review by Lehnert [12], and a broad spectroscopic perspective on the topic has been given by Lazzeretti [14]. Nonetheless, considerations of charge conjugation symmetry are seldom relevant for conventional electrodynamic phenomena, as the mathematical operation C is never physically realized; clouds of negative charge always surround positively charged nuclei.…”

Section: Charge-parity-time Symmetry In Molecular Electrodynamicsmentioning

confidence: 99%

Symmetries, Conserved Properties, Tensor Representations, and Irreducible Forms in Molecular Quantum Electrodynamics

Andrews

2018

Symmetry

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In the wide realm of applications of quantum electrodynamics, a non-covariant formulation of theory is particularly well suited to describing the interactions of light with molecular matter. The robust framework upon which this formulation is built, fully accounting for the intrinsically quantum nature of both light and the molecular states, enables powerful symmetry principles to be applied. With their origins in the fundamental transformation properties of the electromagnetic field, the application of these principles can readily resolve issues concerning the validity of mechanisms, as well as facilitate the identification of conditions for widely ranging forms of linear and nonlinear optics. Considerations of temporal, structural, and tensorial symmetry offer significant additional advantages in correctly registering chiral forms of interaction. More generally, the implementation of symmetry principles can considerably simplify analysis by reducing the number of independent quantities necessary to relate to experimental results to a minimum. In this account, a variety of such principles are drawn out with reference to applications, including recent advances. Connections are established with parity, duality, angular momentum, continuity equations, conservation laws, chirality, and spectroscopic selection rules. Particular attention is paid to the optical interactions of molecules as they are commonly studied, in fluids and randomly organised media.

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CPT Symmetry and Its Violation

Cited by 41 publications

References 35 publications

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

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

Quantum formulation for nanoscale optical and material chirality: symmetry issues, space and time parity, and observables

Symmetries, Conserved Properties, Tensor Representations, and Irreducible Forms in Molecular Quantum Electrodynamics

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