Abstract
Electric dipole selection rules require that E1 transitions must connect states of opposite parity (u ↔ g and g ↔ u) and ΔJ = 0, ±1. However, these rules can be broken in the presence of magnetic fields, which can cause mixing among nearby levels and cause previously “good” quantum numbers to become “bad.”
We provide a simple framework for understanding this phenomenon based on perturbation theory, and discuss its experimental implications. This framework implies that previously forbidden transitions can become allowed in the presence of small magnetic fields. Specifically, the strengths of “singly forbidden” transitions should increase quadratically with magnetic field, while the strengths of “doubly forbidden” transitions should increase quartically.
We test these predictions by accurately measuring relative transition strengths for a series of “forbidden” transitions in 88Sr2. This study required developing state-of-the-art techniques for the quantitative measurement of transition strengths, which is surprisingly poorly described in the literature. We demonstrate a series of interesting effects, including observation of mixed quantization for transitions between states defined by orthogonal quantum axes and millionfold enhancement of the strengths of “forbidden” ΔJ = 2, 3 transitions with the application of magnetic fields of only a few tens of Gauss. We also discuss the relative strengths and weaknesses of three different techniques for quantitatively determining transition strengths.
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Einstein, A.: Strahlungs-emission und absorption nach der quantentheorie. Dtsch. Phys. Ges. 18, 318–323 (1916)
Foot, C.: Atomic Physics. Oxford Master Series in Atomic, Optical, and Laser Physics. Oxford University Press, Oxford (2005)
Hilborn, R.: Einstein coefficients, cross sections, f values, dipole moments, and all that (2002). arXiv preprint physics/0202029
Ido, T., Katori, H.: Recoil-free spectroscopy of neutral Sr atoms in the Lamb-Dicke regime. Phys. Rev. Lett. 91(5), 053001 (2003)
Martinez de Escobar, Y., Mickelson, P., Pellegrini, P., Nagel, S., Traverso, A., Yan, M., Côté, R., Killian, T.: Two-photon photoassociative spectroscopy of ultracold 88Sr. Phys. Rev. A 78, 062708 (2008)
McGuyer, B., McDonald, M., Iwata, G., Skomorowski, W., Moszynski, R., Zelevinsky, T.: Control of optical transitions with magnetic fields in weakly bound molecules. Phys. Rev. Lett. 115(5), 053001 (2015)
McGuyer, B., McDonald, M., Iwata, G., Tarallo, M., Grier, A., Apfelbeck, F., Zelevinsky, T.: High-precision spectroscopy of ultracold molecules in an optical lattice. New J. Phys. 17(5), 055004 (2015)
McGuyer, B., McDonald, M., Iwata, G., Tarallo, M., Skomorowski, W., Moszynski, R., Zelevinsky, T.: Precise study of asymptotic physics with subradiant ultracold molecules. Nat. Phys. 11(1), 32–36 (2015)
Metcalf, H., van der Straten, P.: Laser Cooling and Trapping. Graduate Texts in Contemporary Physics. Springer, New York (1999)
Osborn, C.: The physics of ultracold Sr2 molecules: optical production and precision measurement. PhD Thesis (2014)
Reinaudi, G., Osborn, C., McDonald, M., Kotochigova, S., Zelevinsky, T.: Optical production of stable ultracold 88Sr2 molecules. Phys. Rev. Lett. 109, 115303 (2012)
Skomorowski, W., Pawłowski, F., Koch, C., Moszynski, R.: Rovibrational dynamics of the strontium molecule in the \(A^1\varSigma _u^+\), c 3 Π u , and \(a^3\varSigma _u^+\) manifold from state-of-the-art ab initio calculations. J. Chem. Phys. 136(19), 194306 (2012)
Taichenachev, A., Yudin, V., Oates, C., Hoyt, C., Barber, Z., Hollberg, L.: Magnetic field-induced spectroscopy of forbidden optical transitions with application to lattice-based optical atomic clocks. Phys. Rev. Lett. 96(8), 083001 (2006)
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McDonald, M. (2018). Magnetic Control of Transition Strengths. In: High Precision Optical Spectroscopy and Quantum State Selected Photodissociation of Ultracold 88Sr2 Molecules in an Optical Lattice. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-319-68735-3_5
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DOI: https://doi.org/10.1007/978-3-319-68735-3_5
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