The first direct experimental observation of an electric quadrupole (E2) absorption transition between bound states of an atomic negative ion has been made. The transition was observed in the negative ion of bismuth by resonant (1 + 1) photon detachment from Bi- via P-3(2) -{\textgreater} P-3(0) excitation. The E2 transition properties were completely independently calculated using a hybrid theoretical approach to account for the strong multilevel electron interactions and relativistic effects. The experimental and ab initio theoretical results are in excellent agreement, providing valuable new insight into this complex system and forbidden transitions in negative ions more generally.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.126.083001}, author = {Walter, C. W. and Spielman, S. E. and Ponce, R. and Gibson, N. D. and Yukich, J. N. and Cheung, C. and Safronova, M. S.} } @article {safronova_predicting_2021, title = {Predicting quasibound states of negative ions: {La}- as a test case}, journal = {Phys. Rev. A}, volume = {103}, number = {2}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {feb}, abstract = {We demonstrated the accurate prediction of a quasibound spectrum of a negative ion using a high-precision theoretical approach. We used La as a test case due to a recent experiment that measured energies of 11 resonances in its photodetachment spectrum attributed to transitions to quasibound states [Phys. Rev. A 102, 042812 (2020)]. We identified all of the observed resonances and predicted one more peak just outside the range of the prior experiment. Following the theoretical prediction, the peak was observed at the predicted wavelength, validating the identification. The same approach is applicable to a wide range of negative ions.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.103.022819}, author = {Safronova, M. S. and Cheung, C. and Kozlov, M. G. and Spielman, S. E. and Gibson, N. D. and Walter, C. W.} } @article { ISI:000528518000008, title = {Accurate Prediction of Clock Transitions in a Highly Charged Ion with Complex Electronic Structure}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {16}, year = {2020}, month = {APR 24}, pages = {163001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We develop a broadly applicable approach that drastically increases the ability to predict the properties of complex atoms accurately. We apply it to the case of Ir-17(+), which is of particular interest for the development of novel atomic clocks with a high sensitivity to the variation of the fine-structure constant and to dark matter searches. In general, clock transitions are weak and very difficult to identify without accurate theoretical predictions. In the case of Ir-17(+), even stronger electric-dipole (El) transitions have eluded observation despite years of effort, raising the possibility that the theoretical predictions are grossly wrong. In this work, we provide accurate predictions of the transition wavelengths and E1 transition rates for Ir-17(+). Our results explain the lack of observations of the E1 transitions and provide a pathway toward the detection of clock transitions. The computational advances we demonstrate in this work are widely applicable to most elements in the periodic table and will allow us to solve numerous problems in atomic physics, astrophysics, and plasma physics.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.163001}, author = {Cheung, C. and Safronova, M. S. and Porsev, S. G. and Kozlov, M. G. and Tupitsyn, I. I. and Bondarev, I. A.} } @article {zhang_branching_2020, title = {Branching fractions for {P}-3/2 decays in {Ba}+}, journal = {Phys. Rev. A}, volume = {101}, number = {6}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jun}, abstract = {Branching fractions for decays from the P-3/2 level in B-138 at have been measured with a single laser-cooled ion. Decay probabilities to S-1/2, D-3/2, and D-5/2 are determined to be 0.741716(71), 0.028031(23), and 0.230253(61), respectively, which are an order-of-magnitude improvement over previous results. Our methodology only involves optical pumping and state detection, and is hence relatively free of systematic effects. Measurements are carried out in two different ways to check for consistency. Our analysis also includes a measurement of the D-5/2 lifetime, for which we obtain 30.14(40) s.}, issn = {1050-2947}, doi = {10.1103/PhysRevA.101.062515}, author = {Zhang, Zhiqiang and Arnold, K. J. and Chanu, S. R. and Kaewuam, R. and Safronova, M. S. and Barrett, M. D.} } @article { ISI:000548140000001, title = {Branching fractions for P-3/2 decays in Ba+}, journal = {Phys. Rev. A}, volume = {101}, number = {6}, year = {2020}, month = {JUN 24}, pages = {062515}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Branching fractions for decays from the P-3/2 level in B-138 at have been measured with a single laser-cooled ion. Decay probabilities to S-1/2, D-3/2, and D-5/2 are determined to be 0.741716(71), 0.028031(23), and 0.230253(61), respectively, which are an order-of-magnitude improvement over previous results. Our methodology only involves optical pumping and state detection, and is hence relatively free of systematic effects. Measurements are carried out in two different ways to check for consistency. Our analysis also includes a measurement of the D-5/2 lifetime, for which we obtain 30.14(40) s.}, issn = {1050-2947}, doi = {10.1103/PhysRevA.101.062515}, author = {Zhang, Zhiqiang and Arnold, K. J. and Chanu, S. R. and Kaewuam, R. and Safronova, M. S. and Barrett, M. D.} } @article { ISI:000550674500006, title = {Calculation of higher-order corrections to the light shift of the 5s(2) S-1(0)-5s5p P-3(0)o clock transition in Cd}, journal = {Phys. Rev. A}, volume = {102}, number = {1}, year = {2020}, month = {JUL 20}, pages = {012811}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {In the recent work by Yamaguchi et al. {[}Phys. Rev. Lett. 123, 113201 (2019)] Cd was identified as an excellent candidate for a lattice clock. Here, we carried out computations needed for further clock development and made an assessment of the higher-order corrections to the light shift of the 5s(2) S-1(0) -5s5p P-3(0)o clock transition. We carried out calculations of the magnetic dipole and electric quadrupole polarizabilities and linear and circular hyperpolarizabilities of the 5s(2) S-1(0) and 5s5p P-3(0)o clock states at the magic wavelength and estimated uncertainties of these quantities. We also evaluated the second-order Zeeman clock transition frequency shift.}, issn = {1050-2947}, doi = {10.1103/PhysRevA.102.012811}, author = {Porsev, S. G. and Safronova, M. S.} } @article {zhiqiang_hyperfine-mediated_2020, title = {Hyperfine-mediated effects in a {Lu}+ optical clock}, journal = {Phys. Rev. A}, volume = {102}, number = {5}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {nov}, abstract = {We consider hyperfine-mediated effects for clock transitions in Lu-176(+). Mixing of fine-structure levels due to the hyperfine interaction brings about modifications to the Lande g-factors and the quadrupole moment for a given state. Explicit expressions are derived for both the g-factor and quadrupole corrections, for which leading-order terms arise from the nuclear magnetic dipole coupling. High accuracy measurements of the g-factors for the S-1(0) and D-3(1) hyperfine levels are carried out, and they provide an experimental determination of the leading-order correction terms.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.102.052834}, author = {Zhiqiang, Zhang and Arnold, K. J. and Kaewuam, R. and Safronova, M. S. and Barrett, M. D.} } @article { ISI:000527491100005, title = {Magic wavelength of the Ba-138(+) 6s S-2(1/2)-5d D-2(5/2) clock transition}, journal = {Phys. Rev. A}, volume = {101}, number = {4}, year = {2020}, month = {APR 22}, pages = {042507}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The zero crossing of the dynamic differential scalar polarizability of the S-1/2 - D-5/2 clock transition in Ba-138(+) has been determined to be 459.1614(28) THz. Together with previously determined matrix elements and branching ratios, this tightly constrains the dynamic differential scalar polarizability of the clock transition over a large wavelength range (greater than or similar to 700 nm). In particular, it allows an estimate of the blackbody radiation shift of the clock transition at room temperature.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.042507}, author = {Chanu, S. R. and Koh, V. P. W. and Arnold, K. J. and Kaewuam, R. and Tan, T. R. and Zhang, Zhiqiang and Safronova, M. S. and Barrett, M. D.} } @article {zheng_magic_2020, title = {Magic wavelengths of the {Yb} (6s(2) {S}-1(0)-6s6p {P}-3(1)) intercombination transition}, journal = {Phys. Rev. A}, volume = {102}, number = {6}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {We calculate and measure the magic wavelengths for the 6s(2) S-1(0)-6s6p P-3(1) intercombination transition of the neutral ytterbium atom. The calculation is performed with the ab initio configuration interaction + all-order method. The measurement is done with laser spectroscopy on cold atoms in an optical dipole trap. The magic wavelengths are determined to be 1035.68(4) nm for the pi transition (Delta m = 0) and 1036.12(3) nm for the sigma transitions (vertical bar Delta m vertical bar = 1) in agreement with the calculated values. Laser cooling on the narrow intercombination transition could achieve better results for atoms in an optical dipole trap when the trap wavelength is tuned to near the magic wavelength.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.102.062805}, author = {Zheng, T. A. and Yang, Y. A. and Safronova, M. S. and Safronova, I, U. and Xiong, Zhuan-Xian and Xia, T. and Lu, Z-T} } @article { ISI:000548284200010, title = {Optical clocks based on the Cf15+ and Cf17+ ions}, journal = {Phys. Rev. A}, volume = {102}, number = {1}, year = {2020}, month = {JUL 6}, pages = {012802}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Recent experimental progress in cooling, trapping, and quantum logic spectroscopy of highly charged ions (HCIs) made HCIs accessible for high-resolution spectroscopy and precision fundamental studies. Based on these achievements, we explore a possibility to develop optical clocks using transitions between the ground and a low-lying excited state in Cf15+ and Cf17+ ions. Using a high-accuracy relativistic method of calculation, we predicted the wavelengths of clock transitions, calculated relevant atomic properties, and analyzed a number of systematic effects (such as the electric quadrupole, micromotion, and quadratic Zeeman shifts of the clock transitions) that affect the accuracy and stability of the optical clocks. We also calculated magnetic dipole hyperfine-structure constants of the clock states and the blackbody radiation shifts of the clock transitions.}, issn = {1050-2947}, doi = {10.1103/PhysRevA.102.012802}, author = {Porsev, S. G. and Safronova, I, U. and Safronova, M. S. and Schmidt, P. O. and Bondarev, I, A. and Kozlov, M. G. and Tupitsyn, I. I. and Cheung, C.} } @article { ISI:000533504100003, title = {State-Dependent Optical Lattices for the Strontium Optical Qubit}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {20}, year = {2020}, month = {MAY 18}, pages = {203201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate state-dependent optical lattices for the Sr optical qubit at the tune-out wavelength for its ground state. We tightly trap excited state atoms while suppressing the effect of the lattice on ground state atoms by more than 4 orders of magnitude. This highly independent control over the qubit states removes inelastic excited state collisions as the main obstacle for quantum simulation and computation schemes based on the Sr optical qubit. Our results also reveal large discrepancies in the atomic data used to calibrate the largest systematic effect of Sr optical lattice clocks.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.203201}, author = {Heinz, A. and Park, A. J. and Santi, N. and Trautmann, J. and Porsev, S. G. and Safronova, M. S. and Bloch, I and Blatt, S.} } @article {ISI:000455814100005, title = {Dynamic polarizability measurements with Lu-176(+)}, journal = {Phys. Rev. A}, volume = {99}, number = {1}, year = {2019}, month = {JAN 15}, pages = {012510}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We measure the differential polarizability of the Lu-176(+) S-1(0) <-> D-3(1) clock transition at multiple wavelengths. This experimentally characterizes the differential dynamic polarizability for frequencies up to 372 THz and allows an experimental determination of the dynamic correction to the blackbody radiation shift for the clock transition. In addition, measurements at the near resonant wavelengths of 598 and 646 nm determine the two dominant contributions to the differential dynamic polarizability below 372 THz. These additional measurements are carried out by two independent methods to verify the validity of our methodology. We also carry out a theoretical calculation of the polarizabilities using the hybrid method that combines the configuration interaction (CI) and the coupled-cluster approaches, incorporating for the first time quadratic nonlinear terms and partial triple excitations in the coupled-cluster calculations. The experimental measurements of the vertical bar < D-3(1)parallel to r parallel to P-3(J)>vertical bar matrix elements provide high-precision benchmarks for this theoretical approach.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.012510}, author = {Arnold, K. J. and Kaewuam, R. and Tan, T. R. and Porsev, S. G. and Safronova, M. S. and Barrett, M. D.} } @article {ISI:000460648100005, title = {Electric dipole matrix elements for the 6p(2)P(J) -> 7s(2)S(1/2) transition in atomic cesium}, journal = {Phys. Rev. A}, volume = {99}, number = {3}, year = {2019}, month = {MAR 5}, pages = {032504}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report a measurement of the ratio of electric dipole transition matrix elements of cesium for the 6p(2)P(1/2) -> 7s(2)S(1/2) and 6p(2)P(3/2) -> 7s(2)S(1/2 )transitions. We determine this ratio of matrix elements through comparisons of two-color, two-photon excitation rates of the 7s(2)S(1/2) state using laser beams with polarizations parallel to one another vs perpendicular to one another. Our result of R < 7s(2)S(1/2)parallel to r parallel to 6P(2)P(3/2)>/< 7s(2)S(1/2)parallel to r parallel to 6P(2)P(1/2)> = 1.5272(17) is in excellent agreement with a theoretical prediction of R = 1.5270(27). Moreover, the accuracy of the experimental ratio is sufficiently high to differentiate between various theoretical approaches. To our knowledge, there are no prior experimental measurements of R. Combined with our recent determination of the lifetime of the 7s(2)S(1/2) state, we determine reduced matrix elements for these two transitions, < 7s(2)S(1/2)parallel to r parallel to 6P(2)P(3/2)> = -6.489(5)a(0) and < 7s(2)S(1/2)parallel to r parallel to 6P(2)P(1/2 >) = -4.249(4)a(0). These matrix elements are also in excellent agreement with theoretical calculations. These measurements improve knowledge of Cs properties needed for parity violation studies and provide benchmarks for tests of high-precision theory.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.032504}, author = {Toh, George and Damitz, Amy and Glotzbach, Nathan and Quirk, Jonah and Stevenson, I. C. and Choi, J. and Safronova, M. S. and Elliott, D. S.} } @article { ISI:000496923500007, title = {High-precision measurement and ab initio calculation of the (6s(2)6p(2)) P-3(0) -> P-3(2) electric-quadrupole-transition amplitude in Pb-208}, journal = {Phys. Rev. A}, volume = {100}, number = {5}, year = {2019}, month = {NOV 18}, pages = {052506}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We have completed a measurement of the (6s(2)6p(2)) P-3(0) -> P-3(2) 939 nm electric quadrupole (E2) transition amplitude in atomic lead. Using a Faraday rotation spectroscopy technique and a sensitive polarimeter, we have measured this very weak E2 transition, and determined its amplitude to be < P-3(2) parallel to Q parallel to P-3(0)> = 8.91(9) a.u. We also present an ab initio theoretical calculation of this matrix element, determining its value to be 8.86(5) a.u., which is in excellent agreement with the experimental result. We heat a quartz vapor cell containing Pb-208 to between 800 and 940 degrees C, apply a similar to 10 G longitudinal magnetic field, and use polarization modulation and lock-in detection to measure optical rotation amplitudes of order 1 mrad with noise near 1 mu rad. We compare the Faraday rotation amplitude of the E2 transition to that of the P-3(0)-P-3(1) 1279 nm magnetic dipole (M1) transition under identical sample conditions.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.052506}, author = {Maser, Daniel L. and Hoenig, Eli and Wang, B-Y and Rupasinghe, P. M. and Porsev, S. G. and Safronova, M. S. and Majumder, P. K.} } @article { ISI:000501342800003, title = {Measurement of the 7p P-2(3/2) state branching fractions in Ra+}, journal = {Phys. Rev. A}, volume = {100}, number = {6}, year = {2019}, month = {DEC 6}, pages = {062504}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report a measurement of the radium ion{\textquoteright}s 7p(2)P(3/2) state branching fractions and improved theoretical calculations. With a single laser-cooled Ra-226(+) ion we measure the P-3/2 branching fractions to the 7s(2)S(1/2) ground state 0.876 78(20), the 6d D-2(5/2) state 0.107 59(10), and the 6d D-2(3/2) state 0.015 63(21).}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.062504}, author = {Fan, M. and Holliman, C. A. and Porsev, S. G. and Safronova, M. S. and Jayich, A. M.} } @article {ISI:000483578600012, title = {Measurements of the branching ratios for 6P(1/2) decays in Ba-138(+)}, journal = {Phys. Rev. A}, volume = {100}, number = {3}, year = {2019}, month = {SEP 3}, pages = {032503}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Measurement of the branching ratios for 6P(1/2) decays to 6S(1/2) and 5D(3/2) in Ba-138(+) are reported with the decay probability from 6P(1/2) to 5D(3/2) measured to be p = 0.268177 +/- (37)(stat)-(20)(sys). This result differs from a recent report by 12 sigma. A detailed account of systematics is given, and the likely source of the discrepancy is identified. The new value of the branching reported here is combined with previous experimental results to give a new estimate of tau = 7.855(10) ns for the 6P(1/2) lifetime. In addition, ratios of matrix elements calculated from theory are combined with experimental results to provide improved theoretical estimates of the 6P(3/2) lifetime and the associated matrix elements.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.032503}, author = {Arnold, K. J. and Chanu, S. R. and Kaewuam, R. and Tan, T. R. and Yeo, L. and Zhang, Zhiqiang and Safronova, M. S. and Barrett, M. D.} } @article {ISI:000485768100009, title = {Narrow-line Cooling and Determination of the Magic Wavelength of Cd}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {11}, year = {2019}, month = {SEP 13}, pages = {113201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We experimentally and theoretically determine the magic wavelength of the (5s(2))S-1(0) - (5s5p)P-3(0) clock transition of Cd-111 to be 419.88(14) and 420.1(7) nm. To perform Lamb-Dicke spectroscopy of the clock transition, we use narrow-line laser cooling on the S-1(0) - P-3(1) transition to cool the atoms to 6 mu K and load them into an optical lattice. Cadmium is an attractive candidate for optical lattice clocks because it has a small sensitivity to blackbody radiation and its efficient narrow-line cooling mitigates higher order light shifts. We calculate the blackbody shift, including the dynamic correction, to be fractionally 2.83(8) x 10(-16) at 300 K, an order of magnitude smaller than that of Sr and Yb. We also report calculations of the Cd P-1(1) lifetime and the ground state C-6 coefficient.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.113201}, author = {Yamaguchi, A. and Safronova, M. S. and Gibble, K. and Katori, H.} } @article { ISI:000492332900006, title = {Polarizability assessments of ion-based optical clocks}, journal = {Phys. Rev. A}, volume = {100}, number = {4}, year = {2019}, month = {OCT 24}, pages = {043418}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {It is shown that the dynamic differential scalar polarizability of the S-1/2 - D-5/2 transition in Ba-138(+) can be determined to an inaccuracy below 0.5\% across a wide wavelength range (lambda > 700 nm). This can be achieved using measurements for which accurate determination of laser intensity is not required, and most of the required measurements are already in the literature. Measurement of a laser-induced ac-Stark shift of the clock transition would then provide an in situ measurement of the laser{\textquoteright}s intensity to the same 0.5\% level of inaccuracy, which is not easily achieved by other means. This would allow accurate polarizability measurements for clock transitions in other ions, through comparison with Ba-138(+). The approach would be equally applicable to Sr+ and Ca+, with the latter being immediately applicable to Al+/Ca+ quantum logic clocks.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.043418}, author = {Barrett, M. D. and Arnold, K. J. and Safronova, M. S.} } @article {ISI:000479034100005, title = {Suppressing Inhomogeneous Broadening in a Lutetium Multi-ion Optical Clock}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {6}, year = {2019}, month = {AUG 7}, pages = {063201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate precision measurement and control of inhomogeneous broadening in a multi-ion clock consisting of three Lu-176(+) ions. Microwave spectroscopy between hyperfine states in the D-3(1) level is used to characterize differential systematic shifts between ions, most notably those associated with the electric quadrupole moment. By appropriate alignment of the magnetic field, we demonstrate suppression of these effects to the similar to 10(-17) level relative to the S-1(0) <-> D-3(1) optical transition frequency. Correlation spectroscopy on the optical transition demonstrates the feasibility of a 10-s Ramsey interrogation in the three ion configuration with a corresponding projection noise limited stability of sigma(tau) = 8.2 x 10(-17)/root tau.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.063201}, author = {Tan, T. R. and Kaewuam, R. and Arnold, K. J. and Chanu, S. R. and Zhang, Zhiqiang and Safronova, M. S. and Barrett, M. D.} } @article { ISI:000423426200008, title = {Atomic properties of actinide ions with particle-hole configurations}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {1}, year = {2018}, month = {JAN 25}, pages = {012511}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.012511}, author = {Safronova, M. S. and Safronova, U. I. and Kozlov, M. G.} } @article { ISI:000441668600006, title = {Clock-related properties of Lu+}, journal = {PHYSICAL REVIEW A}, volume = {98}, number = {2}, year = {2018}, month = {AUG 14}, pages = {022509}, issn = {2469-9926}, doi = {10.1103/PhysRevA.98.022509}, author = {Porsev, S. G. and Safronova, U. I. and Safronova, M. S.} } @article { ISI:000451992400001, title = {Highly charged ions: Optical clocks and applications in fundamental physics}, journal = {REVIEWS OF MODERN PHYSICS}, volume = {90}, number = {4}, year = {2018}, month = {DEC 4}, pages = {045005}, abstract = {Recent developments in frequency metrology and optical clocks have been based on electronic transitions in atoms and singly charged ions as references. The control over all relevant degrees of freedom in these atoms has enabled relative frequency uncertainties at a level of 10(-18). This accomplishment not only allows for extremely accurate time and frequency measurements, but also to probe our understanding of fundamental physics, such as a possible variation of fundamental constants, a violation of the local Lorentz invariance, and the existence of forces beyond the standard model of physics. In addition, novel clocks are driving the development of sophisticated technical applications. Crucial for applications of clocks in fundamental physics are a high sensitivity to effects beyond the standard model and a small frequency uncertainty of the clock. Highly charged ions offer both. They possess optical transitions which can be extremely narrow and less sensitive to external perturbations compared to current atomic clock species. The large selection of highly charged ions offers narrow transitions that are among the most sensitive ones for the {\textquoteleft}{\textquoteleft}new physics{{\textquoteright}{\textquoteright}} effects. Recent experimental advances in trapping and sympathetic cooling of highly charged ions will in the future enable advanced quantum logic techniques for controlling motional and internal degrees of freedom and thus enable high-accuracy optical spectroscopy. Theoretical progress in calculating the properties of selected highly charged ions has allowed the evaluation of systematic shifts and the prediction of the sensitivity to the physics beyond the standard model. New theoretical challenges and opportunities emerge from relativistic, quantum electrodynamics, and nuclear-size contributions that become comparable with interelectronic correlations. This article reviews the current status of the field, addresses specific electronic configurations and systems which show the most promising properties for research, their potential limitations, and the techniques for their study.}, issn = {0034-6861}, doi = {10.1103/RevModPhys.90.045005}, author = {Kozlov, M. G. and Safronova, M. S. and Lopez-Urrutia, J. R. Crespo and Schmidt, P. O.} } @article { ISI:000425089500005, title = {High-precision measurements and theoretical calculations of indium excited-state polarizabilities}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {2}, year = {2018}, month = {FEB 15}, pages = {022507}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.022507}, author = {Vilas, N. B. and Wang, B. -Y. and Rupasinghe, P. M. and Maser, D. L. and Safronova, M. S. and Safronova, U. I. and Majumder, P. K.} } @article { ISI:000424507800014, title = {Multipolar Polarizabilities and Hyperpolarizabilities in the Sr Optical Lattice Clock}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {6}, year = {2018}, month = {FEB 8}, pages = {063204}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.063204}, author = {Porsev, S. G. and Safronova, M. S. and Safronova, U. I. and Kozlov, M. G.} } @article { ISI:000427007200003, title = {New Methods for Testing Lorentz Invariance with Atomic Systems}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {10}, year = {2018}, month = {MAR 8}, pages = {103202}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.103202}, author = {Shaniv, R. and Ozeri, R. and Safronova, M. S. and Porsev, S. G. and Dzuba, V. A. and flambaum, v. v. and Haffner, H.} } @article { ISI:000451329500021, title = {Nobelium energy levels and hyperfine-structure constants}, journal = {PHYSICAL REVIEW A}, volume = {98}, number = {5}, year = {2018}, month = {NOV 26}, pages = {052512}, abstract = {Advances in laser spectroscopy of superheavy (Z > 100) elements enabled determination of the nuclear moments of the heaviest nuclear which required high-precision atomic calculations of the relevant hyperfine-structure (hfs) constants. Here, we calculated the hfs constants and energy levels for a number of nobelium (Z = 102) states using a hybrid approach combining linearized coupled-cluster and configuration interaction methods. We also carried out an extensive study of the No energies using the 16-electro configuration interaction method to determine the position of the 5f(13)7s(2)6d and 5f(13)7s(2)7p levels with a hole in the 5 f shell to evaluate their potential effect on the hyperfine-structure calculations of the low-lying 5f(14)7s6d and 5f(14)7s7p levels. We find that unlike the case of Yb, the mixing of the low-lying levels with filled and unfilled f shells is small and does not significantly influence their properties. The resulting hfs constants for the 5f(14)7s7p P-1(1)0 level, combined with laser-spectroscopy measurement, were used to extract nobelium nuclear properties.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.98.052512}, author = {Porsev, S. G. and Safronova, M. S. and Safronova, I, U. and Dzuba, V. A. and flambaum, v. v.} } @article { ISI:000451010600006, title = {Nuclear Charge Radii of Th-229 from Isotope and Isomer Shifts}, journal = {PHYSICAL REVIEW LETTERS}, volume = {121}, number = {21}, year = {2018}, month = {NOV 21}, pages = {213001}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.121.213001}, author = {Safronova, M. S. and Porsev, S. G. and Kozlov, M. G. and Thielking, J. and Okhapkin, M. V. and Glowacki, P. and Meier, D. M. and Peik, E.} } @article { ISI:000434633000006, title = {Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {23}, year = {2018}, month = {JUN 8}, pages = {232503}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.232503}, author = {Raeder, S. and Ackermann, D. and Backe, H. and Beerwerth, R. and Berengut, J. C. and Block, M. and Borschevsky, A. and Cheal, B. and Chhetri, P. and Duellmann, Ch. E. and Dzuba, V. A. and Eliav, E. and Even, J. and Ferrer, R. and flambaum, v. v. and Fritzsche, S. and Giacoppo, F. and Goetz, S. and Hessberger, F. P. and Huyse, M. and Kaldor, U. and Kaleja, O. and Khuyagbaatar, J. and Kunz, P. and Laatiaoui, M. and Lautenschlager, F. and Lauth, W. and Mistry, A. K. and Ramirez, E. Minaya and Nazarewicz, W. and Porsev, S. G. and Safronova, M. S. and Safronova, U. I. and Schuetrumpf, B. and Van Duppen, P. and Walther, T. and Wraith, C. and Yakushev, A.} } @article { ISI:000419097100004, title = {Relativistic all-order many-body calculation of energies, wavelengths, and M1 and E2 transition rates for the 3d(n) configurations in tungsten ions}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {1}, year = {2018}, month = {JAN 3}, pages = {012502}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.012502}, author = {Safronova, M. S. and Safronova, U. I. and Porsev, S. G. and Kozlov, M. G. and Ralchenko, Yu.} } @article { ISI:000436944600001, title = {Search for new physics with atoms and molecules}, journal = {REVIEWS OF MODERN PHYSICS}, volume = {90}, number = {2}, year = {2018}, month = {JUN 29}, pages = {025008}, issn = {0034-6861}, doi = {10.1103/RevModPhys.90.025008}, author = {Safronova, M. S. and Budker, D. and DeMille, D. and Kimball, Derek F. Jackson and Derevianko, A. and Clark, Charles W.} } @article { ISI:000428507500006, title = {Ultracold Anions for High-Precision Antihydrogen Experiments}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {13}, year = {2018}, month = {MAR 28}, pages = {133205}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.133205}, author = {Cerchiari, G. and Kellerbauer, A. and Safronova, M. S. and Safronova, U. I. and Yzombard, P.} } @article { ISI:000405362900007, title = {Theoretical study of the g factor and lifetime of the 6s6 p P-3(0) state of mercury}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {1}, year = {2017}, month = {JUL 13}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.012509}, author = {Porsev, S. G. and Safronova, U. I. and Safronova, M. S.} } @article {ISI:000379697900007, title = {Magic wavelengths, matrix elements, polarizabilities, and lifetimes of Cs}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {1}, year = {2016}, month = {JUL 6}, pages = {012505}, abstract = {Motivated by recent interest in their applications, we report a systematic study of Cs atomic properties calculated by a high-precision relativistic all-order method. Excitation energies, reduced matrix elements, transition rates, and lifetimes are determined for levels with principal quantum numbers n <= 12 and orbital angular momentum quantum numbers l <= 3. Recommended values and estimates of uncertainties are provided for a number of electric-dipole transitions and the electric dipole polarizabilities of the ns, np, and nd states. We also report a calculation of the electric quadrupole polarizability of the ground state. We display the dynamic polarizabilities of the 6s and 7p states for optical wavelengths between 1160 and 1800 nm and identify corresponding magic wavelengths for the 6s - 7p(1/2) and 6s - 7p(3/2) transitions. The values of relevant matrix elements needed for polarizability calculations at other wavelengths are provided.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.012505}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @conference { ISI:000354845400009, title = {Atomic Polarizabilities}, booktitle = {PROCEEDINGS OF THE INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2010 (ICCMSE-2010)}, series = {AIP Conference Proceedings}, volume = {1642}, year = {2015}, note = {International Conference of Computational Methods in Sciences and Engineering (ICCMSE), Kos, GREECE, OCT 03-08, 2010}, pages = {81-89}, isbn = {978-0-7354-1282-8}, issn = {0094-243X}, doi = {10.1063/1.4906633}, author = {Safronova, M. S. and Mitroy, J. and Clark, Charles W. and Kozlov, M. G.}, editor = {Simos, TE and Maroulis, G} } @article { ISI:000357750100019, title = {CI-MBPT: A package of programs for relativistic atomic calculations based on a method combining configuration interaction and many-body perturbation theory}, journal = {COMPUTER PHYSICS COMMUNICATIONS}, volume = {195}, year = {2015}, month = {OCT}, pages = {199-213}, issn = {0010-4655}, doi = {10.1016/j.cpc.2015.05.007}, author = {Kozlov, M. G. and Porsev, S. G. and Safronova, M. S. and Tupitsyn, I. I.} } @article { ISI:000350169700003, title = {Correlation effects in La, Ce, and lanthanide ions}, journal = {PHYSICAL REVIEW A}, volume = {91}, number = {2}, year = {2015}, month = {FEB 9}, pages = {022504}, issn = {1050-2947}, doi = {10.1103/PhysRevA.91.022504}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @article { ISI:000362342200001, title = {Extracting transition rates from zero-polarizability spectroscopy}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {4}, year = {2015}, month = {OCT 6}, pages = {040501}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.040501}, author = {Safronova, M. S. and Zuhrianda, Z. and Safronova, U. I. and Clark, Charles W.} } @article { ISI:000348775000038, title = {Michelson-Morley analogue for electrons using trapped ions to test Lorentz symmetry}, journal = {NATURE}, volume = {517}, number = {7536}, year = {2015}, month = {JAN 29}, pages = {592-U357}, issn = {0028-0836}, doi = {10.1038/nature14091}, author = {Pruttivarasin, T. and Ramm, M. and Porsev, S. G. and Tupitsyn, I. I. and Safronova, M. S. and Hohensee, M. A. and Haeffner, H.} } @article { ISI:000359984400001, title = {Observation of an unexpected negative isotope shift in Th-229(+) and its theoretical explanation}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {2}, year = {2015}, month = {AUG 25}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.020503}, author = {Okhapkin, M. V. and Meier, D. M. and Peik, E. and Safronova, M. S. and Kozlov, M. G. and Porsev, S. G.} } @article { ISI:000353704100004, title = {Systematic evaluation of an atomic clock at 2 x 10 (-18) total uncertainty}, journal = {NATURE COMMUNICATIONS}, volume = {6}, year = {2015}, month = {APR}, issn = {2041-1723}, doi = {10.1038/ncomms7896}, author = {Nicholson, T. L. and S. L. Campbell and Hutson, R. B. and Marti, G. E. and Bloom, B. J. and McNally, R. L. and Zhang, W. and Barrett, M. D. and Safronova, M. S. and Strouse, G. F. and Tew, W. L. and Ye, J.} } @article { ISI:000359045200004, title = {Transitions between the 4f-core-excited states in Ir16+, Ir17+, and Ir18+ ions for clock applications}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {2}, year = {2015}, month = {AUG 5}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.022501}, author = {Safronova, U. I. and flambaum, v. v. and Safronova, M. S.} } @article { ISI:000348766800006, title = {Atomic properties of Cd-like and Sn-like ions for the development of frequency standards and search for the variation of the fine-structure constant}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {5}, year = {2014}, month = {NOV 13}, issn = {1050-2947}, doi = {10.1103/PhysRevA.90.052509}, author = {Safronova, M. S. and Dzuba, V. A. and flambaum, v. v. and Safronova, U. I. and Porsev, S. G. and Kozlov, M. G.} } @article { ISI:000338491500003, title = {Atomic properties of superheavy elements No, Lr, and Rf}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {1}, year = {2014}, month = {JUL 3}, issn = {1050-2947}, doi = {10.1103/PhysRevA.90.012504}, author = {Dzuba, V. A. and Safronova, M. S. and Safronova, U. I.} } @article { ISI:000344028800006, title = {Highly charged Ag-like and In-like ions for the development of atomic clocks and the search for alpha variation}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {4}, year = {2014}, month = {OCT 31}, issn = {1050-2947}, doi = {10.1103/PhysRevA.90.042513}, author = {Safronova, M. S. and Dzuba, V. A. and flambaum, v. v. and Safronova, U. I. and Porsev, S. G. and Kozlov, M. G.} } @article { ISI:000345598400001, title = {Relativistic all-order calculations of Th, Th+, and Th2+ atomic properties}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {3}, year = {2014}, month = {SEP 25}, issn = {1050-2947}, doi = {10.1103/PhysRevA.90.032512}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @article { ISI:000345243200006, title = {Relativistic calculations of C-6 and C-8 coefficients for strontium dimers}, journal = {PHYSICAL REVIEW A}, volume = {90}, number = {5}, year = {2014}, month = {NOV 18}, issn = {1050-2947}, doi = {10.1103/PhysRevA.90.052715}, author = {Porsev, S. G. and Safronova, M. S. and Clark, Charles W.} } @article { ISI:000339552500004, title = {Relativistic many-body calculation of energies, transition rates, lifetimes, and multipole polarizabilities in Cs-like La III}, journal = {PHYSICAL REVIEW A}, volume = {89}, number = {5}, year = {2014}, month = {MAY 20}, issn = {1050-2947}, doi = {10.1103/PhysRevA.89.052515}, author = {Safronova, U. I. and Safronova, M. S.} } @article { ISI:000341752900033, title = {Spectroscopic observation of SU(N)-symmetric interactions in Sr orbital magnetism}, journal = {SCIENCE}, volume = {345}, number = {6203}, year = {2014}, month = {SEP 19}, pages = {1467-1473}, issn = {0036-8075}, doi = {10.1126/science.1254978}, author = {Zhang, X. and Bishof, M. and S. L. Bromley and Kraus, C. V. and Safronova, M. S. and Zoller, P. and Rey, A. M. and Ye, J.} } @article { ISI:000315726900002, title = {Critically evaluated theoretical atomic properties of Y III}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 5}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032501}, author = {Safronova, U. I. and Safronova, M. S.} } @article { ISI:000332103500001, title = {Magnetic dipole and electric quadrupole moments of the Th-229 nucleus}, journal = {PHYSICAL REVIEW A}, volume = {88}, number = {6}, year = {2013}, month = {DEC 26}, issn = {1050-2947}, doi = {10.1103/PhysRevA.88.060501}, author = {Safronova, M. S. and Safronova, U. I. and Radnaev, A. G. and Campbell, C. J. and A. Kuzmich} } @article { ISI:000316412900002, title = {Polarizabilities, Stark shifts, and lifetimes of the In atom}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 21}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032513}, author = {Safronova, M. S. and Safronova, U. I. and Porsev, S. G.} } @article { ISI:000315727700007, title = {Relativistic many-body calculation of energies, lifetimes, polarizabilities, and hyperpolarizabilities in Li-like Be+}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 7}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032502}, author = {Safronova, U. I. and Safronova, M. S.} } @article { ISI:000320760800006, title = {Relativistic many-body calculation of energies, oscillator strengths, transition rates, lifetimes, polarizabilities, and quadrupole moment of a Fr-like Th IV ion}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {6}, year = {2013}, month = {JUN 20}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.062509}, author = {Safronova, M. S. and Safronova, U. I.} } @article { ISI:000317097400005, title = {Thallium 7p lifetimes derived from experimental data and ab initio calculations of scalar polarizabilities}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {4}, year = {2013}, month = {APR 3}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.042502}, author = {Safronova, M. S. and Majumder, P. K.} } @article {2542, title = {Magic wavelengths for optical cooling and trapping of lithium}, journal = {PHYSICAL REVIEW A}, volume = {86}, year = {2012}, month = {OCT 10}, pages = {042505}, issn = {1050-2947}, doi = {10.1103/PhysRevA.86.042505}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @article {2534, title = {Polarizabilities of Si2+: A benchmark test of theory and experiment}, journal = {PHYSICAL REVIEW A}, volume = {85}, year = {2012}, month = {MAY 14}, pages = {052506}, issn = {1050-2947}, doi = {10.1103/PhysRevA.85.052506}, author = {Safronova, M. S. and Porsev, S. G. and Kozlov, M. G. and Clark, Charles W.} } @article {2554, title = {Precision Calculation of Blackbody Radiation Shifts for Optical Frequency Metrology}, journal = {PHYSICAL REVIEW LETTERS}, volume = {107}, year = {2011}, month = {SEP 30}, pages = {143006}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.107.143006}, author = {Safronova, M. S. and Kozlov, M. G. and Clark, Charles W.} }