@article { ISI:000507490800005,
title = {Combining experiments and relativistic theory for establishing accurate radiative quantities in atoms: The lifetime of the P-2(3/2) state in Ca-40(+)},
journal = {Phys. Rev. A},
volume = {101},
number = {1},
year = {2020},
month = {JAN 14},
pages = {012509},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We report a precise determination of the lifetime of the (4p) P-2(3/2) state of Ca-40(+), tau(p3/2) = 6.639(42) ns, using a combination of measurements of the induced light shift and scattering rate on a single trapped ion. Good agreement with the result of a recent high-level theoretical calculation, 6.69(6) ns {[}M. S. Safronova et al., Phys. A 83, 012503 (2011)], but a 6-sigma discrepancy with the most precise previous experimental value, 6.924(19) ns {[}J. Jin et al., Phys. Rev. Lett. 70, 3213 (1993)], is found. To corroborate the consistency and accuracy of the new measurements, relativistically corrected ratios of reduced-dipole-matrix elements are used to directly compare our result with a recent result for the P-1/2 state, yielding a good agreement. The application of the present method to precise determinations of radiative quantities of molecular systems is discussed.},
issn = {2469-9926},
doi = {10.1103/PhysRevA.101.012509},
author = {Meir, Ziv and Sinhal, Mudit and Safronova, Marianna S. and Willitsch, Stefan}
}
@article { ISI:000557736300003,
title = {Detection of the Lowest-Lying Odd-Parity Atomic Levels in Actinium},
journal = {Phys. Rev. Lett.},
volume = {125},
number = {7},
year = {2020},
month = {AUG 10},
pages = {073001},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {Two lowest-energy odd-parity atomic levels of actinium, 7s(2)7p(2)P(1/2)(0), 7s(2)7p(2)P(3/)(2)(0), were observed via two-step resonant laser-ionization spectroscopy and their respective energies were measured to be 7477.36(4) and 12 276.59(2) cm(-1). The lifetimes of these states were determined as 668(11) and 255(7) ns, respectively. In addition, we observed the effect of the hyperfine structure on the line for the transition to P-2(3)/2(0). These properties were calculated using a hybrid approach that combines configuration interaction and coupled-cluster methods, in good agreement with the experiment. The data are of relevance for understanding the complex atomic spectra of actinides and for developing efficient laser cooling and ionization schemes for actinium, with possible applications for high-purity medical-isotope production and future fundamental physics experiments.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.125.073001},
author = {Zhang, Ke and Studer, Dominik and Weber, Felix and Gadelshin, Vadim M. and Kneip, Nina and Raeder, Sebastian and Budker, Dmitry and Wendt, Klaus and Kieck, Tom and Porsev, Sergey G. and Cheung, Charles and Safronova, Marianna S. and Kozlov, Mikhail G.}
}
@article {kuehn_high_2020,
title = {High {Resolution} {Photoexcitation} {Measurements} {Exacerbate} the {Long}-{Standing} {Fe} {XVII} {Oscillator} {Strength} {Problem},
journal = {Phys. Rev. Lett.},
volume = {124},
number = {22},
year = {2020},
note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article},
month = {jun},
abstract = {For more than 40 years, most astrophysical observations and laboratory studies of two key soft x-ray diagnostic 2p - 3d transitions, 3C and 3D, in Fe XVII ions found oscillator strength ratios f(3C)/f(3D) disagreeing with theory, but uncertainties had precluded definitive statements on this much studied conundrum. Here, we resonantly excite these lines using synchrotron radiation at PETRA III, and reach, at a millionfold lower photon intensities, a 10 times higher spectral resolution, and 3 times smaller uncertainty than earlier work. Our final result of f(3C)/f(3D) = 3.09(8)(6) supports many of the earlier clean astrophysical and laboratory observations, while departing by five sigmas from our own newest large-scale ab initio calculations, and excluding all proposed explanations, including those invoking nonlinear effects and population transfers.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.124.225001},
author = {Kuehn, Steffen and Shah, Chintan and Lopez-Urrutia, Jose R. Crespo and Fujii, Keisuke and Steinbruegge, Rene and Stierhof, Jakob and Togawa, Moto and Harman, Zoltan and Oreshkina, Natalia S. and Cheung, Charles and Kozlov, Mikhail G. and Porsev, Sergey G. and Safronova, Marianna S. and Berengut, Julian C. and Rosner, Michael and Bissinger, Matthias and Ballhausen, Ralf and Hell, Natalie and Park, SungNam and Chung, Moses and Hoesch, Moritz and Seltmann, Joern and Surzhykov, Andrey S. and Yerokhin, Vladimir A. and Wilms, Joern and Porter, F. Scott and Stoehlker, Thomas and Keitel, Christoph H. and Pfeifer, Thomas and Brown, V, Gregory and Leutenegger, Maurice A. and Bernitt, Sven}
}
@article { ISI:000555932400003,
title = {Probing the relaxed relaxion at the luminosity and precision frontiers},
journal = {J. High Energy Phys.},
number = {7},
year = {2020},
month = {JUL 22},
pages = {153},
publisher = {SPRINGER},
type = {Article},
abstract = {Cosmological relaxation of the electroweak scale is an attractive scenario relaxion, is a light spin-zero field which dynamically relaxes the Higgs mass with respect to its natural large value. We show that the relaxion is generically stabilized at a special position in the field space, which leads to suppression of its mass and potentially unnatural values for the model{\textquoteright}s effective low-energy couplings. In particular, we find that the relaxion mixing with the Higgs can be several orders of magnitude above its naive naturalness bound. Low energy observers may thus find the relaxion theory being fine-tuned although the relaxion scenario itself is constructed in a technically natural way. More generally, we identify the lower and upper bounds on the mixing angle. We examine the experimental implications of the above observations at the luminosity and precision frontiers. A particular attention is given to the impressive ability of future nuclear clocks to search for rapidly oscillating scalar ultra-light dark matter, where the future projected sensitivity is presented.},
keywords = {Beyond Standard Model, Cosmology of Theories beyond the SM},
issn = {1029-8479},
doi = {10.1007/JHEP07(2020)153},
author = {Banerjee, Abhishek and Kim, Hyungjin and Matsedonskyi, Oleksii and Perez, Gilad and Safronova, Marianna S.}
}
@article {ISI:000482940400006,
title = {Frequency shifts due to Stark effects on a rubidium two-photon transition},
journal = {Phys. Rev. A},
volume = {100},
number = {2},
year = {2019},
month = {AUG 28},
pages = {023417},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {The 5S(1/2) -> 5D(5/2) two-photon transition in Rb is of interest for the development of a compact optical atomic clock. Here we present a rigorous calculation of the 778.1-nm ac Stark shift {[}2.30(4) x 10(-13)(mW/mm(2))(-1)] that is in good agreement with our measured value of 2.5(2) x 10(-13)(mW/mm(2))(-1). We include a calculation of the temperature-dependent blackbody radiation (BBR) shift, and we predict that the clock could be operated either with zero net BBR shift {[}T = 495.9(27) K] or with zero first-order sensitivity {[}T = 368.1(14) K]. Also described is the calculation of the dc Stark shift of 5.5(1) x 10(-15)/(V/cm(2)) as well as clock sensitivities to optical alignment variations in both a cat{\textquoteright}s eye and a flat mirror retroreflector. Finally, we characterize these Stark effects, discussing mitigation techniques necessary to reduce final clock instabilities.},
issn = {2469-9926},
doi = {10.1103/PhysRevA.100.023417},
author = {Martin, Kyle W. and Stuhl, Benjamin and Eugenio, Jon and Safronova, Marianna S. and Phelps, Gretchen and Burke, John H. and Lemke, Nathan D.}
}
@article {ISI:000461126600036,
title = {Optical clock comparison for Lorentz symmetry testing},
journal = {Nature},
volume = {567},
number = {7747},
year = {2019},
month = {MAR 14},
pages = {204+},
publisher = {NATURE PUBLISHING GROUP},
type = {Article},
abstract = {Questioning basic assumptions about the structure of space and time has greatly enhanced our understanding of nature. State-of-the-art atomic clocks(1-3) make it possible to precisely test fundamental symmetry properties of spacetime and search for physics beyond the standard model at low energies of just a few electronvolts(4). Modern tests of Einstein{\textquoteright}s theory of relativity try to measure so-far-undetected violations of Lorentz symmetry(5); accurately comparing the frequencies of optical clocks is a promising route to further improving such tests(6). Here we experimentally demonstrate agreement between two single-ion optical clocks at the 10(-18) level, directly validating their uncertainty budgets, over a six-month comparison period. The ytterbium ions of the two clocks are confined in separate ion traps with quantization axes aligned along non-parallel directions. Hypothetical Lorentz symmetry violations(5-7) would lead to periodic modulations of the frequency offset as the Earth rotates and orbits the Sun. From the absence of such modulations at the 10(-19) level we deduce stringent limits of the order of 10(-21) on Lorentz symmetry violation parameters for electrons, improving previous limits(8-10) by two orders of magnitude. Such levels of precision will be essential for low-energy tests of future quantum gravity theories describing dynamics at the Planck scale(4), which are expected to predict the magnitude of residual symmetry violations.},
issn = {0028-0836},
doi = {10.1038/s41586-019-0972-2},
author = {Sanner, Christian and Huntemann, Nils and Lange, Richard and Tamm, Christian and Peik, Ekkehard and Safronova, Marianna S. and Porsev, Sergey G.}
}
@article {ISI:000471993700016,
title = {The Search for Variation of Fundamental Constants with Clocks},
journal = {Ann. Phys.-Berlin},
volume = {531},
number = {5, SI},
year = {2019},
month = {MAY},
pages = {1800364},
publisher = {WILEY-V C H VERLAG GMBH},
type = {Article},
abstract = {In many theories beyond the Standard Model the quantities that we call {\textquoteleft}{\textquoteleft}fundamental constants{{\textquoteright}{\textquoteright}} become space-time dependent, leading to corresponding variation of atomic and molecular spectra and clock frequencies. The extraordinary improvement of the atomic clock precision in the past fifteen years enabled testing the constancy of the fundamental constant at a very high level of precision. Herein, searches for the variation of fundamental constants with clocks are discussed, focusing on recent key results and future proposals, including highly charged ion, molecular, and nuclear clocks. The relevance of the recent searches for oscillatory and transient variation of fundamental constants to the major unexplained phenomena of our Universe, the nature of dark matter, is discussed.},
keywords = {atomic clocks, highly charged ions, nuclear clock, variation of fundamental constants},
issn = {0003-3804},
doi = {10.1002/andp.201800364},
author = {Safronova, Marianna S.}
}
@article { ISI:000454636100002,
title = {Alkaline-Earth Atoms in Optical Tweezers},
journal = {PHYSICAL REVIEW X},
volume = {8},
number = {4},
year = {2018},
month = {DEC 28},
pages = {041055},
abstract = {We demonstrate single-shot imaging and narrow-line cooling of individual alkaline-earth atoms in optical tweezers; specifically, strontium trapped in 515.2-nm light. Our approach enables high-fidelity detection of single atoms by imaging photons from the broad singlet transition while cooling on the narrow intercombination line, and we extend this technique to highly uniform two-dimensional tweezer arrays with 121 sites. Cooling during imaging is based on a previously unobserved narrow-line Sisyphus mechanism, which we predict to be applicable in a wide variety of experimental situations. Further, we demonstrate optically resolved sideband cooling of a single atom to near the motional ground state of a tweezer, which is tuned to a magic-trapping configuration achieved by elliptical polarization. Finally, we present calculations, in agreement with our experimental results, that predict a linear-polarization and polarization-independent magic crossing at 520(2) nm and 500.65(50) nm, respectively. Our results pave the way for a wide range of novel experimental avenues based on individually controlled alkaline-earth atoms in tweezers-from fundamental experiments in atomic physics to quantum computing, simulation, and metrology.},
keywords = {Atomic and molecular physics, Quantum Information, Quantum Physics},
issn = {2160-3308},
doi = {10.1103/PhysRevX.8.041055},
author = {Cooper, Alexandre and Covey, Jacob P. and Madjarov, Ivaylo S. and Porsev, Sergey G. and Safronova, Marianna S. and Endres, Manuel}
}
@article { ISI:000432974400003,
title = {Two Clock Transitions in Neutral Yb for the Highest Sensitivity to Variations of the Fine-Structure Constant},
journal = {PHYSICAL REVIEW LETTERS},
volume = {120},
number = {17},
year = {2018},
month = {APR 27},
pages = {173001},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.120.173001},
author = {Safronova, Marianna S. and Porsev, Sergey G. and Sanner, Christan and Ye, Jun}
}
@article { ISI:000411773400029,
title = {Visible spectra of highly charged holmium ions observed with a compact electron beam ion trap},
journal = {NUCLEAR INSTRUMENTS \& METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS},
volume = {408},
year = {2017},
note = {18th International Conference on the Physics of Highly Charged Ions (HCI), Jan Kochanowski Univ, Kielce, POLAND, SEP 11-16, 2016},
month = {OCT 1},
pages = {118-121},
issn = {0168-583X},
doi = {10.1016/j.nimb.2017.03.135},
author = {Nakajima, Takayuki and Okada, Kunihiro and Wada, Michiharu and Dzuba, Vladimir A. and Safronova, Marianna S. and Safronova, Ulyana I. and Ohmae, Noriaki and Katori, Hidetoshi and Nakamura, Nobuyuki}
}
@article {2555,
title = {Blackbody Radiation Shifts in Optical Atomic Clocks},
journal = {IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL},
volume = {59},
year = {2012},
month = {MAR},
pages = {439-447},
issn = {0885-3010},
doi = {10.1109/TUFFC.2012.2213},
author = {Safronova, Marianna S. and Kozlov, Mikhail G. and Clark, Charles W.}
}