B. M. Roberts
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View article: Atomic Observables Induced by Cosmic Fields
Atomic Observables Induced by Cosmic Fields Open
The existence of cosmic fields made from yet unknown light bosons is predicted in many extensions to the Standard Model. They are especially of interest as possible constituents of dark matter. To detect such light and weakly interacting f…
View article: Theoretical characterization of the barium ii and radium ii ions
Theoretical characterization of the barium ii and radium ii ions Open
Motivated by recent experimental advances, including the ongoing development of an optical atomic clock in singly ionised radium, we perform a detailed theoretical characterisation of Ra+ and its lighter analogue, Ba+. Both ions are of int…
View article: Ultralight Dark Matter Search with Space-Time Separated Atomic Clocks and Cavities
Ultralight Dark Matter Search with Space-Time Separated Atomic Clocks and Cavities Open
We devise and demonstrate a method to search for nongravitational couplings of ultralight dark matter to standard model particles using space-time separated atomic clocks and cavity-stabilized lasers. By making use of space-time separated …
View article: Vacuum polarization corrections to hyperfine structure in many-electron atoms
Vacuum polarization corrections to hyperfine structure in many-electron atoms Open
We perform a theoretical study of vacuum polarization corrections to the hyperfine structure in many-electron atoms. Calculations are performed for systems of interest for precision atomic tests of fundamental physics belonging to the alka…
View article: Ultralight Dark Matter Search with Space-Time Separated Atomic Clocks and Cavities
Ultralight Dark Matter Search with Space-Time Separated Atomic Clocks and Cavities Open
We devise and demonstrate a method to search for non-gravitational couplings of ultralight dark matter to standard model particles using space-time separated atomic clocks and cavity-stabilized lasers. By making use of space-time separated…
View article: Accurate electron-recoil ionization factors for dark matter direct detection in xenon, krypton, and argon
Accurate electron-recoil ionization factors for dark matter direct detection in xenon, krypton, and argon Open
While most scintillation-based dark matter experiments search for weakly interacting massive particles (WIMPs), a sub-GeV WIMP-like particle may also be detectable in these experiments. While dark matter of this type and scale would not le…
View article: Accurate electron-recoil ionization factors for dark matter direct detection in xenon, krypton and argon
Accurate electron-recoil ionization factors for dark matter direct detection in xenon, krypton and argon Open
While most scintillation-based dark matter experiments search for Weakly Interacting Massive Particles (WIMPs), a sub-GeV WIMP-like particle may also be detectable in these experiments. While dark matter of this type and scale would not le…
View article: QED radiative corrections to electric dipole amplitudes in heavy atoms
QED radiative corrections to electric dipole amplitudes in heavy atoms Open
We use the radiative potential method to perform a detailed study of quantum electrodynamics (QED) radiative corrections to electric dipole (E1) transition amplitudes in heavy alkali-metal atoms Rb, Cs, Fr, and alkali-metal-like ions Sr+, …
View article: Experimental and theoretical study of dynamic polarizabilities in the $5S_{1/2}$-$5D_{5/2}$ clock transition in rubidium-87 and determination of E1 matrix elements
Experimental and theoretical study of dynamic polarizabilities in the $5S_{1/2}$-$5D_{5/2}$ clock transition in rubidium-87 and determination of E1 matrix elements Open
The interaction between light and an atom causes perturbations in the atom's energy levels, known as the light-shift. These light-shifts are a key source of inaccuracy in atomic clocks, and can also deteriorate their precision. We present …
View article: Electric dipole transition amplitudes for atoms and ions with one valence electron
Electric dipole transition amplitudes for atoms and ions with one valence electron Open
Motivated by recent measurements for several alkali-metal atoms and alkali-metal-like ions, we perform a detailed study of electric dipole (E1) transition amplitudes in K, Ca+, Rb, Sr+, Cs, Ba+, Fr, and Ra+, which are of interest for studi…
View article: Bohr-Weisskopf effect: From hydrogenlike-ion experiments to heavy-atom calculations of the hyperfine structure
Bohr-Weisskopf effect: From hydrogenlike-ion experiments to heavy-atom calculations of the hyperfine structure Open
In this paper we study the influence of electron screening on the\nBohr-Weisskopf (BW) effect in many-electron atoms. The BW effect gives the\nfinite-nucleus magnetization contribution to the hyperfine structure.\nRelativistic atomic many-…
View article: Comment on “New physics constraints from atomic parity violation in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Cs</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>133</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>”
Comment on “New physics constraints from atomic parity violation in ” Open
In a recent Letter [B. K. Sahoo, B. P. Das, and H. Spiesberger, Phys. Rev. D\n103, L111303 (2021)], a calculation of the parity violating 6S-7S E1 amplitude\nin Cs is reported, claiming an uncertainty of just 0.3%. In this Comment, we\npoi…
View article: Comment on "New physics constraints from atomic parity violation in 133-Cs"
Comment on "New physics constraints from atomic parity violation in 133-Cs" Open
In a recent Letter [B. K. Sahoo, B. P. Das, and H. Spiesberger, Phys. Rev. D 103, L111303 (2021)], a calculation of the parity violating 6S-7S E1 amplitude in Cs is reported, claiming an uncertainty of just 0.3%. In this Comment, we point …
View article: Hyperfine anomaly in heavy atoms and its role in precision atomic searches for new physics
Hyperfine anomaly in heavy atoms and its role in precision atomic searches for new physics Open
We report on our calculations of differential hyperfine anomalies in the\nnuclear single-particle model for a number of atoms and ions of interest for\nstudies of fundamental symmetries violations. Comparison with available\nexperimental d…
View article: Searching for Dark Matter with an Optical Cavity and an Unequal-Delay Interferometer
Searching for Dark Matter with an Optical Cavity and an Unequal-Delay Interferometer Open
We propose a new type of experiment that compares the frequency of a clock (an ultrastable optical cavity in this case) at time t to its own frequency some time t-T earlier, by "storing" the output signal (photons) in a fiber delay line. I…
View article: Nuclear Magnetic Moments of Francium-207–213 from Precision Hyperfine Comparisons
Nuclear Magnetic Moments of Francium-207–213 from Precision Hyperfine Comparisons Open
We report a fourfold improvement in the determination of nuclear magnetic moments for neutron-deficient francium isotopes 207-213, reducing the uncertainties from 2% for most isotopes to 0.5%. These are found by comparing our high-precisio…
View article: Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks
Search for transient variations of the fine structure constant and dark matter using fiber-linked optical atomic clocks Open
We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network…
View article: Searching for DArk Matter with a Non-Equal Delay inteferometer: The DAMNED experiment
Searching for DArk Matter with a Non-Equal Delay inteferometer: The DAMNED experiment Open
We report an experiment that compares the frequency of a clock (an ultra-stable optical cavity in this case) at time $t$ to its own frequency some time $t-T$ earlier, by storing the output signal (photons) in a fibre delay line. In ultra-l…
View article: Erratum: Calculations of the atomic structure for the low-lying states of actinium [Phys. Rev. A <b>100</b>, 022504 (2019)]
Erratum: Calculations of the atomic structure for the low-lying states of actinium [Phys. Rev. A <b>100</b>, 022504 (2019)] Open
Received 17 April 2020DOI:https://doi.org/10.1103/PhysRevA.101.059901©2020 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasAtomic & molecular structureAtomic spectraElectron correlation calculations for atoms & ionsE…
View article: Search for a Variation of the Fine Structure Constant around the Supermassive Black Hole in Our Galactic Center
Search for a Variation of the Fine Structure Constant around the Supermassive Black Hole in Our Galactic Center Open
Searching for space-time variations of the constants of Nature is a promising way to search for new physics beyond general relativity and the standard model motivated by unification theories and models of dark matter and dark energy. We pr…
View article: Low-Cost Microfabrication Tool Box.
Low-Cost Microfabrication Tool Box. Open
Microsystems are key enabling technologies, with applications found in almost every industrial field, including in vitro diagnostic, energy harvesting, automotive, telecommunication, drug screening, etc. Microsystems, such as microsensors …
View article: Low-Cost Microfabrication Tool Box
Low-Cost Microfabrication Tool Box Open
Microsystems are key enabling technologies, with applications found in almost every industrial field, including in vitro diagnostic, energy harvesting, automotive, telecommunication, drug screening, etc. Microsystems, such as microsensors …
View article: Correlation trends in the hyperfine structure for Rb, Cs, and Fr, and high-accuracy predictions for hyperfine constants
Correlation trends in the hyperfine structure for Rb, Cs, and Fr, and high-accuracy predictions for hyperfine constants Open
We have performed high-precision calculations of the hyperfine structure for n 2S_1/2 and n 2P_1/2 states of the alkali-metal atoms Rb, Cs, and Fr across principal quantum number n, and studied the trend in the size of the correlations. Ou…
View article: Electron-interacting dark matter: Implications from DAMA/LIBRA-phase2 and prospects for liquid xenon detectors and NaI detectors
Electron-interacting dark matter: Implications from DAMA/LIBRA-phase2 and prospects for liquid xenon detectors and NaI detectors Open
We investigate the possibility for the direct detection of low mass (GeV scale) WIMP dark matter in scintillation experiments. Such WIMPs are typically too light to leave appreciable nuclear recoils, but may be detected via their scatterin…
View article: Calculations of the atomic structure for the low-lying states of actinium
Calculations of the atomic structure for the low-lying states of actinium Open
We employ a technique that combines the configuration interaction method with\nthe singles-doubles coupled-cluster method to perform calculation of the energy\nlevels, transition amplitudes, lifetimes, g-factors, and magnetic dipole and\ne…
View article: Search for transient variations of the fine structure constant and dark\n matter using fiber-linked optical atomic clocks
Search for transient variations of the fine structure constant and dark\n matter using fiber-linked optical atomic clocks Open
We search for transient variations of the fine structure constant using data\nfrom a European network of fiber-linked optical atomic clocks. By searching for\ncoherent variations in the recorded clock frequency comparisons across the\nnetw…
View article: Violation of the equivalence principle from light scalar fields: from\n Dark Matter candidates to scalarized black holes
Violation of the equivalence principle from light scalar fields: from\n Dark Matter candidates to scalarized black holes Open
Tensor-scalar theory is a wide class of alternative theory of gravitation\nthat can be motivated by higher dimensional theories, by models of dark matter\nor dark ernergy. In the general case, the scalar field will couple\nnon-universally …
View article: Violation of the equivalence principle from light scalar fields: from Dark Matter candidates to scalarized black holes
Violation of the equivalence principle from light scalar fields: from Dark Matter candidates to scalarized black holes Open
Tensor-scalar theory is a wide class of alternative theory of gravitation that can be motivated by higher dimensional theories, by models of dark matter or dark ernergy. In the general case, the scalar field will couple non-universally to …
View article: Electron-interacting dark matter and implications from DAMA/LIBRA-phase2
Electron-interacting dark matter and implications from DAMA/LIBRA-phase2 Open
We investigate the possibility for the direct detection of low mass (GeV scale) WIMP dark matter in scintillation experiments. Such WIMPs are typically too light to leave appreciable nuclear recoils, but may be detected via their scatterin…
View article: Novel approaches to dark-matter detection using space-time separated clocks
Novel approaches to dark-matter detection using space-time separated clocks Open
We discuss the theoretical analysis and interpretation of space-time separated clock experiments in the context of a space-time varying scalar field that is non-universally coupled to the standard model fields. If massive, such a field is …