arXiv subjects

Marianna S. Safronova

Publications and source records attributed to Marianna S. Safronova.

At least 37 records · Page 2Linked to original sources

arXiv2024

A clock with $8\times10^{-19}$ systematic uncertainty

We report an optical lattice clock with a total systematic uncertainty of $8.1 \times 10^{-19}$ in fractional frequency units, representing the lowest uncertainty of any clock to date. The clock relies on interrogating the ultra-narrow ${}^1S_0 \rightarrow {}^3P_0$ transition in a dilute ensemble of fermionic strontium atoms trapped in a vertically-oriented, shallow, one-dimensional optical lattice. Using imaging spectroscopy, we previously demonstrated record high atomic coherence time and measurement precision enabled by precise control of collisional shifts and the lattice light shift. In this work, we revise the black body radiation shift correction by evaluating the $5s4d$ $^3D_1$ lifetime, necessitating precise characterization and control of many body effects in the $5s4d$ $^3D_1$ decay. Lastly, we measure the second order Zeeman coefficient on the least magnetically sensitive clock transition. All other systematic effects have uncertainties below $1 \times 10^{-19}$.

physics.atom-ph↗

arXiv2024

Prospects of a thousand-ion Sn$^{2+}$ Coulomb-crystal clock with sub-$10^{-19}$ inaccuracy

We propose a many-ion optical atomic clock based on three-dimensional Coulomb crystals of order one thousand Sn$^{2+}$ ions confined in a linear RF Paul trap. Sn$^{2+}$ has a unique combination of features that is not available in previously considered ions: a $^1$S$_0$ $\leftrightarrow$ $^3$P$_0$ clock transition between two states with zero electronic and nuclear angular momentum (I = J = F = 0) making it immune to nonscalar perturbations, a negative differential polarizability making it possible to operate the trap in a manner such that the two dominant shifts for three-dimensional ion crystals cancel each other, and a laser-accessible transition suitable for direct laser cooling and state readout. We present calculations of the differential polarizability, other relevant atomic properties, and the motion of ions in large Coulomb crystals, in order to estimate the achievable accuracy and precision of Sn$^{2+}$ Coulomb-crystal clocks.

physics.atom-ph↗

arXiv2023

Quantum Sensors for High Energy Physics

Strong motivation for investing in quantum sensing arises from the need to investigate phenomena that are very weakly coupled to the matter and fields well described by the Standard Model. These can be related to the problems of dark matter, dark sectors not necessarily related to dark matter (for example sterile neutrinos), dark energy and gravity, fundamental constants, and problems with the Standard Model itself including the Strong CP problem in QCD. Resulting experimental needs typically involve the measurement of very low energy impulses or low power periodic signals that are normally buried under large backgrounds. This report documents the findings of the 2023 Quantum Sensors for High Energy Physics workshop which identified enabling quantum information science technologies that could be utilized in future particle physics experiments, targeting high energy physics science goals.

hep-ex↗

arXiv2023

Enhancing Divalent Optical Atomic Clocks with the $^{1}\mathrm{S}_0$$\leftrightarrow$$^{3}\mathrm{P}_{2}$ Transition

Divalent atoms and ions with a singlet $S$ ground state and triplet $P$ excited state form the basis of many high-precision optical atomic clocks. Along with the metastable $^{3}\mathrm{P}_{0}$ clock state, these atomic systems also have a nearby metastable $^{3}\mathrm{P}_{2}$ state. We investigate the properties of the electric quadrupole $^{1}\mathrm{S}_0$$\leftrightarrow$$^{3}\mathrm{P}_{2}$ transition with a focus on enhancing already existing optical atomic clocks. In particular, we investigate the $^{1}\mathrm{S}_0$$\leftrightarrow$$^{3}\mathrm{P}_{2}$ transition in $^{27}\mathrm{Al}^{+}$ and calculate the differential polarizability, hyperfine effects, and other relevant atomic properties. We also discuss potential applications of this transition, notably that it provides two transitions with different sensitivities to systematic effects in the same species. In addition, we describe how the $^{1}\mathrm{S}_0$$\leftrightarrow$$^{3}\mathrm{P}_{2}$ transition can be used to search for physics beyond the Standard Model and motivate investigation of this transition in other existing optical atomic clocks.

physics.atom-ph↗

arXiv2023

Motional ground-state cooling of single atoms in state-dependent optical tweezers

Laser cooling of single atoms in optical tweezers is a prerequisite for neutral atom quantum computing and simulation. Resolved sideband cooling comprises a well-established method for efficient motional ground-state preparation, but typically requires careful cancellation of light shifts in so-called magic traps. Here, we study a novel laser cooling scheme which overcomes such constraints, and applies when the ground-state of a narrow cooling transition is trapped stronger than the excited state. We demonstrate our scheme, which exploits sequential addressing of red sideband transitions via frequency chirping of the cooling light, at the example of $^{88}$Sr atoms, and report ground-state populations compatible with recent experiments in magic tweezers. The scheme also induces light-assisted collisions, which are key to the assembly of large atom arrays. Our work enriches the toolbox for tweezer-based quantum technology, also enabling applications for tweezer-trapped molecules and ions that are incompatible with resolved sideband cooling conditions.

physics.atom-ph↗

arXiv2023

Detection of Bosenovae with Quantum Sensors on Earth and in Space

In a broad class of theories, the accumulation of ultralight dark matter (ULDM) with particles of mass $10^{-22}~\textrm{eV} < m_ϕ < 1~\textrm{eV}$ leads the to formation of long-lived bound states known as boson stars. When the ULDM exhibits self-interactions, prodigious bursts of energy carried by relativistic bosons are released from collapsing boson stars in bosenova explosions. We extensively explore the potential reach of terrestrial and space-based experiments for detecting transient signatures of emitted relativistic bursts of scalar particles, including ULDM coupled to photons, electrons, and gluons, capturing a wide range of motivated theories. For the scenario of relaxion ULDM, we demonstrate that upcoming experiments and technology such as nuclear clocks as well as space-based interferometers will be able to sensitively probe orders of magnitude in the ULDM coupling-mass parameter space, challenging to study otherwise, by detecting signatures of transient bosenova events. Our analysis can be readily extended to different scenarios of relativistic scalar particle emission.

hep-ph↗

arXiv2023

Optical Telecommunications-Band Clock based on Neutral Titanium Atoms

We propose an optical clock based on narrow, spin-forbidden M1 and E2 transitions in laser-cooled neutral titanium. These transitions exhibit much smaller black body radiation shifts than those in alkaline earth atoms, small quadratic Zeeman shifts, and have wavelengths in the S, C, and L-bands of fiber-optic telecommunication standards, allowing for integration with robust laser technology. We calculate lifetimes; transition matrix elements; dynamic scalar, vector, and tensor polarizabilities; and black body radiation shifts of the clock transitions using a high-precision relativistic hybrid method that combines a configuration interaction and coupled cluster approaches. We also calculate the line strengths and branching ratios of the transitions used for laser cooling. To identify magic trapping wavelengths, we have completed the largest-to-date direct dynamical polarizability calculations. Finally, we identify new challenges that arise in precision measurements due to magnetic dipole-dipole interactions and describe an approach to overcome them. Direct access to a telecommunications-band atomic frequency standard will aid the deployment of optical clock networks and clock comparisons over long distances.

physics.atom-ph↗

arXiv2022

A Portal for High-Precision Atomic Data and Computation: Design and Best Practices

The Atom portal, udel.edu/atom, provides the scientific community with easily accessible high-quality data about properties of atoms and ions, such as energies, transition matrix elements, transition rates, radiative lifetimes, branching ratios, polarizabilities, and hyperfine constants. The data are calculated using a high-precision state-of-the-art linearized coupled-cluster method, high-precision experimental values are used where available. All values include estimated uncertainties. Where available, experimental results are provided with references. This paper provides an overview of the portal and describes the design as well as applied software engineering practices.

physics.atom-ph↗

arXiv2022

New Measurement Resolves Key Astrophysical Fe XVII Oscillator Strength Problem

One of the most enduring and intensively studied problems of X-ray astronomy is the disagreement of state-of-the art theory and observations for the intensity ratio of two Fe XVII transitions of crucial value for plasma diagnostics, dubbed 3C and 3D. We unravel this conundrum at the PETRA III synchrotron facility by increasing the resolving power two and a half times and the signal-to-noise ratio thousand-fold compared to our previous work. The Lorentzian wings had hitherto been indistinguishable from the background and were thus not modeled, resulting in a biased line-strength estimation. The present experimental oscillator-strength ratio $R_\mathrm{exp}=f_{\mathrm{3C}}/f_{\mathrm{3D}}=3.51(2)_{\mathrm{stat}}(7)_{\mathrm{sys}}$ agrees with our state-of-the-art calculation of $R_\mathrm{th}=3.55(2)$, as well as with some previous theoretical predictions. To further rule out any uncertainties associated with the measured ratio, we also determined the individual natural linewidths and oscillator strengths of 3C and 3D transitions, which also agree well with the theory. This finally resolves the decades-old mystery of Fe XVII oscillator strengths.

physics.atom-ph↗

arXiv2022

New Constraints on Dark Matter and Cosmic Neutrino Profiles through Gravity

We derive purely gravitational constraints on dark matter and cosmic neutrino profiles in the solar system using asteroid (101955) Bennu. We focus on Bennu because of its extensive tracking data and high-fidelity trajectory modeling resulting from the OSIRIS-REx mission. We find that the local density of dark matter is bound by $ρ_{\rm DM}\lesssim 3.3\times 10^{-15}\;\rm kg/m^3 \simeq 6\times10^6\,\barρ_{\rm DM}$, in the vicinity of $\sim 1.1$ au (where $\barρ_{\rm DM}\simeq 0.3\;\rm GeV/cm^3$). We show that high-precision tracking data of solar system objects can constrain cosmic neutrino overdensities relative to the Standard Model prediction $\bar{n}_ν$, at the level of $η\equiv n_ν/\bar{n}_ν\lesssim 1.7 \times 10^{11}(0.1 \;{\rm eV}/m_ν)$ (Saturn), comparable to the existing bounds from KATRIN and other previous laboratory experiments (with $m_ν$ the neutrino mass). These local bounds have interesting implications for existing and future direct-detection experiments. Our constraints apply to all dark matter candidates but are particularly meaningful for scenarios including solar halos, stellar basins, and axion miniclusters, which predict or allow overdensities in the solar system. Furthermore, introducing a DM-SM long-range fifth force with a strength $\tildeα_D$ times stronger than gravity, Bennu can set a constraint on $ρ_{\rm DM}\lesssim \barρ_{\rm DM}\left(6 \times 10^6/\tildeα_D\right)$. These constraints can be improved in the future as the accuracy of tracking data improves, observational arcs increase, and more missions visit asteroids.

hep-ph↗

arXiv2022

Snowmass 2021: Quantum Sensors for HEP Science -- Interferometers, Mechanics, Traps, and Clocks

A wide range of quantum sensing technologies are rapidly being integrated into the experimental portfolio of the high energy physics community. Here we focus on sensing with atomic interferometers; mechanical devices read out with optical or microwave fields; precision spectroscopic methods with atomic, nuclear, and molecular systems; and trapped atoms and ions. We give a variety of detection targets relevant to particle physics for which these systems are uniquely poised to contribute. This includes experiments at the precision frontier like measurements of the electron dipole moment and electromagnetic fine structure constant and searches for fifth forces and modifications of Newton's law of gravity at micron-to-millimeter scales. It also includes experiments relevant to the cosmic frontier, especially searches for gravitional waves and a wide variety of dark matter candidates spanning heavy, WIMP-scale, light, and ultra-light mass ranges. We emphasize here the need for more developments both in sensor technology and integration into the broader particle physics community.

quant-ph↗

arXiv2022

Magic wavelengths of the Sr ($5s^2\;^1\!S_0$--$5s5p\;^3\!P_1$) intercombination transition near the $5s5p\;^3\!P_1$--$5p^2\;^3\!P_2$ transition

Predicting magic wavelengths accurately requires precise knowledge of electric-dipole matrix elements of nearby atomic transitions. As a result, measurements of magic wavelengths allow us to test theoretical predictions for the matrix elements that frequently can not be probed by any other methods. Here, we calculate and measure a magic wavelength near $473$ nm of the $5s^2\,^1\!S_0 - 5s5p\,^3\!P_1$ intercombination transition of ${}^{88}$Sr. Experimentally, we find $473.361(4)$ nm for $Δm=0$ ($π$ transition) and $473.133(14)$ nm for $Δm=-1$ ($σ^{-}$ transition). Theoretical calculations yield $473.375(22)$~nm and $473.145(20)$ nm, respectively. The $^3\!P_1$ polarizability is dominated by the contributions to the $5p^2\, ^3\!P$ levels and excellent agreement of theory and experiment validates both theoretical values of these matrix elements and estimates of their uncertainties.

physics.atom-ph↗

arXiv2021

Fundamental Physics with a State-of-the-Art Optical Clock in Space

Recent advances in optical atomic clocks and optical time transfer have enabled new possibilities in precision metrology for both tests of fundamental physics and timing applications. Here we describe a space mission concept that would place a state-of-the-art optical atomic clock in an eccentric orbit around Earth. A high stability laser link would connect the relative time, range, and velocity of the orbiting spacecraft to earthbound stations. The primary goal for this mission would be to test the gravitational redshift, a classical test of general relativity, with a sensitivity 30,000 times beyond current limits. Additional science objectives include other tests of relativity, enhanced searches for dark matter and drifts in fundamental constants, and establishing a high accuracy international time/geodesic reference.

gr-qc↗

arXiv2021

SpaceQ -- Direct Detection of Ultralight Dark Matter with Space Quantum Sensors

Recent advances in quantum sensors, including atomic clocks, enable searches for a broad range of dark matter candidates. The question of the dark matter distribution in the Solar system critically affects the reach of dark matter direct detection experiments. Partly motivated by the NASA Deep Space Atomic Clock (DSAC), we show that space quantum sensors present new opportunities for ultralight dark matter searches, especially for dark matter states bound to the Sun. We show that space quantum sensors can probe unexplored parameter space of ultralight dark matter, covering theoretical relaxion targets motivated by naturalness and Higgs mixing. If an atomic clock were able to make measurements on the interior of the solar system, it could probe this highly sensitive region directly and set very strong constraints on the existence of such a bound-state halo in our solar system. We present sensitivity projections for space-based probes of ultralight dark matter which couples to electron, photon, and gluon fields, based on current and future atomic, molecular, and nuclear clocks.

hep-ph↗

arXiv2020

Probing the Relaxed Relaxion at the Luminosity and Precision Frontiers

Cosmological relaxation of the electroweak scale is an attractive scenario addressing the gauge hierarchy problem. Its main actor, the 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'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.

hep-ph↗

arXiv2020

High Resolution Photoexcitation Measurements Exacerbate the Long-Standing Fe XVII Oscillator Strength Problem

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.

physics.atom-ph↗

arXiv2020

Detection of missing low-lying atomic states in actinium

Two lowest-energy odd-parity atomic levels of actinium, 7s^27p 2P^o_1/2, 7s^27p 2P^o_3/2, were observed via two-step resonant laser-ionization spectroscopy and their respective energies were measured to be 7477.36(4) cm^-1 and 12 276.59(2) cm^-1. The lifetimes of these states were determined as 668(11) ns and 255(7) ns, respectively. In addition, these properties were calculated using a hybrid approach that combines configuration interaction and coupled-cluster methods in good agreement. 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 medicalisotope production and future fundamental physics experiments with this atom.

physics.atom-ph↗

arXiv2019

Combining experiments and relativistic theory for establishing accurate radiative quantities in atoms: the lifetime of the $^2$P$_{3/2}$ state in $^{40}$Ca$^+$

We report a precise determination of the lifetime of the (4p)$^2$P$_{3/2}$ state of $^{40}$Ca$^+$, $τ_{\textrm{P}_{3/2}}=6.639(42)$ 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 [Safronova et al., PRA 83, 012503 (2011)], but a 6-$σ$ discrepancy with the most precise previous experimental value, $6.924(19)$ ns [Jin et al., PRL 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.

physics.atom-ph↗