Search

YbOH molecule is one of the most sensitive systems for the electron electric dipole moment ($e$EDM) searches. Zeeman splittings of the $e$EDM sensitive levels have significant implications to control and suppress important systematic effects due to stray magnetic field in experiments for $e$EDM searches. The electric-field-dependent g factors of the lowest rotational level of the first excited bending vibrational mode of $^{174}$YbOH are calculated. l-doublet levels with small g factors difference are found and main contributions to the difference are determined.

Observations of the rotational spectrum of lead monofluoride, PbF, have been extended up to transitions in the \textit{v} = 7 level for $^{208}$PbF in the lowest $X_1\,^2\Pi_{1/2}$ state of the radical and \textit{v} = 5 for the $^{207}$Pb and $^{206}$Pb isotopologues. The data also include a few measurements for $^{204}$PbF in \textit{v} = 0. These new measurements have been combined with existing near-IR measurements of the $X_2 - X_1$ fine-structure transition and a simultaneous multi-isotope fit of the data to an effective isotope-independent ro-vibronic Hamiltonian has been carried out. The resulting parameters fully characterize the vibrational, rotational and hyperfine structure of the combined $X_1 \, / \, X_2$ state of the radical. A pair of opposite parity levels with total angular momentum quantum number, $F=1/2$, in the lowest rotational level, $J=1/2$ of \PbF \,are close in energy and their spacing decreases with vibrational excitation. The experimental results show the spacing decreases to less than 20 MHz at $v=7$ and 8. The experimental work is complemented by new \textit{ab initio} calculations which support the results and allow predictions outside the experimental data range. The calculated radiative lifetimes of the relevant vibrationally excited states are of the order of 50 ms. This work was motivated by interest in using \PbF\, as a vehicle for future probes of the standard model of physics such as placing limits on the electron's electric dipole moment (\eEDM), molecular charge-parity non-conservation and Born-Oppenheimer breakdown effects for example., Comment: 36 pages, 4 figures, 5 page Appendix. Accepted by Phys FRev A, 2024-09-04

Chemical interface damping is a change in the effective collision frequency of conduction band electrons in metal originating from a chemical change of the metal interface. In this work, we present in-situ ellipsometric measurements that reveal the chemical interface damping effect from electrochemical oxidation of single crystal and polycrystalline gold films. We observe an increase in collision frequency of up to 21 meV for single-crystalline gold. To compare to results obtained with thiols and metal-oxides on gold nanoparticles, we normalize the collision frequency by the electron mean free path to the surface of the structure. We show that electrochemical gold oxidation provides a stronger effect on collision frequency than these coatings. Similar ellipsometric experiments have previously been conducted to investigate the optical properties of gold oxide, but without taking chemical interface damping into account. The change in reflection from oxidation of gold was solely attributed to the oxide coating. We also show that the chemical interface damping effect saturates at a larger effective oxide thickness, which is attributed to the stabilization of the gold-oxide interface.

The generation and utilization of hot charge carriers in plasmonic materials have emerged as a topic of significant importance, with profound implications across multiple disciplines, including optoelectronics, photovoltaics, photocatalysis, and sensing. In this study, we investigate the hot electron transfer from nanoporous gold (npAu) in dependence of the structure size, utilizing both the nanoscale feature size and the interconnected nature of this material. We employ photoelectron injection from nanoporous gold into the electrolyte under UV illumination as a test electron transfer process. Nanoporous gold thin films with sub-10 nm initial ligament diameter are stepwise coarsened by potential cycles in a photoelectrochemical setup, thereby allowing us to precisely probe the influence of ligament diameter on the photocurrent response. The resulting ligament diameter variations are confirmed by scanning electron microscopy (SEM) analysis. As the ligament diameter increased from 8 to 16 nm, there was a corresponding decrease in quantum efficiency proportional to the inverse ligament diameter squared. Such dependency is expected for electrons excited by surface collisions. For the small ligament diameter of 10 nm we estimate an emission efficiency of excited 6sp electrons as 3.14%, reaching 23% for the surface excited electrons., Comment: 30 pages, 13 figures

We investigate the process of photon absorption by atoms or molecules shortly interacting with a laser beam in the dipole approximation. Assuming that the interaction time $\tau$ is much smaller than the lifetime of the corresponding excited state, we examine the absorption probability as a function of $\tau$. Besides, we incorporate Doppler broadening due to nonzero temperature of the atoms (molecules). It is demonstrated that in the case of a zero detuning and without Doppler broadening, the absorption probability is quadratic in $\tau$. Once Doppler broadening is taken into account or the laser beam is off from the resonant frequency, the absorption probability becomes linear in $\tau$. Our findings are expected to be important for experimental studies in optical cells or cavities where atoms or molecules traverse continuous laser beams. The experimental prospects of searching for the electric dipole moment (EDM) of the electron are discussed in detail.

YbOH molecule is one of the most sensitive systems for the electron electric dipole moment ($e$EDM) searches. The $e$EDM-induced energy shift is proportional to polarization ($P$) of the molecule. In Ref. [A. Petrov and A. Zakharova, Phys. Rev. A 105, L050801 (2022)] was shown that the value of l-doubling and spin-rotation splitting directly influences the maximum value of $P$. Recently in Ref. [Jadbabaie, Y. Takahashi, N. H. Pilgram, C. J. Conn, Y. Zeng, C. Zhang, and N. R. Hutzler, New Journal of Physics 25, 073014 (2023)] the corresponding energy levels was determined experimentally. We introduced electronic matrix elements in Hund's case $c$ coupling scheme to reproduce experimental energy levels and calculated $P$ as function of external electric field.

The calculation of the parity-violating polarizations in the external electric field, which are associated with the electron electric dipole moment ($e$EDM) and magnetic quadrupole moment (MQM) of the $^{175}$Lu nucleus, as well as the determination of the rovibrational structure for the $^{175}$LuOH$^+$ cation, is performed. Beyond the bending of the molecule, the slight effect of the stretching of the distance between Lu and OH is taken into account. This study is required for the preparation of the experiment and for the extraction of the $e$EDM and MQM values of $^{175}$Lu from future measurements., Comment: arXiv admin note: text overlap with arXiv:2211.02112

Hyperfine structure of the ground rotational level of the metastable $^3\Delta_1$ electronic state of $^{180}$HfF$^+$ ion is calculated at presence of variable external electric and magnetic fields. Calculations are required for analysis of systematic effects in experiment for electron electric dipole moment ($e$EDM) search. Different perturbations in molecular spectra important for $e$EDM spectroscopy are taken into account., Comment: arXiv admin note: text overlap with arXiv:2302.02856

Conical intersections are crossing points or lines between two or more adiabatic electronic potential energy surfaces in the multi-dimensional coordinate space of colliding atoms and molecules. Conical intersections and corresponding non-adiabatic coupling can greatly affect molecular dynamics and chemical properties. In this paper, we predict significant or measurable non-adiabatic effects in an ultracold atom-ion charge-exchange reaction in the presence of laser-induced conical intersections (LICIs). We investigate the fundamental physics of these LICIs on molecular reactivity under unique conditions: those of relatively low laser intensity of $10^8$ W/cm$^2$ and ultracold temperatures below 1 mK. We predict irregular interference effects in the charge-exchange rate coefficients between K and Ca$^+$ as functions of laser frequency. These irregularities occur in our system due to the presence of two LICIs. To further elucidate the role of the LICIs on the reaction dynamics, we compare these rate coefficients with those computed for a system where the CIs have been ``removed''. In the laser frequency window, where conical interactions are present, the difference in rate coefficients can be as large as $10^{-9}$ cm$^3$/s., Comment: 7 pages, 5 figures and supplementary information

We describe the obstruction to decomposing in degrees $\leq p$ the de Rham complex of a smooth variety over a perfect field $k$ of characteristic $p$ that lifts over $W_2(k)$, and show that there exist liftable smooth projective varieties of dimension $p+1$ whose Hodge-to-de Rham spectral sequence does not degenerate at the first page. We also describe the action of the Sen operator on the de Rham complex in degrees $\leq p$ and give examples of varieties with a non-semisimple Sen operator. Our methods rely on the commutative algebra structure on de Rham and Hodge-Tate cohomology, and are inspired by the properties of Steenrod operations on cohomology of cosimplicial commutative algebras. The example of a non-degenerate Hodge-to-de Rham spectral sequence relies on a non-vanishing result on cohomology of groups of Lie type. We give applications to other situations such as describing extensions in the canonical filtration on de Rham, Hodge, and \'etale cohomology of an abelian variety equipped with a group action. We also show that the de Rham complex of a smooth variety over $k$ is formal as an $E_{\infty}$-algebra if and only if the variety lifts to $W_2(k)$ together with its Frobenius endomorphism., Comment: comments welcome!

The current constraint on the electron electric dipole moment ($e$EDM), $|d_e|<4.1\times 10^{-30}$ ${e {\cdotp} {\rm cm}}$ (90\% confidence), was recently established using the trapped $^{180}$Hf$^{19}$F$^+$ molecular ions in the $J=1$ rotational level of its $ ^3\Delta_1$ electronic state [T. S. Roussy, L. Caldwell, T. Wright, et al., arxiv:2212.11841]. The extensive experimental study of the HfF$^+$ cation provides detailed spectroscopy of the $\Omega-$doublet levels in the external rotating electric and magnetic fields. We showed that previously developed theoretical approaches can fully reproduce the latest experimental data. Their justification from the first principles is very important for the examination of both modern molecular theory and possible systematic uncertainties in the interpretation of the experimental data obtained with high accuracy.

Molecules containing short-lived, radioactive nuclei are uniquely positioned to enable a wide range of scientific discoveries in the areas of fundamental symmetries, astrophysics, nuclear structure, and chemistry. Recent advances in the ability to create, cool, and control complex molecules down to the quantum level, along with recent and upcoming advances in radioactive species production at several facilities around the world, create a compelling opportunity to coordinate and combine these efforts to bring precision measurement and control to molecules containing extreme nuclei. In this manuscript, we review the scientific case for studying radioactive molecules, discuss recent atomic, molecular, nuclear, astrophysical, and chemical advances which provide the foundation for their study, describe the facilities where these species are and will be produced, and provide an outlook for the future of this nascent field.

The LuOH$^+$ cation is a promising system to search for manifestations of time reversal and spatial parity violation effects. Such effects in LuOH$^+$ induced by the electron electric dipole moment $e$EDM and the scalar-pseudoscalar interaction of the nucleus with electrons, characterized by $k_s$ constant, in LuOH$^+$ are studied. The enhancement factors, polarization in the external electric field, hyperfine interaction, rovibrational structure are calculated. The study is required for the experiment preparation and extraction of the eEDM and ks values from experimental data.

Significant suppression of radiation in 3D structured media with small refractive index 1.4-1.6, such as of glass or polymers, is a desirable feature yet to be obtained. For periodical structures this is realised at frequencies of the complete photonic band gap (CPBG), which up to now was demonstrated to open for materials with refractive index of at least 1.9. We present here a quasiperiodic 3D structure consisting of multiple overlapping gratings with a homogeneous distribution of Bragg peaks on a sphere in reciprocal space, which allows efficient suppression of emission. Recently we have presented the theoretical model, considering interaction with the neighbouring gratings only, that estimates a finite CPBG for arbitrarily small refractive indices and thus complete emission suppression in infinite structures. However, numerical simulations demonstrate a finite leakage of power from emitter not predicted by the model. Still the simulations show -10 dB suppression in 3D structures with optimised number of gratings. Astonishingly, as we show here, this limit is almost independent of the refractive index contrast. Also, the structures with a defined number of gratings show maximal suppression at certain refractive indices, losing the suppression even at higher refractive indices. The -10 dB suppression is demonstrated for refractive index contrast as low as 1.30.

The energy shift in molecular spectra due to interaction of nuclear magnetic quadrupole moment ($M$) with electrons is equal to $\delta E_M = MW_M P_{ M}$, where $W_M$ is a constant determined by the electronic structure of the molecule and $P_{ M}$ is a dimensionless constant. We extended the method for calculation of parity nonconservation effects in triatomic molecules developed in Ref. [A. Petrov and A. Zakharova, Phys. Rev. A ${\bf 105}$, L050801 (2022)] to the case of $P_{ M}$ constant and applied it to $^{173}$YbOH in the first excited $v=1$ bending mode. Results of our calculations are required for the extraction of the $M$ value from the YbOH experiment., Comment: 5 pages, 3 figures

The ytterbium monohydroxide is a promising molecule for a new physics searches. It is well known that levels of the opposite parity, separated by the energy split, so-called $l$-doublets, define the experimental electric field strength required for the molecule polarization. In addition, in our previous paper [Phys.Rev. A 105, L050801 (2022)] we have shown that the value of $l$-doubling directly influences the sensitivity of linear triatomic molecules to the $\mathcal{P}$,$\mathcal{T}$-odd effects. In our work [The JCP 155, 164301 (2021)] we have calculated the value of $l$-doubling for the YbOH molecule with approximation of fixed O-H bond length. Accounting the importance of this property, in the present study we consider the additional degree of freedom corresponding to the ligand (OH) deformation., Comment: 5 pages, 3 figures

Static electric dipole moments of nondegenerate systems probe mass scales for physics beyond the Standard Model well beyond those reached directly at high energy colliders. Discrimination between different physics models, however, requires complementary searches in atomic-molecular-and-optical, nuclear and particle physics. In this report, we discuss the current status and prospects in the near future for a compelling suite of such experiments, along with developments needed in the encompassing theoretical framework., Comment: Contribution to Snowmass 2021; updated with community edits and endorsements

Electron electric dipole moment (eEDM) search using lasercoolable triatomics like YbOH is one of the most sensitive probes for physics beyond the Standard Model. The eEDM-induced energy shift is proportional to polarization ($P$) of the molecule. Similarly to diatomics with $\Omega-$doubling structure it was assumed that for triatomics with $l-$doubling structure, related to the vibrational angular momentum, $P$ can easily be saturated to almost 100\% value with moderate external electric field. We developed the method for calculation of properties of triatomic molecules and applied it to calculation of $P$ of $^{174}$YbOH in the first excited $v=1$ bending mode. Calculations showed that the most of the levels reach less than 50\% efficiency. We showed that this fact is related to the Hund's case $b$ coupling scheme of YbOH. As coupling scheme (for $\Omega=1/2$ molecules) approaches $a$ (or $c$) case polarization increases up to 100\% value. Results of our calculations should be used for correct extracting of eEDM value from YbOH experiment and similar calculations are required for other molecules.

We prove that any semi-simple representation of the Galois group of a number field coming from geometry appears as a subquotient of the ring of regular functions on the pro-algebraic completion of the fundamental group of the projective line with $3$ punctures., Comment: Corrected the proof of Lemma 6.2, other minor edits. Comments welcome!

The spectrum of triatomic molecules with close rovibrational opposite parity levels is sensitive to the $\mathcal{P}$,$\mathcal{T}$-odd effects. This makes them a convenient platform for the experimental search of a new physics. Among the promising candidates one may distinguish the YbOH as a non-radioactive compound with a heavy atom. The energy gap between levels of opposite parity, $l$-doubling, is of a great interest as it determines the electric field strength required for the full polarization of the molecule. Likewise, the influence of the bending and stretching modes on the sensitivities to the $\mathcal{P}$,$\mathcal{T}$-violation requires a thorough investigation since the measurement would be performed on the excited vibrational states. This motivates us to obtain the rovibrational nuclear wavefunctions, taking into account the anharmonicity of the potential. As a result, we get the values of the $E_{\rm eff}$ and $E_s$ for the lowest excited vibrational state and determine the $l$-doubling, Comment: 8 pages, updated the finite field results, improved the averaging procedure

The electronic structure of magnetic lanthanide atoms is fascinating from a fundamental perspective. They have electrons in a submerged open 4f shell lying beneath a filled 6s shell with strong relativistic correlations leading to a large magnetic moment and large electronic orbital angular momentum. This large angular momentum leads to strong anisotropies, i. e. orientation dependencies, in their mutual interactions. The long-ranged molecular anisotropies are crucial for proposals to use ultracold lanthanide atoms in spin-based quantum computers, the realization of exotic states in correlated matter, and the simulation of orbitronics found in magnetic technologies. Short-ranged interactions and bond formation among these atomic species have thus far not been well characterized. Efficient relativistic computations are required. Here, for the first time we theoretically determine the electronic and ro-vibrational states of heavy homonuclear lanthanide Er2 and Tm2 molecules by applying state-of-the-art relativistic methods. In spite of the complexity of their internal structure, we were able to obtain reliable spin-orbit and correlation-induced splittings between the 91 Er2 and 36 Tm2 electronic potentials dissociating to two ground-state atoms. A tensor analysis allows us to expand the potentials between the atoms in terms of a sum of seven spin-spin tensor operators simplifying future research. The strengths of the tensor operators as functions of atom separation are presented and relationships among the strengths, derived from the dispersive long-range interactions, are explained. Finally, low-lying spectroscopically relevant ro-vibrational energy levels are computed with coupled-channels calculations and analyzed., Comment: 19 pages, 6 figures

The planar problem of a viscous laminar flow around elliptical cylinders under angle of attack is considered. From the solution of the laminar boundary layer equations using the Loytsyansky local similarity method, the shear stress at the ellipse boundary and the separation point is found. From the separation points velocities equality, the circulation is found. A complete solution to the problem of the velocity and pressure field outside the boundary layer is also constructed. The coefficients of lift and resistance are found depending on the angle of attack and the ellipse axes ratio. The theoretical results are compared with the available experimental data and direct numerical solutions of the Navier-Stokes equations.