arXiv subjects

Roman Ciuryło

Publications and source records attributed to Roman Ciuryło.

14 recordsLinked to original sources

arXiv2026

Benchmark measurements of absolute frequencies and collisional line-shape parameters in the CO-Ar system using comb-based FTS

We report absolute frequency measurements of the CO fundamental band, together with high-precision Ar-induced collisional line-shape parameters using comb-based Fourier-transform spectroscopy. High-quality spectra were obtained with a stable mid-IR optical frequency comb source and careful suppression of technical noise. By applying analysis methods that fully exploit the advantages of optical frequency comb spectroscopy, precise frequency calibration and robust multi-line fitting were achieved, resulting line-center fitting errors below 0.00001 cm$^{-1}$ for most transitions. The measured transition frequencies agree with HITRAN within 0.0001 cm$^{-1}$, supporting the reliability of the semi-empirical database. Multi-line fits using a speed-dependent Voigt profile yield collisional parameters for approximately 40 P- and R-branch lines, providing a reliable experimental benchmark for CO-Ar line-shape modeling.

physics.chem-ph↗

arXiv2026

Isotopic effect on collisional widths and shifts of Hg clock transition induced by cold Rb atoms

We study the isotopic dependence of collisional widths and shifts of the Hg clock transition $^1$S$_0$-$^3$P$_0$ perturbed by the Rb atoms in the temperature range from 1 nK to 1 K. For this purpose, we model the Born-Oppenheimer effective interaction potential by including the leading long-range van der Waals coefficients. For elastic collisions, we show the connection between the dependence of collision line shape parameters on the reduced mass of colliding partners as well as the variation of the scattering length in the excited and ground states of the Hg-Rb system in the $\upmu$K temperature range. We confront the full quantum scattering calculations with a semi-classical approximation for collisional widths and shifts. We show that the shape resonances in excited and ground scattering states lead to significant variations of collisional line shape parameters with the change of the reduced mass of colliding atoms. We also indicate the possible influence of inelastic collisions, which could lead to universal behavior and significantly affect the dependence of collisional broadening and shifting on the isotopic combination of colliding atoms.

physics.atom-ph↗

arXiv2025

Leveraging resonant frequencies of an optical cavity for spectroscopic measurement of gas temperature and concentration

We introduce a spectroscopic approach to primary gas thermometry, harnessing precise optical cavity resonance frequencies and ab initio molecular line intensity calculations. By utilizing CO (3-0) vibrational band lines and cavity mode dispersion spectroscopy, we achieve an uncertainty of 82 ppm (24 mK at 296 K) in line-intensity-ratio thermometry (LRT) - over an order of magnitude lower than any previously reported spectroscopic thermometry at gas pressures above 1.2 kPa. This method extends high-precision spectroscopic thermometry across a pressure range an order of magnitude larger than prior techniques, enabling a fully optical, non-contact, and molecule-selective primary amount-of-substance measurement. We further demonstrate sub-permille uncertainty in gas concentration measurements across pressures from 50 Pa to 20 kPa, significantly enhancing the precision and versatility of spectroscopic gas metrology.

physics.optics↗

arXiv2024

Heterodyne dispersive cavity ring-down spectroscopy exploiting eigenmode frequencies for high-fidelity measurements

Measuring low light absorption with combined uncertainty < 1 permille is crucial in a wide range of applications. Popular cavity ring-down spectroscopy can provide ultra-high precision, below 0.01 permille, but its accuracy is strongly dependent on the measurement capabilities of the detection system and typically is about 10 permille. Here, we exploit the optical frequency information carried by the ring-down cavity electromagnetic field, not explored in conventional CRDS, for high-fidelity spectroscopy. Instead of measuring only the decaying light intensity, we perform heterodyne detection of ring-downs followed by Fourier analysis to provide exact frequencies of optical cavity modes and a dispersive spectrum of a gas sample from them. This approach is insensitive to inaccuracies in light intensity measurements and eliminates the problem of detector band nonlinearity, the main cause of measurement error in traditional CRDS. Using the CO and HD line intensities as examples, we demonstrate the sub-permille accuracy of our method, confirmed by the best ab initio results, and the long-term repeatability of our dispersion measurements at 10^(-4) level. Such results have not been achieved in optical spectroscopy before. The high accuracy of the presented method indicates its potential in atmospheric studies, isotope ratio metrology, thermometry, and the establishment of primary gas standards.

physics.optics↗

arXiv2024

Line-shape study of CO perturbed by N${_2}$ with mid-infrared frequency comb-based Fourier-transform spectroscopy

We developed a mid-infrared optical frequency comb-based Fourier-transform spectrometer and performed a line-shape study of the fundamental vibrational band of CO perturbed by N${_2}$, which is crucial for atmospheric science and astronomical observations. The comb-based FTS enabled us to measure the whole vibrational band with high resolution and precision at several pressures between 10 and 400 Torr. Observed absorption profiles were fitted with the speed-dependent Voigt profile. Collisional broadening, speed-dependent collisional width and shift coefficients are derived. The reliability of our results is established from considerations of systematic errors and comparison with previous studies.

physics.chem-ph↗

arXiv2024

CIRCUS: an autonomous control system for antimatter, atomic and quantum physics experiments

A powerful and robust control system is a crucial, often neglected, pillar of any modern, complex physics experiment that requires the management of a multitude of different devices and their precise time synchronisation. The AEgIS collaboration presents CIRCUS, a novel, autonomous control system optimised for time-critical experiments such as those at CERN's Antiproton Decelerator and, more broadly, in atomic and quantum physics research. Its setup is based on Sinara/ARTIQ and TALOS, integrating the ALPACA analysis pipeline, the last two developed entirely in AEgIS. It is suitable for strict synchronicity requirements and repeatable, automated operation of experiments, culminating in autonomous parameter optimisation via feedback from real-time data analysis. CIRCUS has been successfully deployed and tested in AEgIS; being experiment-agnostic and released open-source, other experiments can leverage its capabilities.

quant-ph↗

arXiv2023

Engineering the sensitivity of macroscopic physical systems to variations in the fine-structure constant

Experiments aimed at searching for variations in the fine-structure constant $α$ are based on spectroscopy of transitions in microscopic bound systems, such as atoms and ions, or resonances in optical cavities. The sensitivities of these systems to variations in $α$ are typically on the order of unity and are fixed for a given system. For heavy atoms, highly charged ions and nuclear transitions, the sensitivity can be increased by benefiting from the relativistic effects and favorable arrangement of quantum states. This article proposes a new method for controlling the sensitivity factor of macroscopic physical systems. Specific concepts of optical cavities with tunable sensitivity to $α$ are described. These systems show qualitatively different properties from those of previous studies of the sensitivity of macroscopic systems to variations in $α$, in which the sensitivity was found to be fixed and fundamentally limited to an order of unity. Although possible experimental constraints attainable with the specific optical cavity arrangements proposed in this article do not yet exceed the present best constraints on $α$ variations, this work paves the way for developing new approaches to searching for variations in the fundamental constants of physics.

physics.atom-ph↗

arXiv2019

Guidelines for developing optical clocks with $10^{-18}$ fractional frequency uncertainty

There has been tremendous progress in the performance of optical frequency standards since the first proposals to carry out precision spectroscopy on trapped, single ions in the 1970s. The estimated fractional frequency uncertainty of today's leading optical standards is currently in the $10^{-18}$ range, approximately two orders of magnitude better than that of the best caesium primary frequency standards. This exceptional accuracy and stability is resulting in a growing number of research groups developing optical clocks. While good review papers covering the topic already exist, more practical guidelines are needed as a complement. The purpose of this document is therefore to provide technical guidance for researchers starting in the field of optical clocks. The target audience includes national metrology institutes (NMIs) wanting to set up optical clocks (or subsystems thereof) and PhD students and postdocs entering the field. Another potential audience is academic groups with experience in atomic physics and atom or ion trapping, but with less experience of time and frequency metrology and optical clock requirements. These guidelines have arisen from the scope of the EMPIR project "Optical clocks with $1 \times 10^{-18}$ uncertainty" (OC18). Therefore, the examples are from European laboratories even though similar work is carried out all over the world. The goal of OC18 was to push the development of optical clocks by improving each of the necessary subsystems: ultrastable lasers, neutral-atom and single-ion traps, and interrogation techniques. This document shares the knowledge acquired by the OC18 project consortium and gives practical guidance on each of these aspects.

physics.atom-ph↗

arXiv2018

Weakly bound molecules as sensors of new gravitylike forces

Several extensions to the Standard Model of particle physics, including light dark matter candidates and unification theories, predict deviations from Newton's law of gravitation. For macroscopic distances, the inverse-square law of gravitation is well confirmed by astrophysical observations and laboratory experiments. At micrometer and shorter length scales, however, even the state-of-the-art constraints on deviations from gravitational interaction, whether provided by neutron scattering or precise measurements of forces between macroscopic bodies, are currently many orders of magnitude larger than gravity itself. Here we show that precision spectroscopy of weakly bound molecules can be used to constrain non-Newtonian interactions between atoms. A proof-of-principle demonstration using recent data from photoassociation spectroscopy of weakly bound Yb$_2$ molecules yields constraints on these new interactions that are already close to state-of-the-art neutron scattering experiments. At the same time, with the development of the recently proposed optical molecular clocks, the neutron scattering constraints could be surpassed by at least two orders of magnitude.

physics.atom-ph↗

arXiv2017

Optical Feshbach resonances and ground state molecule production in the RbHg system

We present the prospects for photoassociation, optical control of interspecies scattering lengths and finally, the production of ultracold absolute ground state molecules in the Rb+Hg system. We use the "gold standard" ab initio methods for the calculations of ground (CCSD(T)) and excited state (EOM-CCSD) potential curves. The RbHg system, thanks to the wide range of stable Hg bosonic isotopes, offers possibilities for mass-tuning of ground state interactions. The optical lengths describing the strengths of optical Feshbach resonances near the Rb transitions are favorable even at large laser detunings. Ground state RbHg molecules can be produced with efficiencies ranging from about 20% for deeply bound to at least 50% for weakly bound states close to the dissociation limit. Finally, electronic transitions with favorable Franck-Condon factors can be found for the purposes of a STIRAP transfer of the weakly bound RbHg molecules to the absolute ground state using commercially available lasers.

cond-mat.quant-gas↗

arXiv2014

Mass scaling and non-adiabatic effects in photoassociation spectroscopy of ultracold strontium atoms

We report photoassociation spectroscopy of ultracold $^{86}$Sr atoms near the intercombination line and provide theoretical models to describe the obtained bound state energies. We show that using only the molecular states correlating with the $^1S_0$$+$$^3P_1$ asymptote is insufficient to provide a mass scaled theoretical model that would reproduce the bound state energies for all isotopes investigated to date: $^{84}$Sr, $^{86}$Sr and $^{88}$Sr. We attribute that to the recently discovered avoided crossing between the $^1S_0$$+$$^3P_1$ $0_u^+$ ($^3Π_u$) and $^1S_0$$+$$^1D_2$ $0_u^+$ ($^1Σ^+_u$) potential curves at short range and we build a mass scaled interaction model that quantitatively reproduces the available $0_u^+$ and $1_u$ bound state energies for the three stable bosonic isotopes. We also provide isotope-specific two-channel models that incorporate the rotational (Coriolis) mixing between the $0_u^+$ and $1_u$ curves which, while not mass scaled, are capable of quantitatively describing the vibrational splittings observed in experiment. We find that the use of state-of-the-art ab initio potential curves significantly improves the quantitative description of the Coriolis mixing between the two -8 GHz bound states in $^{88}$Sr over the previously used model potentials. We show that one of the recently reported energy levels in $^{84}$Sr does not follow the long range bound state series and theorize on the possible causes. Finally, we give the Coriolis mixing angles and linear Zeeman coefficients for all of the photoassociation lines. The long range van der Waals coefficients $C_6(0_u^+)=3868(50)$~a.u. and $C_6(1_u)=4085(50)$~a.u. are reported.

physics.atom-ph↗

arXiv2013

Scattering lengths in isotopologues of the RbYb system

We model the binding energies of rovibrational levels of the RbYb molecule using experimental data from two-color photoassociation spectroscopy in mixtures of ultracold $^{87}$Rb with various Yb isotopes. The model uses a theoretical potential based on state-of-the-art \emph{ab initio} potentials, further improved by least-squares fitting to the experimental data. We have fixed the number of bound states supported by the potential curve, so that the model is mass scaled, that is, it accurately describes the bound state energies for all measured isotopic combinations. Such a model enables an accurate prediction of the s-wave scattering lengths of all isotopic combinations of the RbYb system. The reduced mass range is broad enough to cover the full scattering lengths range from $-\infty$ to $+\infty$. For example, the $^{87}$Rb$^{174}$Yb system is characterized by a large positive scattering length of $+880(120)$~a.u., while $^{87}$Rb$^{173}$Yb has $a=-626(88)$~a.u.. On the other hand $^{87}$Rb$^{170}$Yb has a very small scattering length of $-14.5(1.8)$~a.u. confirmed by the pair's extremely low thermalization rate. For isotopic combinations including $^{85}$Rb the variation of the interspecies scattering lengths is much smoother ranging from $+39.0(1.6)$ a.u. for $^{85}$Rb$^{176}$Yb to $+230(10)$ a.u. in the case of $^{85}$Rb$^{168}$Yb. Hyperfine corrections to these scattering lengths are also given. We further complement the fitted potential with interaction parameters calculated from alternative methods. The recommended value of the van der Waals coefficient is $C_6$=2837(13)~a.u. and is in agreement and more precise than the current state-of-the-art theoretical predictions (S. G. Porsev, M. S. Safronova, A. Derevianko, and C.W. Clark, arXiv:1307.2654 (2013)).

physics.atom-ph↗

arXiv2012

Controlled Production of Sub-Radiant States of a Diatomic Molecule in an Optical Lattice

We report successful production of sub-radiant states of a two-atom system in a three-dimensional optical lattice starting from doubly occupied sites in a Mott insulator phase of a quantum gas of atomic ytterbium. We can selectively produce either sub-radiant 1g state or super-radiant 0u state by choosing the excitation laser frequency. The inherent weak excitation rate for the sub-radiant 1g state is overcome by the increased atomic density due to the tight-confinement in a three-dimensional optical lattice. Our experimental measurements of binding energies, linewidth, and Zeeman shift confirm observation of sub-radiant levels of the 1g state of the Yb_2 molecule.

physics.atom-ph↗

arXiv2009

Buffer gas induced collision shift for the $^{88}$Sr $\bf{^1S_0-^3P_1}$ clock transition

Precision saturation spectroscopy of the $^{88}{\rm Sr} ^1S_0-^3P_1$ is performed in a vapor cell filled with various rare gas including He, Ne, Ar, and Xe. By continuously calibrating the absolute frequency of the probe laser, buffer gas induced collision shifts of $\sim $kHz are detected with gas pressure of 1-20 mTorr. Helium gave the largest fractional shift of $1.6 \times 10^{-9} {\rm Torr}^{-1}$. Comparing with a simple impact calculation and a Doppler-limited experiment of Holtgrave and Wolf [Phys. Rev. A {\bf 72}, 012711 (2005)], our results show larger broadening and smaller shifting coefficient, indicating effective atomic loss due to velocity changing collisions. The applicability of the result to the $^1S_0-^3P_0$ optical lattice clock transition is also discussed.

physics.atom-ph↗