Variation Of Constants Research Articles

Stabilization of constant power loads and dynamic current sharing in DC microgrid using robust control technique

DC microgrids are appealing in distribution networks due to their high efficacy, stability, and ease of incorporation with renewable energy resources. In order to maintain system reliability, load sharing is crucial, because disturbances such as the constant power load (CPL), constant voltage load (CVL), uncertainty parameters, and variations in input voltage may result in instability. The conventional droop control method has been frequently employed to regulate the DC microgrid. However, under significant disturbances, conventional droop control is not suitable for achieving both accurate current sharing and acceptable voltage regulation. To tackle these limitations, this paper introduces a robust control for sharing load current and regulating DC bus voltage in a DC microgrid feeding a CPL and CVL. The proposed approach is split into two loops. The main loop, which is based on an RST controller, is used to regulate the current load sharing between two parallel boost DC/DC converters, handle the instability issue caused by disturbances, and improve system reliability. The DC bus voltage is adjusted using the secondary loop built using the proportional-integral (PI) controller. The key benefits are precise voltage regulation, load power sharing, and good reliability. Aside from that, the RST controller has great resilience, quick dynamic response, and strong stability for significant load fluctuations. The feasibility and efficacy of the proposed approach are confirmed by time-domain simulation results, and hardware-in-the-loop (HIL) testing under various scenarios. The obtained findings show that the suggested control strategy is capable of ensuring proportionate power-sharing while dealing with DC voltage instability under CPL, CVL, uncertainty parameters, and input voltage fluctuations.

The ultralow loss Li2Mg3Ti1−xAl4x/3O6 microwave dielectric ceramics and its design of dielectric resonator antenna

The Li2Mg3Ti1−xAl4x/3O6 (0 ≤ x ≤ 0.1) ceramics are synthesized using the solid phase method, showing excellent microwave dielectric properties with εr = 14.05, Q × f = 144 500 GHz, and τf = −43 ppm/°C at x = 0.04. Rietveld refinements, based on the XRD data, reveal that the Li2Mg3Ti1−xAl4x/3O6 ceramics crystallize in the rock salt structure with Fm-3m space group. The relationship between the crystal structure and intrinsic microwave dielectric properties is studied in detail. The variation in the dielectric constant is related to ionic polarization and relative density. The quality factor (Q × f) demonstrates a strong correlation with lattice energy, relative density, and concentration of Ti3+. The variation of τf is influenced by the bond thermal expansion coefficient and bond valence. The dielectric resonant antenna, manufactured from Li2Mg3Ti0.96Al0.0533O6-0.09TiO2 ceramic with near-zero τf, shows a bandwidth of 230 MHz at 7.40 GHz and a high radiant efficiency, which indicates that high-quality factor Li2Mg3Ti0.96Al0.0533O6 ceramic has significant potential in relevant fields such as 5G and smart driving.

Nano-Magnonic Crystals by Periodic Modulation of Magnetic Parameters

Magnonic crystals are metamaterials whose magnon behavior can be controlled for specific applications. To date, most magnonic crystals have relied on nanopatterning and magnetostatic waves. Here, we analytically and numerically investigate magnonic crystals defined by modulating magnetic parameters at the nanoscale, which predominantly act on exchange-dominated, sub-100 nm magnons. We focus on two cases: the variation in the exchange constant, and the DMI constant. We found that the exchange constant modulation gives rise to modest band gaps in the forward volume wave and surface wave configurations. The modulation of the DMI constant was found to have little effect on the magnonic band structure, leading instead to a behavior expected for unpatterned thin films. We believe that our results will be interesting for future experimental investigations of nano-designed magnonic crystals and magnonic devices, where material parameters can be locally controlled, e.g., by thermal nano-lithography.

Enhanced dielectric, electrical and electro-optical properties: Towards understanding the interaction in mesophases of 8OCB liquid crystal dispersed with CdSe/ZnS quantum dots

The current advancements in developing new liquid crystalline materials for the next generation applications focus mainly on improving the physical characteristics of the liquid crystal (LC) systems. Recent progress has shown that the functionalized nanoparticles embedded in LC matrices can significantly alter the characteristics of the LC material based on the mutual interaction between the host molecules and guest particles. In this aspect, the present study reports the impact of dispersing core-shell type CdSe/ZnS quantum dots (QDs) on the dielectric, electrical and electro-optical properties of the 8OCB LC doped at various concentrations. The doped samples exhibit an ion releasing behavior and this effect becomes more evident as the doping concentration increases up to 0.2 wt% in the LC system. It is explained as a result of the growing tactoid-like ellipsoidal form acquired by QDs owing to the enhanced mutual interaction among QD ligands and rod-like LC molecules. The temperature variation of the diffusion constant, conductivity, ionic mobility and mean relaxation time of ions significantly follows each other in all the studied samples. Moreover, thermal profiles of the dielectric anisotropy, threshold voltage and splay elastic constant show a decreasing pattern with an increment in doping concentration. A dual-relaxation regime is experimentally investigated, corresponding to the contribution of nematic director and dimers, providing two kinds of rotational viscosity in the pristine and QDs dispersed LC samples. The transmittance-voltage curve reveals the presence of residual value in the dispersed samples and is related to the volatile memory effect. A slight enhancement is observed in the photoluminescence intensity for the lower doped sample and reduces further with increasing doping concentration in the pristine LC system. All these findings suggest the considerable contribution of functionalized QDs to the studied properties in terms of interaction between the LC and dopant material. This study will further elucidate the selection of optimal QDs concentration based on the required properties for their potential applications in futuristic devices based on LCs.

Global exponential convergence and synchronization for exponential numerical competitive neural networks with different time scales and fuzzy logic

For nonlocal fuzzy delayed competitive neural networks, a novel difference model is first developed in this article using the Mittag-Leffler Euler difference method. Secondly, the existence of a sole globally bounded solution and globally exponential stability to the discrete-time networks are addressed based on Banach contractive mapping principle and the constant variation formula for sequences. Besides, exponential synchronization of the discrete-time networks is investigated and a feedback controller is designed from the viewpoint of the theory of controls. It is the first time to consider nonlocal fuzzy delayed competitive neural networks by using Mittag-Leffler Euler differences. In contrast to nonlocal discrete approaches, such difference competitive neural networks could preferably figure the features of continuous networks. The difference method in this paper extends and improves the traditional difference approaches, for example, Adams-Bashforth Euler differences. Moreover, this article explores some avenue for the research of discrete-time fractional-order systems and develops a set of theories and methodologies for the future investigations.

Convergence properties of fine structure constant measurements using quasar absorption systems

ABSTRACT Searches for space–time variations of fundamental constants have entered an era of unprecedented precision. New, high-quality quasar spectra require increasingly refined analytical methods. In this paper, a continuation in a series to establish robust and unbiased methodologies, we explore how convergence criteria in non-linear least-squares optimization impact on quasar absorption system measurements of the fine structure constant α. Given previous claims for high-precision constraints, we critically examine the veracity of a so-called blinding approach, in which α is fixed at the terrestrial value during the model building process, releasing it as a free parameter only after the ‘final’ absorption system kinematic structure has been obtained. We show that this approach results in such small consecutive parameter steps during minimization that convergence is unlikely to be reached, even after as many as 1000 iterations. The fix is straightforward: α must be treated as a free parameter from the earliest possible stages of absorption system model building. The implication of the results presented here is that all previous measurements that have used initially fixed α should be reworked.

Stark broadening data for ultraviolet lines of Ni v

ABSTRACT We provide in this work Stark broadening data (widths and shifts) for 120 ultraviolet spectral lines of Ni v ion. Our calculations are performed using the semiclassical perturbation method. For energy levels and oscillator strength calculations, we use the multiconfiguration Hatree–Fock approach. Stark shifts and widths are calculated for collisions with electrons and with the positive ions: H+, He+, and He++, allowing us to take into account the important perturbers in stellar atmospheres. We compare our Stark widths with estimations obtained using the Cowley formula. Our electron impact Stark widths are also fitted with temperature using a logarithmic formula. Finally, our obtained Stark widths are used to investigate the influence of Stark broadening in the atmospheric conditions of hot DA white dwarfs. Despite the importance of ultraviolet lines of Ni v ion for modelling white dwarf atmospheres and also for investigations of variation of fundamental constants with gravitational potential, we did not find Stark broadening data previously calculated or measured for Ni v ion. The objective of this work is to give the missed data.

TSA and FEM Analysis Applied to CAD/CAM Titanium All-on-Four Prosthesis

Patient with fully edentulous maxillaries often suffer of several disease as an alteration of facial appearance, difficulties in eating, speech, and chews. Fixed and removable prosthesis can be a solution to rehabilitate this issue. The All-on-Four protocol is one of the possible treatment modalities for implant-supported prosthetics. It consists of placing four implants in an intermorainal position, two perpendicular to the occlusal plane and two tilted distally at a 45° angle. This paper aims to assess the stress distribution on an All-on-Four titanium prosthesis by means of a Thermoelastic Stress Analysis (TSA). This full-field non-contact measurement technique allows, through a thermal imaging camera, to observe how the surface temperature of an object changes under the effect of cyclic load. The principle on which thermoelastic analysis is based is the existence of a relationship between deformation, hence applied stress, and temperature change, called the thermoelastic effect. To perform the tests, the prosthesis was fixed to a resin jaw cast that has similar characteristics to the human bone, so that the same damping that would be present under normal working conditions could be accounted for. The distal artificial molar tooth was kept in contact to a narrow screw, which was attached to a Medium-Force (M-Series) Air-Cooled Shakers made by Santek. This shaker generates a sinusoidal load of 800N with a load cell at 10 Hz frequency, which can maintain the temperature variation of the prosthesis constant. A pre-load was applied before starting the tests. To see the change in temperature a Flir A6751SC thermal camera was used, and videos were acquired with a frame rate of 125 Hz and a resolution of 640x512 pixels. From the experimental TSA tests, the trend of the experimental stress concentration on the titanium specimen was detected. The outcomes of the experimental tests were compared to a 3D prosthesis model by Finite Element Analysis (FEM).

Tunable Dielectric Spectroscopy of PVDF Thin Films Crossbred with TiO2 Nanoparticles for the Storage Devices

AbstractPolyvinylidenefluoride (PVDF) is a semi‐crystalline ferroelectric polymer with a wide range of interesting properties and shows potentiality in a variety of technological applications. Flexible thin films of PVDF nanocomposites (NCs) have attracted many researchers due to their tunable electronic properties. This paper reports the synthesis, characterization, and dielectric studies of PVDF‐TiO2 NC thin films. The synthesized films are self‐supporting thin and the average thickness of the thin films is 60 µm measured using a Digital thickness gauge of resolution 0.01 mm. TiO2 nanoparticles are prepared using the combustion method. Commercially available PVDF granules are used to develop PVDF‐TiO2 NC thin films using the film casting technique. The structural study of the prepared thin films is carried out using XRD that confirms the retention of the β‐phase of PVDF. The functional group and bonding nature have been studied using FTIR Spectroscopy. The thermal stability of the NC thin films is studied using TGA. The variation of dielectric constant (DC), dielectric loss (DL), AC conductivity, and dissipation factor of the medium of pristine PVDF and PVDF‐TiO2 NC thin films are studied in the frequency range of 10 Hz to 8 MHz at ambient temperature. The dielectric constant of PVDF‐TiO2 NC thin films increases up to 8 wt% and anomaly for 10 wt% of TiO2 fillers in the PVDF matrix at a lower frequency and found to decrease with increasing frequency. The dielectric loss of NC thin films is high at a lower frequency and decreases with an increase in the frequency that is in good agreement with the Maxwell–Wagner type of interfacial polarization. At lower frequencies, the dielectric constant of PVDF‐TiO2 NC increases with the increase in filler content. AC conductivity shows a sharp increase at higher frequencies whereas the dissipation factor of the polymer NCs remains unaltered with respect to frequency by maintaining the trend. This suggests that PVDF‐TiO2 NC is potential material for energy storage devices.

Induction of estrus as a strategy to improve the economic efficiency of the sheep flock

Productivity and profitability in sheep production systems are strongly influenced by the reproductive capacity of the flock.
 Objective: To evaluate the use of reproductive biotechnologies (e.g., the induction of estrus) and its impact on the economic efficiency and the productive and reproductive performance of technified sheep production systems, during the seasonal anestrus.
 Design/Methodology/Approach: Four-hundred recently weaned (60 days postpartum) ewes of the Katahdin breed were randomly divided into two treatments: T1 = natural mating (n= 200) and T2 = induction of estrus (n=200). Estrus was induced through the application of intravaginal sponges, impregnated with 20 mg of chronolone, plus the injection of 400 IU of Equine Chorionic Gonadotropin. The aim was to evaluate the reproductive and economic efficiency of the flock.
 Results: The induction of estrus during the seasonal anestrus recorded increases (p<0.001) in prolificacy (32%), fertility (86%), and kilograms of lamb weaned per year per ewe (48%), while decreases (p <0.05) were recorded in the number of open days (25%), calving interval (11%), cost per open days (23%), and the kilograms of lamb required per ewe per year (10%).
 Study Limitations/Implications: The constant variations in the price of supplies and services caused changes in the economic indicators.
 Findings/Conclusions: The use of reproductive biotechnologies (such as estrus induction) has a positive impact on production units, improving their profitability.

An innovative near-infrared fluorescent probe with FRET effect for the continuous detection of Zn2+ and PPi with high sensitivity and selectivity, and its application in bioimaging

As the second most abundant transition metal element in the human body, zinc ions play an important role in the normal growth and development of the human body. We have successfully synthesized a near-infrared fluorescent probe with FRET effect for the detection of Zn2+. Probe DR6G has good selectivity and anti-interference ability for Zn2+. When Zn2+ is added to the probe DR6G solution, it responds completely within seconds, releasing red fluorescence with a detection limit of 2.02 × 10−8 M. As the main product of ATP hydrolysis, PPi is indispensable in various metabolic activities in cells and the human body. Due to the strong binding ability of Zn2+ and PPi, it is easy to form ZnPPi precipitation, so we added PPi to the solution to complete the Zn2+ detection, and realized the continuous detection of PPi, and the detection limit was 2.06 × 10−8 M. Since Zn2+ and PPi play an important role in vivo, it is of great practical significance to design and synthesize a fluorescent probe that can continuously detect Zn2+ and PPi. Biological experiments have shown that the probe DR6G has low cytotoxicity and can complete the detection of exogenous Zn2+ and PPi in cells and living mice in vitro. Bacterial experiments have shown that the DR6G probe also has certain research value in the field of environmental monitoring and microbiology. Due to the constant variation of the fluorescence signals of Zn2+ and PPi during detection, we designed the logic gate program. In practical applications, the probe DR6G can quantitatively detect Zn2+ in zinc-containing oral liquids and qualitatively detect PPi in toothpaste.

A Spectroscopic Investigation of the Lowest Electronic States of the I+ 2 Cation as a Candidate for Detecting the Time Variation of Fundamental Constants

The four lowest Ω substates (X2Π3/2,g, X2Π1/2,g, A2Π3/2,u and A2Π1/2,u) of the I+ 2 cation have been studied by high-precision ab initio calculations in comparison with experimental high-resolution absorption spectra. The potential energy curves were calculated using the multi-reference configuration interaction (MRCI) method and Dirac method, respectively. Rovibrational levels of these electronic states were derived by solving the radial Schrödinger rovibrational equation. Molecular constants were obtained in fitting energy levels to a spectroscopic model. Using the fit spectroscopic constants and newly calculated transition dipole moment matrix elements, line strengths of vibronic bands in the A2Π3/2,u- X2Π3/2,g system, as well as Einstein A coefficients for 45 of these bands with ν′ = 11−19 and ν′′ = 1−5, have been derived. The Einstein A coefficients were used to compute radiative lifetimes of the ν′ = 11−19 vibrational levels of the A2Π3/2,u state. Enhancement factors for detecting the variation of the fine-structure constant (α) and the proton-to-electron mass ratio(µ) using transitions between nearly degenerate rovibronic levels of these low-lying states have been calculated.

The stress state of a plate with several holes under the action of axial tensile load

The purpose of the research is to develop a numerical method for determining the stress state of plates with several holes. The research approach is based on the development of the superposition method for singular solutions. The study objective is to solve a practical problem of determining the stress concentration coefficients in a plate with two holes of the same diameter. The study uses the numerical method of elasticity theory in the form of a superposition of four special solutions, each of which lies entirely within the corresponding hole contour. The resulting contour integrals in the displacement formula are replaced by their approximate values using the M-point trapezoidal formula or the Gaussian quadrature formula. Equating to zero the expression in variations of unknown constants (the principle of minimum potential strain energy), we have obtained a system of linear algebraic equations 4MN of unknown distribution densities. After determining the constants using known formulas, the stress-strain state of the plate with holes can be calculated. The error of the developed method is no more than 0.6% compared to the known solution.

СТОХАСТИЧНА ДЕСКРИПТОРНА ГРА ПЕРЕСЛІДУВАННЯ

A differential pursuit game in a stochastic descriptor linear system is analyzed. The system dynamics is described by Ito’s stochastic differential algebraic equation. Solutions of the equation are presented by the formula of variation of constants in terms of the initial data and control unit. Constraints on the support functionals of two sets defined by the behaviors of the pursuer and evader are used to obtain the game completion conditions. The method of resolving functions is applied to construct a pursuer control bringing the dynamic vector of the system to a terminal set. The results are illustrated by an example of a stochastic descriptor system that describes transient states in a radio technical filter with random perturbations in the form of white noise. Keywords: stochastic differential algebraic equation, Wiener process, descriptor system, differential game, radio technical filter, white noise.

High quality factor double negative metamaterial for textile fabric and fabric moisture sensing applications

This study introduces an innovative high-Quality factor (Q-factor) double negative (DNG) metamaterial sensor designed for textile fabric and fabric moisture sensing applications in the dynamic realm of textile innovation. The sensor is specifically designed to detect the dielectric properties and moisture content of different textile fabrics. The high Q-factor of this metamaterial structure ensures heightened sensitivity and accuracy in fabric sensing, facilitating precise detection of even subtle changes in fabric properties. By measuring frequency shifting and analyzing S21 values, the sensor provides crucial information about the fabric’s dielectric characteristics. Sensing experiments conducted on various fabrics, including cotton, denim, corduroy, organza, and polyester unveil distinctive patterns of frequency shifting and Q-factors, establishing a nuanced link between fabric structure and sensor performance. The proposed sensor is capable of detecting fabrics with a very low dielectric constant variation of 0.05. In the experiment, the high-dielectric fabric denim (1.7) exhibited frequency shifting and Q-factor of 6970 and 834.87, respectively. Moreover, it is worth noting that the low-dielectric fabric organza (1.03) exhibits frequency shifting and Q factors of 2190 and 1367.03, respectively. Experimental results affirm the prominent efficacy of the proposed sensor in fabric and fabric moisture sensing. Its high Q-factor empowers the sensor to accurately detect and monitor fabric properties, rendering it highly suitable for critical tasks such as quality control, energy efficiency optimization, and process enhancement within the textile industry. The proposed metamaterial sensor (MMS) can significantly contribute to the development of a smart textile sensing technology and pave the way for innovative applications in the textile industry.

Reaction rate constant: a theoretical description from local temperature.

Application of various descriptors based on electron density and its associated quantities to quantify chemical reactivity within the conceptual density functional theory has recently come into spotlight. Among others and particularly relevant to our study, local temperature based on electron density as well as kinetic energy density, as a measure of the kinetic energy of an electron moving in the Kohn-Sham potential of systems, should be mentioned. In this work, we propose to use the local temperature for describing the reaction rate constant, where our main idea originates from the point that the smaller the local temperature at the reaction center, the easier the electron removal, leading to a larger rate constant. On the basis of theoretical considerations, it is proved that the rate constant variations caused by the substituent effects can well be proportional to the local temperature at the reaction center. In order to numerically validate our proposed approach, we have taken the phenol derivatives with the available experimental rate constants of their O-methylation reaction as working models. The reason for this choice is that one of the most versatile approaches for labeling biologically active compounds with the 11C nuclide for positron emission tomography (PET) is methylation by methyl iodide including 11C nuclide, [11C]MeI, where methylation of phenolic oxygen with [11C]MeI is utilized to label some important tracers for PET studies. Our results unveil that the local temperature changes at the reaction center of the aforementioned reaction are reasonably correlated with the rate constant variations. Hopefully, incorporating the proposed correlations between the local temperature and the kinetics data into a computer control algorithm not only provides a simple tool for predicting the rate constant of the O-methylation reaction for other substituted phenols, but also, as a part of the chemical artificial intelligence, the optimum [11C]MeI labeling conditions for a wide variety of phenol derivatives can be controlled.

Hydrothermal as a synthesis method for characterization of structural, morphological and magnetic properties of Co–Al ferrite nanoparticles

This work provides a set of structural, morphological, and magnetic results for the CoFe2-xAlxO4 (x = 0.00, 0.25, 0.50, 0.75, 1.00 at %) ferrite nanoparticles synthesized by the hydrothermal route. X-ray diffraction analysis (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Spectroscopy (EDAX), High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED) microscopy and Fourier-Transform Infrared Microscopy (FTIR) were used to characterize the structural and morphological features of the prepared magnetic nanoparticles. Rietveld refinement carried out by the Material Analyses Using Diffraction (MAUD) software confirmed the formation of a single-phase spinel structure with no trace of impurity phase. FESEM micrographs showed the appearance of the ferrite nanoparticles with a size distribution in agreement with the data reported by XRD. HRTEM analysis showed the formation of cubic-shaped nanoparticles with dimensions near to the data extracted from XRD. The formation of spinel structure was approved by the FTIR spectra. The magnetic measurements through VSM analysis showed that the incorporation of Al3+ cations into the cobalt ferrite lattices decreases the values of saturation magnetization from about 69 emu/g to near 26 emu/g, which was attributed to the none-magnetic nature of Al3+ cations. The values of the coercive field, on the other hand, indicate a fluctuating trend as a function of Al3+ doping. The coercivity behavior was mainly affected by cation distribution, the variation of anisotropy constant, and the size of crystallites. All the obtained data showed that the magnetic ferrite nanoparticles could be synthesized successfully through the hydrothermal method as a technique that has not been used previously to prepare Co–Al ferrite nanoparticles.

Organic-inorganic PTAA-SiGe transparent optical materials performance analysis for photo device applications

The SiGe materials has currently received a lot of interest due to its application for the advancement of optoelectronics and related sensor technologies. Its promising stability, and band gap-dependent performance for both bulk and nano-crystalline properties are vital as optical materials. To investigate the electrical performance of SiGe active materials based photo device, the spin coated organic p-materials contact is developed on sputtered SiGe on Quartz and ITO glass substrates. Both Si0.8Ge0.2 and Si0.9Ge0.1 films greater than 85 % visible band transparency are predicted that the deposited SiGe is nano-crystalline nature. It is also revealed from absorption-based band gap, AFM grain size and XRD analysis. The transmittance of SiGe thin film is increased with the microstrain of the films as a result, better opto-electrical performance is displayed. Ge composition though slightly makes variation of lattice constant and strain effect however, relatively lower transmittance films greater current density is exhibited. A higher rectifying ratio for lower transparent SiGe material deposited on ITO glass substrate is shown in the dark. Transparency and optoelectrical performance viewpoint white light illuminated PTAA/Si0.8Ge0.2 is shown better on Quartz substrate whereas the dark analysis PTAA/Si0.9Ge0.1 is realized more favorable on ITO glass substrate.

Boosting Photovoltaic Output by Dual External Manipulations on 1D Ferroelectric Nanorods Solar Cell: Electric Field and Giant Dielectric Constant Variation

Unlike common photovoltaic (PV) cells whose performance has been anchored, the merits for the cells made of ferroelectric crystals, due to the non‐centrosymmetric structure, provide possibility to further enhance the efficiency by dual external manipulations through increasing the internal electric field strength and the dielectric screening effect, based on anomalous photovoltaic (APV) arisen by the external poling and giant dielectric constant variation through temperature‐controlled ferro‐paraelectric phase transition. In this study, a synergistic effect achieving a 67% improvement in power conversion efficiency (PCE) of the n‐i‐p configuration solar cell by ferroelectric polarization and high dielectricity is observed, taking c‐axis‐aligned single‐crystalline ferroelectric SbSI nanorods as the active layer. The opposite poling effects are revealed leading to asymmetric characteristics in the n‐i‐p configuration. The enhancements of Jsc induced by inherent giant variation imply strong dielectric screening facilities to lower carrier cross section captured by charged defects, uniformly suppressing various recombination mechanisms, understood by the Langevin model. Therefore, solar cells employing n‐i‐p structured ferroelectric thin films as absorbing layers hold promising potential for achieving defect‐tolerance high performance through rational design, external polarization, and dielectric property control.

Accurate Determination of Blackbody Radiation Shifts in a Strontium Molecular Lattice Clock.

Molecular lattice clocks enable the search for new physics, such as fifth forces or temporal variations of fundamental constants, in a manner complementary to atomic clocks. Blackbody radiation (BBR) is a major contributor to the systematic error budget of conventional atomic clocks and is notoriously difficult to characterize and control. Here, we combine infrared Stark-shift spectroscopy in a molecular lattice clock and modern quantum chemistry methods to characterize the polarizabilities of the Sr_{2} molecule from dc to infrared. Using this description, we determine the static and dynamic blackbody radiation shifts for all possible vibrational clock transitions to the 10^{-16} level. This constitutes an important step toward millihertz-level molecular spectroscopy in Sr_{2} and provides a framework for evaluating BBR shifts in other homonuclear molecules.