Lithium Problem Research Articles

Back-decay of the muonic molecular ion (αμt)012+ resonantly formed in (tμ)1s+4HeH+ collision

Abstract Resonant formation of the muonic molecular ion ( α μ t ) 01 2 + in the collision of the muonic tritium atom with the helium hydride ion, ( t μ ) 1 s + 4 HeH + → [ ( α μ t ) 01 2 + , p , e e ] + , is proposed. The ( α μ t ) 01 2 + ion is formed in the rotational-vibrational state (0,1) as one of the two nuclei of the final complex. Back-decay process [ ( α μ t ) 01 2 + , p , e e ] K n + → ( t μ ) 1 s + 4 HeH K ′ n ′ + , where K and n ( K ′ and n ′ ) is the rotational and vibrational quantum number, respectively, is considered in detail and the corresponding decay widths for all possible rotational-vibrational ( K , n ) → ( K ′ , n ′ ) transitions are calculated. Numerous inelastic decay channels of ( α μ t ) 01 2 + are also presented and discussed. The possible fast resonant formation of the ( α μ t ) 01 2 + ion may provide an interesting tool for experimental studies of t ( α , γ ) 7 Li nuclear fusion, which is one of the most important reactions in Big-Bang nucleosynthesis models. Studying this reaction may prove important for solving the lithium problem.

Solving the Residual Lithium Problem by Substoichiometric Synthesis of Layered Ni-Rich Oxide Cathodes

Solving the Residual Lithium Problem by Substoichiometric Synthesis of Layered Ni-Rich Oxide Cathodes

A coherent view of Li depletion and angular momentum transport to explain the Li plateau – from Population II to Population I stars

Context. The discrepancy between the predictions of Big Bang nucleosynthesis and the lithium abundance observed in the oldest stars of our Galaxy, known as the cosmological lithium problem, has long been regarded as a challenge to the fields of both cosmology and astrophysics. Aims. In light of recent theoretical advances concerning the transport of chemicals and angular momentum in Population I low-mass stars, we re-examine the stellar depletion hypothesis to explain the lithium plateau, which spans a wide range of metallicities over a specific range of stellar effective temperature. Methods. We computed stellar evolution models with the code STAREVOL, including the same input physics that enable self-consistent reproduction of the Li depletion in the Sun and stars in open clusters, while accounting for internal rotation consistent with asteroseismic constraints. In addition to atomic diffusion and parametric turbulence, which were considered in previous studies of Li depletion along the plateau, our models include rotation-induced hydrodynamical processes and additional parametric viscosity for the transport of angular momentum as well as penetrative convection with a rotational dependence, and magnetic braking. Results. As in the case of Pop I stars, the mixing obtained with the current prescriptions for vertical and horizontal shear turbulence induced by rotation is insufficient to reproduce the Li constraints, and parametric turbulence is required. Even if the nature of the turbulence has yet to be identified, we show that the compactness of Pop II low-mass dwarf stars shall naturally lead to similar Li depletion over a large domain in the [Fe/H]–Teff plane, resulting in a plateau with little dispersion. We calibrated the efficiency of the turbulence to fit the abundance of Li in Pop II stars selected from the GALAH DR3 spectroscopic survey and from an homogeneous reanalysis of abundances from the literature. This calibration also enables the reproduction of lithium and magnesium trends in post-turnoff stars of the globular cluster NGC 6752. The same stellar structure considerations consistently explain the observed change of Li depletion and the dispersion regime for [Fe/H] above −1.5 dex, that is, at the transition in metallicity between Pop II to Pop I stars. Conclusions. Our results provide new constraints to the physical processes that transport chemicals and angular momentum in stellar interiors. They offer a comprehensive way to reproduce the observed Li patterns in low-mass dwarf stars across the entire Galactic metallicity range covered by spectroscopic surveys, including the most Fe-poor regime, as supported by the Li value in the non-CEMP star that lies on the plateau at [Fe/H] below −5.8 dex. Our careful analysis of the other very metal-poor stars with lower Li abundances supports the environmental origin of the so-called meltdown regime. Finally, the expected plateau-to-scatter transition pattern further supports the stellar solution to the cosmological problem.

Slow 7Be and the primordial 7Li abundance

The cross sections of neutron-induced nuclear reactions are commonly large at low energies. Given this feature, the 7Be(n, p)7Li process with slow 7Be is studied in connection with the cosmological lithium problem. An idea is tested whether slow (non-Maxwellian) 7Be born in the radiative capture 3He(α, γ)7Be reaction can boost the 7Be(n, p)7Li(p, α)α mechanism of 7Li burn-up in the early universe, reducing the amount of primordial 7Li. The rate of this sequential process is examined and its effect on the 7Li abundance is clarified. In the absence of 7Be thermalization in the primordial plasma, the above mechanism can decrease 7Li/H by several percent, leaving unchanged the abundances of D and 4He which are consistent with observations. However, taking into account the 7Be thermalization due to scattering off electrons, positrons, nuclei, and photons radically suppresses the effect. It is found that the typical thermalization time of 7Be is less than 10−5 s, while the fraction of non-Maxwellian particles in the 7Be component is at most 2 × 10−7. Under this condition, the corresponding impact on 7Li/H is estimated to be no more than 10−5%.

Big Bang Nucleosynthesis with f(R) Gravity Scalarons and Astrophysical Consequences

f(R) gravity is one of the serious alternatives of general relativity with a large range of astronomical consequences. In this work, we study Big Bang nucleosynthesis (BBN) in f(R) gravity theory. We consider a modification to gravity due to the existence of primordial black holes (PBHs) in the radiation era that introduce additional degrees of freedom known as scalarons. We calculate the light element abundances by using the BBN code PArthENoPE. It is found that for a range of scalaron mass (2.2 − 3.5) × 104 eV, the abundance of lithium is lowered by 3−4 times the value predicted by general relativistic BBN, which is a level desired to address the cosmological lithium problem. For the above scalaron mass range, the helium abundance is within the observed bound. However, the deuterium abundance is found to be increased by 3−6 times the observed primordial abundance. It calls for a high efficiency of stellar formation and evolution processes for the destruction of primordial deuterium, which is suggested as possible in scalaron gravity. A novel relation between scalaron mass and black hole mass has been used to show that the above scalaron mass range corresponds to PBHs of subplanetary mass (∼1019 g) serving as one of the potential candidates of nonbaryonic dark matter. We infer Big Bang equivalence of power-law f(R) gravity with PBHs that are detectable with upcoming gravitational wave detectors.

Photon to axion conversion during Big Bang Nucleosynthesis

We investigate how the resonant conversion at a temperature T̅ = 25–65 keV of a fraction of the CMB photons into an axion-like majoron affects BBN. The scenario, that assumes the presence of a primordial magnetic field and the subsequent decay of the majorons into neutrinos at T ≈ 1 eV, has been proposed to solve the H 0 tension. We find two main effects. First, since we lose photons to majorons at T̅, the baryon to photon ratio is smaller at the beginning of BBN (T > T̅) than during decoupling and structure formation (T ≪ T̅). This relaxes the 2σ mismatch between the observed deuterium abundance and the one predicted by the standard ΛCDM model. Second, since the conversion implies a sudden drop in the temperature of the CMB during the final phase of BBN, it interrupts the synthesis of lithium and beryllium and reduces their final abundance, possibly alleviating the lithium problem.

The Lithium Boom: Lithium Sources and Prospects for the Russian Lithium Industry

The explosive development of renewable energy in recent years is reshaping the geopolitical picture of the world. Solar panels and wind turbines have become the symbol of the new energy transition, while lithium-ion batteries have become its basis and the driver of development. It was lithium-ion batteries that made it possible to overcome the main problem of renewable energy – inconstancy and uncontrollability. The article highlights the lithium problem, the reasons for the volatility of lithium prices, the main sources of lithium and the difficulties of its production. In addition, the prospects of development of lithium industry in Russia and current domestic developments in lithium mining technology are considered.

THE LITHIUM BOOM: LITHIUM SOURCES AND PROSPECTS FOR THE RUSSIAN LITHIUM INDUSTRY

The explosive development of renewable energy in recent years is reshaping the geopolitical picture of the world. Solar panels and wind turbines have become the symbol of the new energy transition, while lithium-ion batteries have become its basis and the driver of development. It was lithium-ion batteries that made it possible to overcome the main problem of renewable energy - inconstancy and uncontrollability. The article highlights the lithium problem, the reasons for the volatility of lithium prices, the main sources of lithium and the difficulties of its production. In addition, the prospects of development of lithium industry in Russia and current domestic developments in lithium mining technology are considered

Clinicians’ preferences and attitudes towards the use of lithium in the maintenance treatment of bipolar disorders around the world: a survey from the ISBD Lithium task force

BackgroundLithium has long been considered the gold-standard pharmacological treatment for the maintenance treatment of bipolar disorders (BD) which is supported by a wide body of evidence. Prior research has shown a steady decline in lithium prescriptions during the last two decades. We aim to identify potential factors explaining this decline across the world with an anonymous worldwide survey developed by the International Society for Bipolar Disorders (ISBD) Task Force “Role of Lithium in Bipolar Disorders” and distributed by diverse academic and professional international channels.ResultsA total of 886 responses were received of which 606 completed the entire questionnaire while 206 completed it partially. Respondents were from 43 different countries comprising all continents. Lithium was the most preferred treatment option for the maintenance of BD patients (59%). The most relevant clinical circumstances in which lithium was the preferred option were in patients with BD I (53%), a family history of response (18%), and a prior response during acute treatment (17%). In contrast, Lithium was not the preferred option in case of patients´ negative beliefs and/or attitudes towards lithium (13%), acute side-effects or tolerability problems (10%) and intoxication risk (8%). Clinicians were less likely to prefer lithium as a first option in BD maintenance phase when practising in developing economy countries [X2 (1, N = 430) = 9465, p = 0.002) ] and private sectors [X2 (1, N = 434) = 8191, p = 0.004)].ConclusionsClinicians’ preferences and attitudes towards the use of lithium in the maintenance treatment of bipolar disorders appear to be affected by both the patients’ beliefs and the professional contexts where clinicians provide their services. More research involving patients is needed for identifying their attitudes toward lithium and factors affecting its use, particularly in developing economies.

Differential voltage analysis for battery manufacturing process control

Voltage-based battery metrics are ubiquitous and essential in battery manufacturing diagnostics. They enable electrochemical “fingerprinting” of batteries at the end of the manufacturing line and are naturally scalable, since voltage data is already collected as part of the formation process which is the last step in battery manufacturing. Yet, despite their prevalence, interpretations of voltage-based metrics are often ambiguous and require expert judgment. In this work, we present a method for collecting and analyzing full cell near-equilibrium voltage curves for end-of-line manufacturing process control. The method builds on existing literature on differential voltage analysis (DVA or dV/dQ) by expanding the method formalism through the lens of reproducibility, interpretability, and automation. Our model revisions introduce several new derived metrics relevant to manufacturing process control, including lithium consumed during formation and the practical negative-to-positive ratio, which complement standard metrics such as positive and negative electrode capacities. To facilitate method reproducibility, we reformulate the model to account for the “inaccessible lithium problem” which quantifies the numerical differences between modeled versus true values for electrode capacities and stoichiometries. We finally outline key data collection considerations, including C-rate and charging direction for both full cell and half cell datasets, which may impact method reproducibility. This work highlights the opportunities for leveraging voltage-based electrochemical metrics for online battery manufacturing process control.

Determination of the 3He(α, γ)7Be and 6Li(p, γ)7Be astrophysical factors down to zero energy using the asymptotic normalization coefficients

The p - p-chain reaction 3He(α, γ)7Be can sensitively influence the prediction of the 7Be and 8B neutrino fluxes. Despite its importance, the knowledge of its reaction cross section at energies of the core of the Sun (15 keV 30 keV) is limited and the accuracy far from the desired 3% level. In the present paper the indirect measurement of the external capture contribution using the asymptotic normalization coefficient (ANC) technique is reported. The angular distributions of deuterons emitted in the 6Li(3He,d)7Be α-transfer reactions were measured and the ANCs extracted from the scaling of distorted-wave Born approximation (DWBA) and coupled-channel (CC) calculations. Then, the astrophysical S-factor for the 3He(α, γ)7Be reaction was calculated assuming E1 direct capture and the zero energy value turned out to be 0.534 0.025 keVb. Both our experimental and theoretical approaches were benchmarked through the analysis of the 6Li(p,γ)7Be astrophysical factor, with interesting astrophysical applications to the understanding of the primordial lithium problem. In particular, the present work disfavors the occurrence of a claimed 200 keV resonance in the astrophysical factor.

Big Bang nucleosynthesis as a probe of new physics

The Big Bang Nucleosynthesis (BBN) model is a cornerstone for the understanding of the evolution of the early universe, making seminal predictions that are in outstanding agreement with the present observation of light element abundances in the universe. Perhaps, the only remaining issue to be solved by theory is the so-called “lithium abundance problem". Dedicated experimental efforts to measure the relevant nuclear cross sections used as input of the model have lead to an increased level of accuracy in the prediction of the light element primordial abundances. The rise of indirect experimental techniques during the preceding few decades has permitted the access of reaction information beyond the limitations of direct measurements. New theoreticaldevelopments have also opened a fertile ground for tests of physics beyond the standard model of atomic,nuclear, statistics, and particle physics. We review the latest contributions of our group for possible solutions of the lithium problem.

Implications of the non-observation of 6Li in halo stars for the primordial 7Li problem

The primordial Lithium Problem is intimately connected to the assumption that the 7Li abundance observed in metal-poor halo stars is unchanged from its primordial value, which lies significantly below the predictions of standard big-bang nucleosynthesis. Two key lines of evidence have argued that these stars have not significantly depleted their initial (mostly primordial) 7Li: i) the lack of dispersion in Li abundance measurements at low metallicity (and high surface temperature); and ii) the detection of the more fragile 6Li isotope in at least two halo stars. The purported 6Li detections were in good agreement with predictions from cosmic-ray nucleosynthesis which is responsible for the origin of 6Li. This concordance left little room for 6Li depletion, and the apparent 6Li survival implied that 7Li largely evaded destruction, because stellar interiors destroy 6Li more vigorously then than 7Li. Recent (re)-observations of halo stars challenge the evidence against 7Li depletion: i) lithium elemental abundances now show significant dispersion, and ii) sensitive 6Li searches now reveal only upper limits to the 6Li/7Li ratio. We discuss the consequences of these 6Li non-detections on the primordial 7Li Problem, Galactic cosmic-ray nucleosynthesis, and the question of differential depletion of Li in stars. The tight new 6Li upper limits generally fall far below the predictions of cosmic-ray nucleosynthesis, implying that substantial 6Li depletion has occurred — by factors up to 50. We show that in stars with 6Li limits and thus lower bounds on 6Li depletion, an equal amount of 7Li depletion is more than sufficient to resolve the primordial 7Li Problem. This picture is consistent with well-studied stellar models in which 7Li is less depleted than 6Li, and strengthen the case that the Lithium Problem has an astrophysical solution. We conclude by suggesting future observations that could test these ideas.

BBN constraints on f(Q,T) gravity

[Formula: see text] gravity is a novel extension of the symmetric teleparallel gravity where the Lagrangian [Formula: see text] is represented through an arbitrary function of the nonmetricity [Formula: see text] and the trace of the energy–momentum tensor [Formula: see text].23 In this work, we have constrained a widely used [Formula: see text] gravity model of the form [Formula: see text] from the primordial abundances of the light elements to understand its viability in cosmology. We report that the [Formula: see text] gravity model can elegantly explain the observed abundances of Helium and Deuterium while the Lithium problem persists. From the constraint on the expansion factor in the range [Formula: see text], we report strict constraints on the parameters [Formula: see text] and [Formula: see text] in the range [Formula: see text] and [Formula: see text], respectively.

Non-detection of 6Li in Spite plateau stars with ESPRESSO

ABSTRACT The detection of 6Li in Spite plateau stars contradicts the standard big bang nucleosynthesis prediction, known as the second cosmological lithium problem. We measure the isotopic ratio 6Li/7Li in three Spite plateau stars: HD 84937, HD 140283, and LP 815−43. We use 3D non-local thermodynamic equilibrium radiative transfer and for the first time apply this to high-resolution, high signal-to-noise ratio data from the ultra-stable ESPRESSO/Very Large Telescope spectrograph. These are among the best spectra ever taken of any metal-poor stars. As the measurement of 6Li/7Li is degenerate with other physical stellar parameters, we employ Markov chain Monte Carlo methods to find the probability distributions of measured parameters. As a test of systematics, we also use three different fitting methods. We do not detect 6Li in any of the three stars, and find consistent results between our different methods. We estimate 2σ upper limits to 6Li/7Li of 0.7, 0.6, and 1.7 per cent, respectively, for HD 84937, HD 140283, and LP 815−43. Our results indicate that there is no second cosmological lithium problem, as there is no evidence of 6Li in Spite plateau stars.

New Thermonuclear Rate of 7Li(d,n)24He Relevant to the Cosmological Lithium Problem

Abstract Accurate 7Li(d,n)24He thermonuclear reaction rates are crucial for precise prediction of the primordial abundances of lithium and beryllium and to probe the mysteries beyond fundamental physics and the standard cosmological model. However, uncertainties still exist in current reaction rates of 7Li(d,n)24He widely used in big bang nucleosynthesis (BBN) simulations. In this work, we reevaluate the 7Li(d,n)24He reaction rate using the latest data on the three near-threshold 9Be excited states from experimental measurements. We present for the first time uncertainties that are directly constrained by experiments. Additionally, we take into account for the first time the contribution from the subthreshold resonance at 16.671 MeV of 9Be. We obtain a 7Li(d,n)24He rate that is overall smaller than the previous estimation by about a factor of 60 at the typical temperature of the onset of primordial nucleosynthesis. We implemented our new rate in BBN calculations, and we show that the new rates have a very limited impact on the final light element abundances in uniform density models. Typical abundance variations are in the order of 0.002%. For nonuniform density BBN models, the predicted 7Li production can be increased by 10% and the primordial production of light nuclides with mass number A > 7 can be increased by about 40%. Our results confirm that the cosmological lithium problem remains a long-standing unresolved puzzle from the standpoint of nuclear physics.

Primordial nucleosynthesis with varying fundamental constants

The success of primordial nucleosynthesis has been limited by the long-standing lithium problem. We use a self-consistent perturbative analysis of the effects of the relevant theoretical parameters on primordial nucleosynthesis, including variations of nature’s fundamental constants, to explore the problem and its possible solutions in the context of the latest observations and theoretical modeling. We quantify the amount of depletion needed to solve the lithium problem, and show that transport processes of chemical elements in stars are able to account for it. Specifically, the combination of atomic diffusion, rotation, and penetrative convection allows us to reproduce the lithium surface abundances of Population II stars, starting from the primordial lithium abundance. We also show that even with this depletion factor, a preference for a value of the fine-structure constant at this epoch remains that is larger than the value currently obtained in the laboratory by a few parts per million of relative variation at a statistical significance level of two to three standard deviations. This preference is driven by the recently reported discrepancy between the best-fit values for the baryon-to-photon ratio (or equivalently, the Deuterium abundance) inferred from cosmic microwave background and primordial nucleosynthesis analyses, and is largely insensitive to the Helium-4 abundance. We thus conclude that the lithium problem most likely has an astrophysical solution, while the Deuterium discrepancy provides a possible indication of new physics.

The GALAH survey: accreted stars also inhabit the Spite plateau

ABSTRACT The European Space Agency (ESA) Gaia mission has enabled the remarkable discovery that a large fraction of the stars near the solar neighbourhood are debris from a single in-falling system, the so-called Gaia-Sausage-Enceladus (GSE). This discovery provides astronomers for the first time with a large cohort of easily observable, unevolved stars that formed in a single extragalactic environment. Here we use these stars to investigate the ‘Spite plateau’ – the near-constant lithium abundance observed in unevolved metal-poor stars across a wide range of metallicities (−3 < [Fe/H] < −1). Our aim is to test whether individual galaxies could have different Spite plateaus – e.g. the interstellar medium could be more depleted in lithium in a lower galactic mass system due to it having a smaller reservoir of gas. We identified 93 GSE dwarf stars observed and analysed by the GALactic Archaeology with HERMES (GALAH) survey as part of its Data Release 3 (DR3). Orbital actions were used to select samples of GSE stars, and comparison samples of halo and disc stars. We find that the GSE stars show the same lithium abundance as other likely accreted stars and in situ Milky Way stars. Formation environment leaves no imprint on lithium abundances. This result fits within the growing consensus that the Spite plateau, and more generally the ‘cosmological lithium problem’ – the observed discrepancy between the amount of lithium in warm, metal-poor dwarf stars in our Galaxy, and the amount of lithium predicted to have been produced by big bang nucleosynthesis – is the result of lithium depletion processes within stars.

Constraining the Primordial Lithium Abundance: New Cross Section Measurement of the 7Be + n Reactions Updates the Total 7Be Destruction Rate

Abstract The cosmological lithium problem (CLP) stems from the outstanding discrepancy between theoretical predictions and astronomical observations of primordial lithium abundances. For the radiogenic production of 7Li, 7Be plays a pivotal role in the Big Bang nucleosynthesis (BBN). Nevertheless, the data for neutron-induced 7Be destruction processes were still sparse, and especially lacked information on the contributions of transitions to the 7Li excited states. In this work, we have determined the 7Be ( n , p 0 ) 7 Li, 7Be ( n , p 1 ) 7 Li*, and 7Be ( n , α ) 4 He reaction cross sections by means of the Trojan Horse method. The present and the previous data were analyzed together by a multichannel R-matrix fit, providing an improved uncertainty evaluation of the ( n , p 0 ) channel and the first-ever quantification of the ( n , p 1 ) contribution in the BBN-relevant energy range. We implemented the revised total reaction rate summing both the ( n , p 0 ) and ( n , p 1 ) contributions in a state-of-the-art BBN code PRIMAT. As a consequence, the present nuclear-physics data offers a reduction of the predicted 7Li abundance by about one-tenth, which would impose a stricter constraint on BBN and head us in the correct direction to the CLP solution.

Big Bang nucleosynthesis in a weakly non-ideal plasma

We propose a correction of the standard Big Bang nucleosynthesis (BBN) scenario to resolve the primordial lithium problem by considering a possibility that the primordial plasma can deviate from the ideal state. In the standard BBN, the primordial plasma is assumed to be ideal, with particles and photons satisfying the Maxwell-Boltzmann and Planck distribution, respectively. We suggest that this assumption of the primordial plasma being ideal might oversimplify the early Universe and cause the lithium problem. We find that a deviation of photon distribution from the Planck distribution, which is parameterised with the help of Tsallis statistics, can resolve the primordial lithium problem when the particle distributions of the primordial plasma still follow the Maxwell-Boltzmann distribution. We discuss how the primordial plasma can be weakly non-ideal in this specific fashion and its effects on the cosmic evolution.