Admixture Of States Research Articles

Cationic or Neutral: Dependence of Photophysical Properties of Bis-Alkynylphosphonium Pt(II) Complexes on Ancillary Ligand.

A series of D-π-A alkynylphosphonium salts with different linker between donor and acceptor groups was used to synthesize two series of trans-bis-alkynylphosphonium Pt(II) complexes with different ancillary ligands (triphenylphosphine, P series, and cyanide, CN series). The nature of the ancillary ligand manages the overall charge and emission properties of the complexes obtained. In addition, the variation of the linker in alkynylphosphonium ligands allows fine-tuning the luminescence wavelength. Dicationic series P is unstable in solution under UV excitation, whereas in the solid state, these complexes are the first example of phosphorescent trans-phosphine-bis-alkynyl Pt(II) compounds. Neutral series CN demonstrates bright emission in solution, including dual emission for 2CN complex with biphenyl linker in alkynylphosphonium ligand. However, in the solid state for the CN series drastic decrease in the emission quantum yield compared to the P series was observed. DFT calculations reveal the complicated emission nature for the both P and CN series with various contributions of 3ILCT, 3LLCT and 3MLCT states. However, in the naphthyl-containing derivatives 3P and 3CN, the dominating 3LC character with some admixture of CT states is postulated.

Effect of lattice distortion on spin admixture and quantum transport in organic devices with spin–orbit coupling

Abstract With an extended Su–Schrieffer–Heeger model and Green’s function method, the spin–orbit coupling (SOC) effects on spin admixture of electronic states and quantum transport in organic devices are investigated. The role of lattice distortion induced by the strong electron–lattice interaction in organics is clarified in contrast with a uniform chain. The results demonstrate an enhanced SOC effect on the spin admixture of frontier eigenstates by the lattice distortion at a larger SOC, which is explained by the perturbation theory. The quantum transport under the SOC is calculated for both nonmagnetic and ferromagnetic electrodes. A more notable SOC effect on total transmission and current is observed for ferromagnetic electrodes, where spin filtering induced by spin-flipped transmission and suppression of magnetoresistance are obtained. Unlike the spin admixture, a stronger SOC effect on transmission exists for the uniform chain rather than the organic lattices with distortion. The reason is attributed to the modified spin-polarized conducting states in the electrodes by lattice configuration, and hence the spin-flip transmission, instead of the spin admixture of eigenstates. This work is helpful to understand the SOC effect in organic spin valves in the presence of lattice distortion.

Exploring the vibrational series of pure trilobite Rydberg molecules

In trilobite Rydberg molecules, an atom in the ground state is bound by electron-atom scattering to a Rydberg electron that is in a superposition of high angular momentum states. This results in a homonuclear molecule with a permanent electric dipole moment in the kilo-debye range. Trilobite molecules have previously been observed only with admixtures of low-l states. Here we report on the observation of two vibrational series of pure trilobite Rubidium-Rydberg molecules that are nearly equidistant. They are produced by three-photon photoassociation and lie energetically more than 15 GHz below the atomic 22F state of rubidium. We show that these states can be used to measure the electron-atom scattering length at low energies in order to benchmark current theoretical calculations. In addition to measuring their kilo-Debye dipole moments, we also show that the molecular lifetime is increased compared to the 22F state due to the high-l character. The observation of an equidistant series of vibrational states opens the way to observe coherent molecular wave packet dynamics.

Irreversible metamagnetic transitions in Yb3+ distorted tetragonal Pr0.45Sr0.55MnO3

Field-induced metamagnetic behavior and orbital-ordering (OO) in Yb-substituted (PrSr)MnO3 perovskites have been reported. The occurrence of distortions in the tetragonal crystal lattice leads to a reduction in the bond angle, which in turn governs the temperature and field-dependent long-range magnetic orderings. Extensive magnetization measurements reveal the high Curie temperature ∼ 302 K ferromagnetic (FM) phase and suggest the possibility of the existence of the OO in Pr0.45–x Yb x Sr0.55MnO3 accompanied by antiferromagnetic (AFM) Néel temperature, , as low as 158 K. Irreversible metamagnetic transitions from the AFM phase to the FM phase occur for a specific composition x = 0.05 (Yb5) until ⩽ 220 K. The admixture of AFM and FM metastable states is quite robust in the investigated system, whereas the AFM state is mediated by Yb3+ ions, while the FM state arises as a result of field-driven thermo-magnetic kinetics. These results provide a constructive approach for designing novel spin-valve devices.

Benzimidazole-diamide (bida) Pincer Chromium Complexes: Structures and Reactivity.

Serendipitous discovery of bida (i.e., N1-Ar-N2-((1-Ar-1-benzo[d]imidazol-2-yl)methyl)benzene-1,2-diamide; Ar = 2,6-iPr-C6H3), a potentially redox noninnocent, hemilabile pincer ligand with a methylene group that may facilitate proton/H atom reactivity, prompted its investigation. Chromium was chosen for study due to its multiple stable oxidation states. Disodium salt (bida)Na2(THF)n was prepared by thermal rearrangement of (dadi)Na2(THF)4 (i.e., (N,N'-di-2-(2,6-diisopropylphenylamine)phenylglyoxaldiimine)-Na2(THF)4). Salt metathesis of (bida)Na2(THF)n (generated in situ) with CrCl3(THF)3 or Cl3V═NAr (Ar = 2,6-iPr2C6H3) afforded (bida)CrCl(THF) (1-THF) and (bida)ClV═NAr, respectively. Substitutions provided (bida)CrCl(PMe2Ph) (1-PMe2Ph) and (bida)CrR(THF) (2-R, where R = Me, CH2CMe2Ph (Nph)). Oxidation of 1-THF with ArN3 (Ar = 2,6-iPr2C6H3) or AdN3 (Ad = 1-adamantyl) generated (bida)ClCr═NAr (3═NAr) and (bida)ClCr═NAd (3═NAd) and subsequent alkylation converted these to (bida)R'Cr═NR (R' = Me, R = Ad, Ar, 5═NR; R' = CH2CMe2Ph (Nph), R = Ad, Ar, 6═NR). In contrast, the addition of AdN3 to 2-Nph gave the insertion product (bida)Cr(κ2-N,N-ArN3Nph) (7). Addition of N-chlorosuccinimide to 1-THF produced (bia)CrCl2(THF) (8), where bia is the pincer derived via hydrogen atom loss from bida methylene. A similar HAT afforded (bia)ClCr(CNAr')2 (9, Ar' = 2,6-Me2C6H3) when 3═NAd was exposed to Ar'NC. An empirical equation of charge was applied to each bida species, whose metric parameters are unchanging despite formal oxidation state conversions from Cr(III) to Cr(V). Calculations and Mulliken spin density assessments reveal several situations in which antiferromagnetic (AF) coupling and admixtures of integer ground states (GSs) describe a complicated electronic structure.

Bichromatic Imaging of Single Molecules in an Optical Tweezer Array.

We report on a novel bichromatic fluorescent imaging scheme for background-free detection of single CaF molecules trapped in an optical tweezer array. By collecting fluorescence on one optical transition while using another for laser cooling, we achieve an imaging fidelity of 97.7(2)% and a nondestructive detection fidelity of 95.5(6)%. Notably, these fidelities are achieved with a modest photon budget, suggesting that the method could be extended to more complex laser-coolable molecules with less favorable optical cycling properties. We also report on a framework and new methods to characterize various loss mechanisms that occur generally during fluorescent detection of trapped molecules, including two-photon decay and admixtures of higher excited states that are induced by the trapping light. In particular, we develop a novel method to dispersively measure transition matrix elements between electronically excited states. The method could also be used to measure arbitrarily small Franck-Condon factors between electronically excited states, which could significantly aid in ongoing efforts to laser cool complex polyatomic molecules.

Probing the incoherent admixture of low and high-spin states of Co in (LaPr)CoO3 perovskite: focus on structural phase transitions

We report the mixed valence and intermediate spin-state (IS) transitions in Pr substituted LaCoO3 perovskites in the form of bulk and nanostructures. Various compositions (x) of La1−x Pr x CoO3 (0 ⩽ x⩽ 0.9) were synthesized using the sol–gel process under moderate heat treatment conditions (600 °C). The structural analysis of these compounds reveals a phase crossover from the monoclinic phase (space group, s.g.: I2/a) to an orthorhombic one (s.g.: Pbnm), and a rhombohedral phase (s.g.: R-3c) to an orthorhombic one (s.g.: Pnma) in the bulk and nanostructures, respectively, for the composition range 0 ⩽ x⩽ 0.6. Such a structural transformation remarkably reduces the Jahn–Teller distortion factor ΔJT: 0.374 → 0.0016 signifying the dominant role of the IS state (S Avg = 1) of trivalent Co ions in the investigated system. Magnetization measurements reveal the ferromagnetic (FM) nature of bulk LaCoO3 along with a weak antiferromagnetic (AFM) component coexisting with an FM component. This coexistence results in a weak loop-asymmetry (zero-field exchange-bias effect ∼134 Oe) at low temperatures. Here the FM ordering occurs due to the double-exchange interaction (J EX /k B∼ 11.25 K) between the tetravalent and trivalent Co ions. Significant decrease in the ordering temperatures was noticed in the nanostructures (T C ∼ 50 K) as compared to the bulk counterpart (∼90 K) due to the finite size/surface effects in the pristine compound. However, the incorporation of Pr leads to the development of a strong AFM component (J EX/k B ∼ 18.2 K) and enhances the ordering temperatures (∼145 K for x = 0.9) with negligible FM correlations in both bulk and nanostructures of LaPrCoO3 due to the dominant super-exchange interaction: Co3+/4+‒O‒Co3+/4+. Further evidence of the incoherent mixture of low-spin (LS) and high-spin (HS) states comes from the M–H measurements which yields a saturation magnetization of M S ∼ 275 emu mol−1 (under the limit of 1/H → 0) consistent with the theoretical value of 279 emu mol−1 corresponding to the spin admixture: 65% LS + 10% IS of trivalent Co along with 25% of LS Co4+ in the bulk pristine compound. A similar analysis yields: Co3+ [30% LS + 20% IS] + Co4+ [50% of LS] for the nanostructures of LaCoO3, yet the Pr substitution decreases the spin admixture configuration. The Kubelka–Munk analysis of the optical absorbance results in a significant decrease in the optical energy band gap (E g:1.86 → 1.80 eV) with the incorporation of Pr in LaCoO3 which corroborates the above results.

Thermodynamics and a definite large half-metallic spin gap along with a magnetic anisotropy in La-doped Ba[formula omitted]NiIrO[formula omitted

Electron doping (i. e., by replacing Ba+2 with La+3) impact on the electronic and magnetic properties of Ba2NiIrO6 system is investigated using ab-initio calculations with the inclusion of Hubbard parameter U along with spin–orbit coupling effects. The calculated formation energies affirm the experimental realization of all motifs at ambient conditions. Whereas, the elastic properties confirm the mechanical stability, ductility, and thermal conductivity of all the structures. It is revealed that anti-ferromagnetic/ferromagnetic (FM) interaction between Ni and Ir ions are energetically stable in pristine motif having an energy band gap (Eg) of 0.70/0.35 eV using the GGA+U method without/with the inclusion of SOC effects, which is in good agreement with the recent experimental results (Feng et al., 2021). Interestingly, La-doped structures depict the half-metallic FM behavior except for 50% concentration, which results in conductivity of the spin-minority channel owing to the admixture of Ir 5d states. On the other hand, the spin-majority channels exhibit an insulating nature having a large Eg of 2.53/2.63/2.49 eV for 12.5%/25%/37.5%, which looks sufficient to restrict the spin reversal and assure high spin filtering efficiency. Moreover, La-doping leads to the existence of mixed-valence state of ＋6/＋5 having a configuration 5d3 (t2g3↑t2g0↓eg0↑eg0↓)/5d4 (t2g3↑t2g1↓eg0↑eg0↓) for Ir ion. Finally, a reasonable magneto-crystalline anisotropic constant of ∼×106 erg/cm3 in all La-doped Ba2NiIrO6 systems is predicted, which is a good signal for their potential utilization in data storage devices.

Origin of Ferromagnetic Exchange Coupling in Donor–Acceptor Biradical Analogues of Charge-Separated Excited States

A new donor-acceptor biradical complex, TpCum,MeZn(SQ-VD) (TpCum,MeZn+ = zinc(II) hydro-tris(3-cumenyl-5-methylpyrazolyl)borate complex cation; SQ = orthosemiquinone; VD = oxoverdazyl), which is a ground-state analogue of a charge-separated excited state, has been synthesized and structurally characterized. The magnetic exchange interaction between the S = 1/2 SQ and the S = 1/2 VD within the SQ-VD biradical ligand is observed to be ferromagnetic, with JSQ-VD = +77 cm-1 (H = -2JSQ-VDŜSQ·ŜVD) determined from an analysis of the variable-temperature magnetic susceptibility data. The pairwise biradical exchange interaction in TpCum,MeZn(SQ-VD) can be compared with that of the related donor-acceptor biradical complex TpCum,MeZn(SQ-NN) (NN = nitronyl nitroxide, S = 1/2), where JSQ-NN ≅ +550 cm-1. This represents a dramatic reduction in the biradical exchange by a factor of ∼7, despite the isolobal nature of the VD and NN acceptor radical SOMOs. Computations assessing the magnitude of the exchange were performed using a broken-symmetry density functional theory (DFT) approach. These computations are in good agreement with those computed at the CASSCF NEVPT2 level, which also reveals an S = 1 triplet ground state as observed in the magnetic susceptibility measurements. A combination of electronic absorption spectroscopy and CASSCF computations has been used to elucidate the electronic origin of the large difference in the magnitude of the biradical exchange coupling between TpCum,MeZn(SQ-VD) and TpCum,MeZn(SQ-NN). A Valence Bond Configuration Interaction (VBCI) model was previously employed to highlight the importance of mixing an SQSOMO → NNLUMO charge transfer configuration into the electronic ground state to facilitate the stabilization of the high-spin triplet (S = 1) ground state in TpCum,MeZn(SQ-NN). Here, CASSCF computations confirm the importance of mixing the pendant radical (e.g., VD, NN) LUMO (VDLUMO and NNLUMO) with the SOMO of the SQ radical (SQSOMO) for stabilizing the triplet, in addition to spin polarization and charge transfer contributions to the exchange. An important electronic structure difference between TpCum,MeZn(SQ-VD) and TpCum,MeZn(SQ-NN), which leads to their different exchange couplings, is the reduced admixture of excited states that promote ferromagnetic exchange into the TpCum,MeZn(SQ-VD) ground state, and the intrinsically weaker mixing between the VDLUMO and the SQSOMO compared to that observed for TpCum,MeZn(SQ-NN), where this orbital mixing is significant. The results of this comparative study contribute to a greater understanding of biradical exchange interactions, which are important to our understanding of excited-state singlet-triplet energy gaps, electron delocalization, and the generation of electron spin polarization in both the ground and excited states of (bpy)Pt(CAT-radical) complexes.

On the Cooperative Origin of Solvent-Enhanced Symmetry-Breaking Charge Transfer in a Covalently Bound Tetracene Dimer Leading to Singlet Fission.

Singlet fission in covalently bound acene dimers in solution is driven by the interplay of excitonic and singlet correlated triplet 1(TT) states with intermediate charge-transfer states, a process which depends sensitively on the solvent environment. We use high-level electronic structure methods to explore this singlet fission process in a linked tetracene dimer, with emphasis on the symmetry-breaking mechanism for the charge-transfer (CT) states induced by low-frequency antisymmetric vibrations and polar/polarizable solvents. A combination of the second-order algebraic diagrammatic construction (ADC(2)) and density functional theory/multireference configuration interaction (DFT/MRCI) methods are employed, along with a state-specific conductor-like screening model (COSMO) solvation model in the former case. This work quantifies, for the first time, an earlier mechanistic proposal [Alvertis et al., J. Am. Chem. Soc. 2019, 141, 17558] according to which solvent-induced symmetry breaking leads to a high-energy CT state which interacts with the correlated triplet state, resulting in singlet fission. An approximate assessment of the nonadiabatic interactions between the different electronic states underscores that the CT states are essential in facilitating the transition from the bright excitonic state to the 1(TT) state leading to singlet fission. We show that several types of symmetry-breaking inter- and intra-fragment vibrations play a crucial role in a concerted mechanism with the solvent environment and with the symmetric inter-fragment torsion, which tunes the admixture of excitonic and CT states. This offers a new perspective on how solvent-induced symmetry-breaking CT can be understood and how it cooperates with intramolecular mechanisms in singlet fission.

Cation Valences and Multiferroic Properties of EuTiO3 Co-Doped with Ba and Transition Metals of Co/Ni.

Eu1−xBaxTi1−yMyO3 (M = Co or Ni) was sintered at 1400 °C under a reduction atmosphere. X-ray photoelectron spectroscopy revealed the mixed valences of Eu2+/Eu3+ and Ti4+/Ti3+ in EuTiO3 and Eu0.7Ba0.3TiO3, as well as some oxygen vacancies required to keep the charge neutrality. The co-doping of Co2+/Ni2+ in Eu0.7Ba0.3TiO3 resulted in the disappearance of oxygen vacancies, as a result of a reduction in Ti3+ numbers and an increase in Eu3+ numbers. On the other hand, Ba2+ doping led to an increased lattice parameter due to its larger ionic size than Eu2+, whereas the Co2+/Ni2+ co-doping resulted in smaller lattice parameters because of the combined effects of ionic size and variation in the oxygen-vacancy numbers. Eu0.7Ba0.3TiO3 exhibited a clear ferroelectricity, which persisted in the Co2+/Ni2+ co-doped samples until the doping levels of y = 0.05 and 0.10, respectively. Eu0.7Ba0.3TiO3 remained to be antiferromagnetic with a reduced transition temperature of 3.1 K, but co-doping of Co2+/Ni2+ turned the samples from antiferromagnetic to ferromagnetic with transition temperatures of 2.98 K and 2.72 K, respectively. The cause for such a transition could not be explained by the larger lattice volume, oxygen vacancies and mixed valences of Eu2+/Eu3+, which were proposed in previous works. Instead, it was more likely to arise from a large asymmetric distortion of the Eu–O polyhedron introduced by the aliovalent doping, which promotes the admixture of Eu 5d and 4f states.

Magnetic properties of the triangular-lattice antiferromagnets Ba3RB9O18 (R=Yb, Er)

Frustration, spin correlations and interplay between competing degrees of freedom are some of the key ingredients that underlie exotic states with fractional excitations in quantum materials. Rare-earth based two dimensional magnetic lattice wherein crystal electric field, spin-orbit coupling, anisotropy and electron correlation between rare-earth moments offer a new paradigm in this context. Herein, we present crystal structure, magnetic susceptibility and specific heat accompanied by crystal electric field calculations on the polycrystalline sample of Ba3RB9O18 (R = Yb, Er) in which R3+ ions form a perfect triangular lattice without anti-site disorder. The localized R3+ spins show neither long-range order nor spin-glass state down to 1.9 K in Ba3RB9O18. Magnetization data reveal a pseudospin Jeff = 1/2 ( Yb3+) in the Kramers doublet state and a weak antiferromagnetic interaction between Jeff = 1/2 moments in the Yb variant. On the other hand, the effective moment {\mu}eff = 8.8 {\mu}B was obtained from the Curie-Weiss fit of the low-temperature susceptibility data of Er variant suggests the admixture of higher crystal electric field states with the ground state. The Curie-Weiss fit of low-temperature susceptibility data for Er system unveils the presence of a relatively strong antiferromagnetic interaction between Er3+ moments compared to its Yb3+ analog. Ba3ErB9O18 does not show long-range magnetic ordering down to 500 mK. Furthermore, our crystal electric field calculations based on magnetization data of Ba3ErB9O18 suggest the presence of a small gap between the ground and first excited Kramers doublets. The broad maximum around 4 K in magnetic specific heat in zero-field is attributed to the thermal population of the first CEF excited state in Ba3ErB9O18, which is consistent with our CEF calculations.

Exploring optimal multimode vibronic pathways in singlet fission of azaborine analogues of perylene.

The development of new singlet fission chromophores is a vibrant area of research to explore the possibility of efficient photovoltaic devices. Using high-level ab-initio density matrix renormalization group calculations, we present a systematic analysis of BN-doped perylenes for their potential application as singlet fission candidates. Four singlet fission chromophores are identified considering the monomer-based properties and their excitonic characters are further analyzed in a dimer configuration optimized in a six-dimensional space for local maxima of fission rates. Furthermore, a multistate multimode vibronic Hamiltonian is employed to identify intra- and interstate vibrational pathways for excitation energy modulation. Several photophysical properties such as Davydov splitting, activation energy and vibronic admixture of multiexcitonic and charge-transfer states are calculated for physically accessible dimers. The optimal dimer packing results in appropriate vibrational relaxation of singlet fission states and promotes significant population transfer which would be more attenuated without such couplings. This work not only identifies potential singlet fission systems with favorable electronic properties but also highlights the sensitivity of dimer packings with respect to the substitution patterns in singlet fission chromophores.

Esterification reaction of scrap tyre oil blended with alcohol in baffled stirred tank reactors: CFD modeling and simulation

A distinct state admixture can not be formed between triglycerdes and alcohol. Establishment of strring enhances the face connection, response rate and also biodiesel product. In artificial approach, transesterification is generally sustained in stirred tank reactors on examing work of this stirred tank reactors is essential for successful plan, process and optimization. Experiments on inflow-fields and chemical responses are costly and time consuming, and therefore cannot meet this test perfectly. Computational fluid dynamics is another approach to model and simulate the stirred tank (CFD). As a result, computational fluid dynamics was used to simulate a transesterification process. Response rates can be determined in this way by looking at a set of discriminational equations that describe response kinetics. The kinetic model agreed with the attention biographics for the anticipated components, and the mass bit patterns demonstrated successful mixing.

Temperature-induced orbital polarizations and tunable charge dynamics in layered double perovskite thin films

The realization of lead-free all-inorganic perovskites in emergent materials requires an in-depth understanding of strongly correlated systems toward optoelectronics or spintronics applications. Herein, we report the electronic and optical variation of the <111>-oriented layered double perovskites (LDP) family with the formula of Cs4MIIBi2Br12 thin films (where MII: Cu, Mn, Pb, or Sr). The element and shell-specific orbital polarization based on soft X-ray linear dichroism spectroscopy probes the Cs M4,5- and Mn L2,3- edges of Cs4MnBi2Br12 thin films as a function of temperature. A strong reversal orbital polarization at the respective edges at 150 K indicates a thermally induced orbital-selective rearrangement at low temperature. In addition, the valence band analysis indicates different orbital admixtures of Br 4p and MIId states, corroborated by the density functional theory calculations. In terms of the transient charge dynamics, we observe the photoluminescence peak maxima position trend line is shifted toward a longer wavelength. In addition, the longest average lifetime is recorded for Cs4CuBi2Br12 at 27.40 ± 1 μs. As the LDP structural integrity is lead-free, therefore, these all-inorganic perovskites hold promising potentials as sustainable and green materials for photophysics applications.

Narrow-band high-lying excitons\xa0with negative-mass electrons in monolayer WSe2

Monolayer transition-metal dichalcogenides (TMDCs) show a wealth of exciton physics. Here, we report the existence of a new excitonic species, the high-lying exciton (HX), in single-layer WSe2 with an energy of ~3.4 eV, almost twice the band-edge A-exciton energy, with a linewidth as narrow as 5.8 meV. The HX is populated through momentum-selective optical excitation in the K-valleys and is identified in upconverted photoluminescence (UPL) in the UV spectral region. Strong electron-phonon coupling results in a cascaded phonon progression with equidistant peaks in the luminescence spectrum, resolvable to ninth order. Ab initio GW-BSE calculations with full electron-hole correlations explain HX formation and unmask the admixture of upper conduction-band states to this complex many-body excitation. These calculations suggest that the HX is comprised of electrons of negative mass. The coincidence of such high-lying excitonic species at around twice the energy of band-edge excitons rationalizes the excitonic quantum-interference phenomenon recently discovered in optical second-harmonic generation (SHG) and explains the efficient Auger-like annihilation of band-edge excitons.

Integrative Epigenomics Reveals Novel Chronic Lymphocytic Leukemia-Specific Chromatin States Associated with Epigenetic and Transcriptional Heterogeneity

Chronic lymphocytic leukemia (CLL) evolves through progression and relapse. Intra-leukemic epigenetic heterogeneity in DNA methylation (DNAme) has been shown to co-operate with genetic heterogeneity in increasing CLL's evolutionary capacity. However, DNAme constitutes only one layer of epigenetic information. To comprehensively study the epigenetic landscape of CLL and its intra-leukemic heterogeneity, we complemented bisulfite sequencing with RNA-seq and a ChIP-seq compendium of histone modification maps (H3K4me3, H3K27ac, H3K27me3, H3K9me3, H3K36me3) in a cohort of 17 primary CLL and 5 normal B cell samples.Analysis of H3K4me3 and H3K27ac distribution revealed that CLL is associated with greater enhancer activation than normal B cells, with enhanced NFAT, FOXP1, NFkB, and BACH2 activity, as well as downregulated TP53 activity. 1,013 super-enhancers were differentially regulated in CLL compared with normal B cells, with preferential association for genes critical for lymphocyte proliferation and differentiation (including BCL2, TCF/LEF, and EP400) (Figure A).Next, we hypothesized that intra-leukemic admixtures of epigenetic states and stochastic epigenetic changes during CLL evolution, may lead to reduced co-ordination between any two layers of epigenetic or transcriptional information. To assess this, we drew on a fundamental metric in information theory - mutual information (MI) - which measures how much can be learned from one variable about another. Normal B cells exhibited highly coordinated transcriptional regulation, resulting in higher pairwise MI compared with CLL samples. For example, we observed a 13% decrease in DNAme-RNAseq MI in CLL relative to normal B cells, suggesting that stochastic changes and intra-leukemic heterogeneity decreases the MI of these two variables when measured at the population level (Figure B).To extend the evaluation of epigenetic co-ordination beyond mutual information of two variables, we modeled the combinatorial patterns of histone modifications, DNAme, and gene expression using a Dirichlet Process Mixture (DPM), which allows learning de novo the number of combinatorial states. DPM analysis revealed that while in normal B cells the combinatorial chromatin states were generally associated with a uniform transcriptional output, in CLL many of these states were associated with variable expression level. For example, transcription start sites (TSSs) with H3K27me3hi/H3K4me3low/H3K27aclow, that in normal B cells were associated with uniform gene silencing, were 3 times more likely to be associated with gene expression in CLL (P < 0.0001, Figure C).To validate the greater combinatorial epigenetic complexity in CLL, we applied an orthogonal method by training a multivariate Hidden Markov Model (HMM) in CLL and normal B cells. We identified convergence at 12 states(Figure D). HHM distinguished between CLL and normal B cells, with ~20,000 segments assigned to discrepant states between CLL and normal cells, enriched for TP53 regulated genes. Consistent with greater combinatorial complexity, we observed higher within-state variation in CLL, with active TSSs, transcribed regions, and poised TSSs exhibiting the largest fold-change increase in within-state variability (2.7, 2.5, and 1.4, respectively).Interestingly, HMM also revealed a CLL specific state (P < 0.0001) marked by intermediate H3K27ac and H3K27me3, which are typically exclusive. This state was >2-fold more common in CLL than normal B cells. CLL cells harbored ~1.6M segments of this novel state often located at non-first introns and LTRs and distal regulatory elements. Interestingly, these segments, repressed by Polycomb in normal B cells, were also more likely to be reactivated in CLL (OR: 1.98; CI: 1.39-2.82; P < 0.0001), putatively enabling higher MYC activity by motif enrichment analysis (Figure D-inset).Thus, CLL's epigenetic landscape is marked by decreased co-ordination between different layers of the epigenome. Our data suggest that ongoing diversification of the CLL cell population leads to an admixture of cells with diverging epigenetic identities, resulting in incomplete gene silencing by the Polycomb complex, and unexpected co-occurrence of, typically mutually exclusive, activating and repressing histone modifications. [Display omitted] DisclosuresLandau:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees.

Measurement of CP observables in B\xb1 \u2192 D(*)K\xb1 and B\xb1 \u2192 D(*)\u03c0\xb1 decays using two-body D final states

Measurements of CP observables in B± → D(*)K± and B± → D(*)π± decays are presented, where D(∗) indicates a neutral D or D∗ meson that is an admixture of meson and anti-meson states. Decays of the D(∗) meson to the Dπ0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon. Decays of the D meson are reconstructed in the K±π∓, K+K−, and π+π− final states. The analysis uses a sample of charged B mesons produced in proton-proton collisions and collected with the LHCb experiment, corresponding to integrated luminosities of 2.0, 1.0, and 5.7 fb−1 taken at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The measurements of partially reconstructed B± → D(*)K± and B± → D(∗)π± with D → K∓π± decays are the first of their kind, and a first observation of the B± → {left(D{pi}^0right)}_{D^{ast }}{pi}^{pm } decay is made with a significance of 6.1 standard deviations. All CP observables are measured with world-best precision, and in combination with other LHCb results will provide strong constraints on the CKM angle γ.

Light scalar modes from holographic deformations

We consider different ways of modifying the mass spectrum of a strongly coupled gauge theory with confinement using the AdS/CFT correspondence. Single- and multitrace deformations are introduced, such that the resulting theory has a mode lighter than the confinement scale. The multitrace deformation is shown to be a possible way of achieving a light composite mode, unlike the single-trace deformation where the light mode is an admixture of elementary and composite states.

Partially composite Dynamical Dark Matter

In this paper, we consider a novel realization of the Dynamical Dark Matter (DDM) framework in which the ensemble of particles which collectively constitute the dark matter are the composite states of a strongly-coupled conformal field theory. Cosmological abundances for these states are then generated through mixing with an additional, elementary state. As a result, the physical fields of the DDM dark sector at low energies are partially composite -- i.e., admixtures of elementary and composite states. Interestingly, we find that the degree of compositeness exhibited by these states varies across the DDM ensemble. We calculate the masses, lifetimes, and abundances of these states -- along with the effective equation of state of the entire ensemble -- by considering the gravity dual of this scenario in which the ensemble constituents are realized as the Kaluza-Klein states associated with a scalar propagating within a slice of five-dimensional anti-de Sitter (AdS) space. Surprisingly, we find that the warping of the AdS space gives rise to parameter-space regions in which the decay widths of the dark-sector constituents vary non-monotonically with their masses. We also find that there exists a maximum degree of AdS warping for which a phenomenologically consistent dark-sector ensemble can emerge. Our results therefore suggest the existence of a potentially rich cosmology associated with partially composite DDM.