Miracle-dz/UniFAR-FTUs huggingface dataset:
Analysis of quantum coherence in bismuth-doped silicon: A system of strongly coupled spin qubits

There is a growing interest in bismuth-doped silicon (Si:Bi) as an alternative to the well-studied proposals for silicon-based quantum information processing (QIP) using phosphorus-doped silicon (Si:P). We focus here on the implications of its anomalously strong hyperfine coupling. In particular, we analyze in detail the regime where recent pulsed magnetic resonance experiments have demonstrated the potential for orders of magnitude speedup in quantum gates by exploiting transitions that are electron paramagnetic resonance (EPR) forbidden at high fields. We also present calculations using a phenomenological Markovian master equation, which models the decoherence of the electron spin due to Gaussian temporal magnetic field perturbations. The model quantifies the advantages of certain "optimal working points" identified as the df/dB=0 regions, where f is the transition frequency, which come in the form of frequency minima and maxima. We show that at such regions, dephasing due to the interaction of the electron spin with a fluctuating magnetic field in the z direction (usually adiabatic) is completely removed. © 2012 American Physical Society.
The Radio Emission, X-Ray Emission, and Hydrodynamics of G328.4+0.2: A Comprehensive Analysis of a Luminous Pulsar Wind Nebula, Its Neutron Star, and the Progenitor Supernova Explosion

We present new observational and modeling results obtained for the Galactic nonthermal radio source G328.4+0.2. Using X-ray data obtained by XMM-Newton, we confirm that its X-ray emission is heavily absorbed, has a spectrum best fitted by a power-law model of photon index Γ = 2 with no evidence for a thermal component, comes from a region significantly smaller than the radio emission, and that the X-ray and radio emissions are significantly offset from each other. We also present the results of a new high-resolution (7'') 1.4 GHz image of G328.4+0.2 obtained using ATCA and a deep search for radio pulsations using the Parkes radio telescope. By comparing this 1.4 GHz image with a similar resolution image at 4.8 GHz, we find that the radio emission has a flat spectrum (α ≈ 0; Sν ∝ να). Additionally, we are able to limit the pseudoluminosity of any pulsar to L1400 ≡ S1400400d2 ≲ 30 mJy kpc2 for the central radio pulsar, assuming a distance of 17 kpc. In light of these observational results, we test whether G328.4+0.2 is a pulsar wind nebula or an SNR that contains a large pulsar wind nebula using a simple hydrodynamic model for the evolution of a pulsar wind nebula inside an SNR. As a result of this analysis, we conclude that G328.4+0.2 is a young (≲10,000 years old) pulsar wind nebula formed by a low magnetic field (≲1012 G) neutron star born spinning rapidly (≲10 ms) expanding into an undetected SNR formed by an energetic (≳1051 ergs), low ejecta mass (Mej ≲ 5 M☉) supernova explosion that occurred in a low-density (n ~ 0.03 cm-3) environment.
VARIABILITY SURVEY IN THE CoRoT SRa01 FIELD: IMPLICATIONS OF ECLIPSING BINARY DISTRIBUTION ON CLUSTER FORMATION IN NGC 2264

Time-series photometry of the CoRoT field SRa01 was carried out with the Berlin Exoplanet Search Telescope II in 2008/2009. A total of 1161 variable stars were detected, of which 241 were previously known and 920 are newly found. Several new, variable young stellar objects have been discovered. The study of the spatial distribution of eclipsing binaries revealed the higher relative frequency of Algols toward the center of the young open cluster NGC 2264. In general Algol frequency obeys an isotropic distribution of their angular momentum vectors, except inside the cluster, where a specific orientation of the inclinations is the case. We suggest that we see the orbital plane of the binaries almost edge-on.
Classical nature of ordered quantum phases and origin of spontaneous symmetry breaking

We analyse the nature of spontaneous symmetry breaking in complex quantum systems by investigating the long-standing conjecture that the maximally symmetry-breaking quantum ground states are the most classical ones corresponding to a globally ordered phase. We make this argument quantitatively precise by comparing different local and global indicators of classicality and quantumness, respectively in symmetry-breaking and symmetry-preserving quantum ground states. We first discuss how naively comparing local, pairwise entanglement and discord apparently leads to the opposite conclusion. Indeed, we show that in symmetry-preserving ground states the two-body entanglement captures only a modest portion of the total two-body quantum correlations, while, on the contrary, in maximally symmetry-breaking ground states it contributes the largest amount to the total two-body quantum correlations. We then put to test the conjecture by looking at the global, macroscopic correlation properties of quantum ground states. We prove that the ground states which realize the maximum breaking of the Hamiltonian symmetries, associated to a globally ordered phase, are the only ones that: I) are always locally convertible, i.e. can be obtained from all other ground states by only applying LOCC transformations (local operations and classical communication), while the reverse is never possible; II) minimize the monogamy inequality on the globally shared, macroscopic bipartite entanglement.
Lithographically and electrically controlled strain effects on anisotropic magnetoresistance in (Ga,Mn)As

It has been demonstrated that magnetocrystalline anisotropies in (Ga,Mn)As are sensitive to lattice strains as small as 10−4 and that strain can be controlled by lattice parameter engineering during growth, through post-growth lithography, and electrically by bonding the (Ga,Mn)As sample to a piezoelectric transducer (PZT). In this work, we show that analogous effects are observed in crystalline components of the anisotropic magnetoresistance (AMR). Lithographically or electrically induced strain variations can produce crystalline AMR components which are larger than the crystalline AMR and a significant fraction of the total AMR of the unprocessed (Ga,Mn)As material. In these experiments, we also observe new higher order terms in the phenomenological AMR expressions which were previously unnoticed in (Ga,Mn)As. It is demonstrated that strain variation effects can play an important role in the magnetotransport characteristics of (Ga,Mn)As lateral nanoconstrictions.
Einstein submanifolds with flat normal bundle in space forms are holonomic

A well-known result asserts that any isometric immersion with flat normal bundle of a Riemannian manifold with constant sectional curvature into a space form is (at least locally) holonomic. In this note, we show that this conclusion remains valid for the larger class of Einstein manifolds. As an application, when assuming that the index of relative nullity of the immersion is a positive constant we conclude that the submanifold has the structure of a generalized cylinder over a submanifold with flat normal bundle.
Genomic insights into antibiotic-resistance and virulence genes of Enterococcus faecium strains from the gut of Apis mellifera

Enterococcus faecium is a lactic acid bacterium that confers beneficial health effects in humans. However, lately, a number of E. faecium strains have been linked to the spread of nosocomial infections in the hospital environment. Therefore, any potential commercial usage of E. faecium isolates should be preceded by an assessment of infection risk. In the current study, the genomes of two novel E. faecium strains Am1 (larval isolate) and Bee9 (adult bee isolate) isolated from the gut of Apis mellifera L. (honeybee) were sequenced to allow evaluation of their safety. In particular, their genomes were screened for antibiotic-resistance and virulence genes. In addition, their potential to spread resistance in the environment was evaluated. The analysis revealed that Am1 and Bee9 possess 2832 and 2844 protein-encoding genes, respectively. In each case, the genome size was 2.7 Mb with a G+C content of 37.9 mol%. Comparative analysis with probiotic, non-pathogenic and pathogenic enterococci revealed that there are variations between the two bee E. faecium isolates and pathogenic genomes. They were, however, closely linked to the probiotic comparison strains. Phenotypically, the Am1 and Bee9 strains were susceptible to most antibiotics tested, but showed intermediate sensitivity towards erythromycin, linezolid and trimethoprim/sulfamethoxazole. Notably, no genes associated with antibiotic resistance in clinical isolates (e.g. vancomycin resistance: vanA, vanB, vanS, vanX and vanY) were present. In addition, the insertion sequences (IS16, ISEfa11 and ISEfa5), acting as molecular pathogenicity markers in clinically relevant E. faecium strains, were also absent. Moreover, the analysis revealed the absence of three key pathogenicity-associated genes (acm, sgrA, ecbA) in the Am1 and Bee9 strains that are found in the prominent clinical isolates DO, V1836, Aus0004 and Aus0085. Overall, the findings of this investigation suggest that the E. faecium isolates from the bee gut have not suffered any recent clinically relevant antibiotic exposure. It also suggests that E. faecium Am1 and Bee9 are safe potential probiotic strains, because they lack the phenotypic and genetic features associated with strains eliciting nosocomial infections.
Fluctuations in strongly coupled cosmologies

In the early Universe, a dual component made of coupled CDM and a scalar field Φ, if their coupling β > (3)1/2/2, owns an attractor solution, making them a stationary fraction of cosmic energy during the radiation dominated era. Along the attractor, both such components expand ∝a−4 and have early density parameters Ωd = 1/(4β2) and Ωc = 2 Ωd (field and CDM, respectively). In a previous paper it was shown that, if a further component, expanding ∝a−3, breaks such stationary expansion at z ∼ 3–5 × 103, cosmic components gradually acquire densities consistent with observations. This paper, first of all, considers the case that this component is warm. However, its main topic is the analysis of fluctuation evolution: out of horizon modes are then determined; their entry into horizon is numerically evaluated as well as the dependence of Meszaros effect on the coupling β; finally, we compute: (i) transfer function and linear spectral function; (ii) CMB Cl spectra. Both are close to standard ΛCDM models; in particular, the former one can be so down to a scale smaller than Milky Way, in spite of its main DM component being made of particles of mass < 1 keV. The previously coupled CDM component, whose present density parameter is 𝒪(10−3), exhibits wider fluctuations δρ/ρ, but approximately β-independent δρ values. We discuss how lower scale features of these cosmologies might ease quite a few problems that ΛCDM does not easily solve.
First-order topological phase transition of the Haldane-Hubbard model

We study the interplay of topological band structure and conventional magnetic long-range order in spinful Haldane model with on-site repulsive interaction. Using the dynamical cluster approximation with clusters of up to 24 sites we find evidence of a first-order phase transition from a Chern insulator at weak coupling to a topologically trivial antiferromagnetic insulator at strong coupling. These results call into question a previously found intermediate state with coexisting topological character and antiferromagnetic long-range order. Experimentally measurable signatures of the first-order transition include hysteretic behavior of the double occupancy, single-particle excitation gap, and nearest neighbor spin-spin correlations. This first-order transition is contrasted with a continuous phase transition from the conventional band insulator to the antiferromagnetic insulator in the ionic Hubbard model on the honeycomb lattice.
The long-term evolution of the X-ray pulsar XTE J1814-338: A receding jet contribution to the quiescent optical emission?

Aims. We present a study of the quiescent optical counterpart of the accreting millisecond X-ray pulsar XTE J1814-338 that is aimed at unveiling the different components, which contribute to the quiescent optical emission of the system. Methods. We carried out multiband (BVR) orbital phase-resolved photometry of the system using the ESO Very Large Telescope (VLT) that is equipped with the FORS2 camera, covering about 70% of the 4.3 hour orbital period. Results. The optical light curves are consistent with a sinusoidal variability that are modulated with an orbital period with a semiamplitude of 0.5−0.7 mag. They show evidence of a strongly irradiated companion star, which agrees with previous findings for this system. However, the observed colours cannot be accounted for by the companion star alone, suggesting the presence of an accretion disc during quiescence. The system seems to be fainter in all analysed bands compared to previous observations. The R band light curve displays a possible phase offset with respect to the B and V band. Through a combined fit of the multi-band light curve performed with a Markov chain Monte Carlo technique, we derive constraints on the companion star, disc fluxes, system distance, and companion star mass. Conclusions. The irradiation luminosity required to account for the observed day-side temperature of the companion star is consistent with the spin-down luminosity of a millisecond radio pulsar. Compared to our data with previous observations, which were collected over 5 years, the flux decrease and spectral evolution of the observed quiescent optical emission cannot be satisfactorily explained with the combined contribution of an irradiated companion star and of an accretion disc alone. The observed progressive flux decrease as the system gets bluer could be due to a continuum component that evolves towards a lower, bluer spectrum. While most of the continuum component is likely due to the disc, we do not expect it to become bluer in quiescence. Hence, we hypothesize that an additional component, such as synchrotron emission from a jet was significantly contributing in the data obtained earlier during quiescence and then progressively fading or moving its break frequency towards longer wavelengths.
Models of AM CVn star outbursts

Outbursting AM CVn stars exhibit outbursts similar to those observed in different types of dwarf novae. Their light-curves combine the characteristic features of SU UMa, ER UMa, Z Cam, and WZ Sge-type systems but also show a variety of properties never observed in dwarf novae. The compactness of AM CVn orbits and their unusual chemical composition make these systems valuable testbeds for outburst models. We aim for a better understanding of the role of helium in the accretion disc instability mechanism, testing the model for dwarf novae outbursts in the case of AM CVn stars, and aim to explain the outburst light-curves of these ultra-compact binaries. We calculated the properties of the hydrogen-free AM CVn stars using our previously developed numerical code adapted to the different chemical composition of these systems and supplemented with formulae accounting for mass transfer rate variations, additional sources of the disc heating, and the primary's magnetic field. We discovered how helium-dominated discs react to the thermal-viscous instability and were able to reproduce various features of the outburst cycles in the light-curves of AM CVn stars. The AM CVn outbursts can be explained by the suitably adapted dwarf-nova disc instability model but, as in the case of its application to hydrogen-dominated cataclysmic variables, one has to resort to additional mechanisms to account for the observed superoutbursts, dips, cycling states, and standstills. We show that the enhanced mass-transfer rate, due presumably to variable irradiation of the secondary, must not only be taken into account but is a determining factor that shapes AM CVn star outbursts. The cause of the variable secondary's irradiation has yet to be understood; the best candidate is the precession of a tilted/warped disc.
Are brood sex ratios adaptive?—The effect of experimentally altered brood sex ratio on nestling growth, mortality and recruitment

Brood sex ratios (BSRs) have often been found to be nonrandom in respect of parental and environmental quality, and many hypotheses suggest that nonrandom sex ratios can be adaptive. To specifically test the adaptive value of biased BSRs, it is crucial to disentangle the consequences of BSR and maternal effects. In multiparous species, this requires cross‐fostering experiments where foster parents rear offspring originating from multiple broods, and where the interactive effect of original and manipulated BSR on fitness components is tested. To our knowledge, our study on collared flycatchers (Ficedula albicollis) is the first that meets these requirements. In this species, where BSRs had previously been shown to be related to parental characteristics, we altered the original BSR of the parents shortly after hatching by cross‐fostering nestlings among trios of broods and examined the effects on growth, mortality and recruitment of the nestlings. We found that original and experimental BSR, as well as the interaction of the two, were unrelated to the fitness components considered. Nestling growth was related only to background variables, namely brood size and hatching rank. Nestling mortality was related only to hatching asynchrony. Our results therefore do not support that the observed BSRs are adaptive in our study population. However, we cannot exclude the possibility of direct effects of experimentally altered BSRs on parental fitness, which should be evaluated in the future. In addition, studies similar to ours are required on various species to get a clearer picture of the adaptive value of nonrandom BSRs.
Discrimination of parametrizations for nuclear effects in neutrino scattering through comparisons of low (̃ 700 MeV) and medium (̃ 3 GeV) energy cross-section data

High-quality charged current quasielastic scattering data have recently been reported for both muon neutrinos and antineutrinos from several accelerator-based neutrino experiments. Measurements from MiniBooNE were the first to indicate that more complex nuclear effects, now thought to be the result of nucleon pair correlations, may contribute to neutrino quasielastic samples at a much higher significance than previously assumed. These findings are now being tested by $\mathrm{MINER}\ensuremath{\nu}\mathrm{A}$ and other contemporary neutrino experiments. Presented here is a comparison of data from MiniBooNE and $\mathrm{MINER}\ensuremath{\nu}\mathrm{A}$ to a few example parametrizations of these nuclear effects. It has been demonstrated that such effects may bias future measurements of neutrino oscillation parameters, and so this issue continues to press the neutrino community. A comparison of data over a large range of neutrino energies is one approach to exploring the extent to which such nucleon correlations may influence our understanding and subsequent modeling of neutrino quasielastic scattering.
Criterion Validity of Protective Behavioral Strategies for Alcohol Consumption among College Students: Comparison across Two Measures

Abstract Background: Protective behavioral strategies (PBS), or behaviors used to reduce harm associated with alcohol use, are often associated with lower levels of alcohol consumption, lower engagement in high-risk drinking behaviors, and fewer alcohol-related consequences. Although the majority of studies have found significant associations between higher PBS use and lower consumption or consequences, some studies have found nonsignificant or even positive associations. One explanatory hypothesis is that the mixed findings are due to differential content in PBS measures. Objectives: The current study examined the criterion validity of two widely-used PBS measures, the PBSS and the SQ. In a multi-institution online study assessing alcohol outcomes, college drinkers were randomly assigned to complete one PBS measure. Both measures had the same response options to standardize assessment and focus on content. Results: Findings suggest both measures of PBS are consistently predictive of alcohol outcomes among college drinkers, across multiple subpopulations (i.e., strength of association was not moderated by sex, race, or drinking level). Conclusions/Importance: Some PBS subscales were more impactful than others, suggesting researchers may want to choose which PBS scale to use based on outcomes of interest, or after determining if alternatives to drinking is an important facet of PBS for the research questions being examined. Moreover, the differential findings for subscales suggest that prevention and intervention programs incorporating PBS should focus on strategies that avoid high-risk scenarios (e.g., avoiding shots or drinking games), rather than general strategies of self-pacing.
Humoral and cellular immunogenicity and efficacy of a coxsackievirus A10 vaccine in mice

ABSTRACT Coxsackievirus A10 (CV-A10) has become one of the major pathogens of hand, foot and mouth disease (HFMD), and studies on the vaccine and animal model of CV-A10 are still far from complete. Our study used a mouse-adapted CV-A10 strain, which was lethal for 14-day-old mice, to develop an infected mouse model. Then this model was employed to establish an actively immunized-challenged mouse model to evaluate the efficacy of a formaldehyde-inactivated CV-A10 vaccine, which was prepared from a Vero cell-adapted strain. CV-A10 vaccine at a dose of 0.5 or 2.0 μg was inoculated intraperitoneally in neonatal Kunming mice on the third and ninth day. Then the mice were challenged on day 14. The survival rate of mice immunized with 0.5 or 2.0 μg vaccine were 90% and 100%, respectively, while all Alum-inoculated mice died. Compared to those in the two vaccinated groups, the Alum-inoculated mice showed severe pathological damage, strong viral protein expression and high viral loads. The antisera from vaccinated mice showed high level of neutralizing antibodies against CV-A10. Meanwhile, three potential T cell epitopes located at the carboxyl-terminal regions of the VP1 and VP3 were identified and exhibited CV-A10 serotype-specific. The humoral and cellular immunogenicity analysis showed that immunization with two doses of the vaccine elicited CV-A10 specific neutralizing antibody and T cell response in BALB/c mice. Collectively, these findings indicated that this actively immunized-challenged mouse model will be invaluable in future studies on CV-A10 pathogenesis and evaluation of vaccine candidates.