Miracle-dz/UniFAR-FTUs huggingface dataset:
String condensation: Nemesis of Black Holes?

This paper puts forward a conjecture that there are no black holes in M theory. We will show that a mechanism to prevent black hole formation is needed in 4 dimensions to make string theory a viable high energy model of quantum gravity. Black hole formation may be averted by a gravity regulation mechanism based on string condensation. In this scenario, black holes are replaced by ‘hot holograms’ that form during gravitational collapse. The geometric conditions based on the properties of free thermalon solutions that are proposed for conversion to a high temperature hologram to occur, however, are local and generic in dimension and could apply throughout M space. This idea can be applied to resolve the problems presented by the process of black hole evaporation, which appears to be inconsistent with quantum information theory. Whereas, in the conventional view, black holes are real and firewalls are probably a chimera, in the scenario proposed here that situation would be reversed.
NEPTUNE'S WILD DAYS: CONSTRAINTS FROM THE ECCENTRICITY DISTRIBUTION OF THE CLASSICAL KUIPER BELT

Neptune's dynamical history shaped the current orbits of Kuiper Belt objects (KBOs), leaving clues to the planet's orbital evolution. In the “classical” region, a population of dynamically “hot” high-inclination KBOs overlies a flat “cold” population with distinct physical properties. Simulations of qualitatively different histories for Neptune, including smooth migration on a circular orbit or scattering by other planets to a high eccentricity, have not simultaneously produced both populations. We explore a general Kuiper Belt assembly model that forms hot classical KBOs interior to Neptune and delivers them to the classical region, where the cold population forms in situ. First, we present evidence that the cold population is confined to eccentricities well below the limit dictated by long-term survival. Therefore, Neptune must deliver hot KBOs into the long-term survival region without excessively exciting the eccentricities of the cold population. Imposing this constraint, we explore the parameter space of Neptune's eccentricity and eccentricity damping, migration, and apsidal precession. We rule out much of parameter space, except where Neptune is scattered to a moderately eccentric orbit (e > 0.15) and subsequently migrates a distance ΔaN = 1–6 AU. Neptune's moderate eccentricity must either damp quickly or be accompanied by fast apsidal precession. We find that Neptune's high eccentricity alone does not generate a chaotic sea in the classical region. Chaos can result from Neptune's interactions with Uranus, exciting the cold KBOs and placing additional constraints. Finally, we discuss how to interpret our constraints in the context of the full, complex dynamical history of the solar system.
Vacua Morghulis

We conjecture that all vacua in string theory decay. More precisely, non-supersymmetric vacua in string theory are at most metastable and eventually decay, while supersymmetric vacua are only marginally stable. All de Sitter vacua with small cosmological constant are metastable to decay via a process that occurs on scales small compared to the horizon size.
Science with the space-based interferometer eLISA. III: probing the expansion of the universe using gravitational wave standard sirens

We investigate the capability of various configurations of the space interferometer eLISA to probe the late-time background expansion of the universe using gravitational wave standard sirens. We simulate catalogues of standard sirens composed by massive black hole binaries whose gravitational radiation is detectable by eLISA, and which are likely to produce an electromagnetic counterpart observable by future surveys. The main issue for the identification of a counterpart resides in the capability of obtaining an accurate enough sky localisation with eLISA. This seriously challenges the capability of four-link (2 arm) configurations to successfully constrain the cosmological parameters. Conversely, six-link (3 arm) configurations have the potential to provide a test of the expansion of the universe up to z ∼ 8 which is complementary to other cosmological probes based on electromagnetic observations only. In particular, in the most favourable scenarios, they can provide a significant constraint on H0 at the level of 0.5%. Furthermore, (ΩM, ΩΛ) can be constrained to a level competitive with present SNIa results. On the other hand, the lack of massive black hole binary standard sirens at low redshift allows to constrain dark energy only at the level of few percent.
CARNEGIE HUBBLE PROGRAM: A MID-INFRARED CALIBRATION OF THE HUBBLE CONSTANT

Using a mid-infrared calibration of the Cepheid distance scale based on recent observations at 3.6 μm with the Spitzer Space Telescope, we have obtained a new, high-accuracy calibration of the Hubble constant. We have established the mid-IR zero point of the Leavitt law (the Cepheid period–luminosity relation) using time-averaged 3.6 μm data for 10 high-metallicity, Milky Way Cepheids having independently measured trigonometric parallaxes. We have adopted the slope of the PL relation using time-averaged 3.6 μm data for 80 long-period Large Magellanic Cloud (LMC) Cepheids falling in the period range 0.8 < log(P) < 1.8. We find a new reddening-corrected distance to the LMC of 18.477 ± 0.033 (systematic) mag. We re-examine the systematic uncertainties in H0, also taking into account new data over the past decade. In combination with the new Spitzer calibration, the systematic uncertainty in H0 over that obtained by the Hubble Space Telescope Key Project has decreased by over a factor of three. Applying the Spitzer calibration to the Key Project sample, we find a value of H0 = 74.3 with a systematic uncertainty of ±2.1 (systematic) km s−1 Mpc−1, corresponding to a 2.8% systematic uncertainty in the Hubble constant. This result, in combination with WMAP7 measurements of the cosmic microwave background anisotropies and assuming a flat universe, yields a value of the equation of state for dark energy, w0 = −1.09 ± 0.10. Alternatively, relaxing the constraints on flatness and the numbers of relativistic species, and combining our results with those of WMAP7, Type Ia supernovae and baryon acoustic oscillations yield w0 = −1.08 ± 0.10 and a value of Neff = 4.13 ± 0.67, mildly consistent with the existence of a fourth neutrino species.
Re-opening dark matter windows compatible with a diphoton excess

We investigate a simple setup in which an excess in the di-photon invariant mass distribution around 750 GeV, as seen by the ATLAS and CMS collaborations, is originated through a pair of collimated photon pairs. In this framework a scalar state s decays into two light pseudo-Goldstone bosons a, each of which subsequently decays into a pair of collimated photons which are misidentified as a single photon. In a minimal context of spontaneous symmetry breaking, we show that coupling a complex scalar field Φ=(s+ia)/√2 to a fermionic dark matter candidate χ, also responsible for generating its mass, allows for the correct relic density in a large region of the parameter space, while not being excluded by the direct or indirect detection experiments. Moreover, the correct relic abundance can naturally co-exist with a relatively large width for the resonant field s.
A comparative study of AGN feedback algorithms

Modelling AGN feedback in numerical simulations is both technically and theoretically challenging, with numerous approaches having been published in the literature. We present a study of five distinct approaches to modelling AGN feedback within gravitohydrodynamic simulations of major mergers of Milky Way-sized galaxies. To constrain differences to only be between AGN feedback models, all simulations start from the same initial conditions and use the same star formation algorithm. Most AGN feedback algorithms have five key aspects: black hole accretion rate, energy feedback rate and method, particle accretion algorithm, black hole advection algorithm, and black hole merger algorithm. All models follow different accretion histories, with accretion rates that differ by up to three orders of magnitude at any given time. We consider models with either thermal or kinetic feedback, with the associated energy deposited locally around the black hole. Each feedback algorithm modifies the gas properties near the black hole to different extents. The particle accretion algorithms usually (but not always) maintain good agreement between the mass accreted by \dot{M} dt and the mass of gas particles removed from the simulation. The black hole advection algorithms dampen inappropriate dragging of the black holes by two-body interactions. Advecting the black hole a limited distance based upon local mass distributions has many desirably properties. The black holes merge when given criteria are met, and we find a range of merger times for different criteria. Using the M_{BH}-\sigma relation as a diagnostic of the remnants yields three models that lie within the one-sigma scatter of the observed relation and two that fall below it. The wide variation in accretion behaviours of the models reinforces the fact that there remains much to be learnt about the evolution of galactic nuclei. (abridged)
Galaxy Evolution and Star Formation Efficiency at 0.2 < z < 0.6

We present the results of a CO line survey of 30 galaxies at moderate redshift (z \sim 0.2-0.6), with the IRAM 30m telescope, with the goal to follow galaxy evolution and in particular the star formation efficiency (SFE) as defined by the ratio between far-infrared luminosity and molecular gas mass (LFIR/M(H2)). The sources are selected to be ultra-luminous infrared galaxies (ULIRGs), with LFIR larger than 2.8 10^{12} Lsol, experiencing starbursts; adopting a low ULIRG CO-to-H2 conversion factor, their gas consumption time-scale is lower than 10^8 yr. To date only very few CO observations exist in this redshift range that spans nearly 25% of the universe's age. Considerable evolution of the star formation rate is already observed during this period. 18 galaxies out of our sample of 30 are detected (of which 16 are new detections), corresponding to a detection rate of 60%. The average CO luminosity for the 18 galaxies detected is L'CO = 2 10^{10} K km/s pc^2, corresponding to an average H2 mass of 1.6 10^{10} Msol. The FIR luminosity correlates well with the CO luminosity, in agreement with the correlation found for low and high redshift ULIRGs. Although the conversion factor between CO luminosity and H2 mass is uncertain, we find that the maximum amount of gas available for a single galaxy is quickly increasing as a function of redshift. Using the same conversion factor, the SFEs for z\sim 0.2-0.6 ULIRGs are found to be significantly higher, by a factor 3, than for local ULIRGs, and are comparable to high redshift ones. We compare this evolution to the expected cosmic H2 abundance and the cosmic star formation history.
Hubble Space Telescope Observations of M Subdwarfs

We present the results of a Hubble Space Telescope snapshot program to search for very low mass stellar companions to nearby M subdwarfs. None of our nine targetted metal‐poor primaries has companions more massive than the hydrogen burning limit, implying that the halo binary fraction is equal to or less than the Galactic disk binary fraction below 0.3 M⊙. In addition, the more distant tertiary VB 12, an sdM3.0 companion to an F subdwarf double, is also unresolved. We show that the relation between WFPC2 F555W and F850LP photometry and ground‐based V, I photometry is consistent with theoretical expectations. We also report that two recently observed Hyades M dwarfs appear single.
Towards precise relativistic b quarks on the lattice

We discuss the status of our ongoing efforts to improve on our calculation of the Ds decay constant. We show preliminary results on the ratio of the charm to the strange quark mass. We also present preliminary results for spectroscopy, decay const ants and bottom quark mass obtained by performing calculations with highly improved staggered quarks at masses above the c mass and close to the b mass.
A Few Comments On Matlis Duality

For a Noetherian local ring $(R,{\mathfrak m})$ with $\mathfrak p\in \Spec(R)$ we denote $E_R(R/\mathfrak p)$ by the $R$-injective hull of $R/\mathfrak p$. We will show that it has an $\hat{R}^\mathfrak p$-module structure and there is an isomorphism $E_R(R/\mathfrak p)\cong E_{\hat{R}^\mathfrak p}(\hat{R}^\mathfrak p/\mathfrak p\hat{R}^\mathfrak p)$ where $\hat{R}^\mathfrak p$ stands for the $\mathfrak p$-adic completion of $R$. Moreover for a complete Cohen-Macaulay ring $R$ the module $D(E_R(R/\mathfrak p))$ is isomorphic to $\hat{R}_\mathfrak{p}$ provided that $\dim(R/\mathfrak p)=1$ and $D(\cdot)$ denotes the Matlis dual functor $\Hom_R(\cdot, E_R(R/\mathfrak m))$. Here $\hat{R}_\mathfrak{p}$ denotes the completion of ${R_\mathfrak p}$ with respect to the maximal ideal $\mathfrak pR_\mathfrak p$. These results extend those of Matlis (see \cite{m}) shown in the case of the maximal ideal ${\mathfrak m}$.
(309239) 2007 RW10: a large temporary quasi-satellite of Neptune

Upon discovery, asteroid (309239) 2007 RW10 was considered a Neptune Trojan candidate. The object is currently listed by the Minor Planet Center as a Centaur but it is classified as a Scattered Disk or Trans-Neptunian Object by others. Now that its arc-length is 8,154 days and has been observed for more than 20 years, a more robust classification should be possible. Here we explore the orbital behaviour of this object in order to reveal its current dynamical status; we perform N-body simulations in both directions of time to investigate the evolution of its orbital elements. In particular, we study the librational properties of the mean longitude that currently librates around the value of the mean longitude of Neptune with an amplitude of nearly 50 degrees and a period of about 7,500 years. Our calculations show that it has been in its present dynamical state for about 12,500 years and it will stay there for another 12,500 years. Therefore, its current state is relatively short-lived. Due to its chaotic behaviour, the object may have remained in the 1:1 mean motion resonance with Neptune for several 100,000 years at most, undergoing transitions between the various resonant states. (309239) 2007 RW10 is currently a quasi-satellite, the first object of this dynamical class to be discovered around Neptune. With a diameter of about 250 km, it is the largest known co-orbital in the Solar System. Its significant eccentricity (0.30) and orbital inclination (36 degrees), strongly suggest that it did not form in situ but was captured, likely from beyond Neptune. With an apparent magnitude of 21.1 at opposition (October), it is well suited for spectroscopic observations that may provide information on its surface composition and hence eventually its origin.
Evolution of thermally pulsing asymptotic giant branch stars – II. Dust production at varying metallicity

We present the dust ejecta of the new stellar models for the Thermally Pulsing Asymptotic Giant Branch (TP-AGB) phase computed with the COLIBRI code. We use a formalism of dust growth coupled with a stationary wind for both M and C-stars. In the original version of this formalism, the most efficient destruction process of silicate dust in M-giants is chemisputtering by H2 molecules. For these stars we find that dust grains can only form at relatively large radial distances (r~5 R*), where they cannot be efficiently accelerated, in agreement with other investigations. In the light of recent laboratory results, we also consider the alternative case that the condensation temperature of silicates is determined only by the competition between growth and free evaporation processes (i.e. no chemisputtering). With this latter approach we obtain dust condensation temperatures that are significantly higher (up to Tcond~1400 K) than those found when chemisputtering is included (Tcond~900 K), and in better agreement with condensation experiments. As a consequence, silicate grains can remain stable in inner regions of the circumstellar envelopes (r~2 R*), where they can rapidly grow and can be efficiently accelerated. With this modification, our models nicely reproduce the observed trend between terminal velocities and mass loss rates of Galactic M-giants. For C-stars the formalism is based on the homogeneous growth scheme where the key role is played by the carbon over oxygen excess. The models reproduce fairly well the terminal velocities of Galactic stars and there is no need to invoke changes in the standard assumptions. At decreasing metallicity the carbon excess becomes more pronounced and the efficiency of dust formation increases. This trend could be in tension with recent observational evidence in favour of a decreasing efficiency, at decreasing metallicity.
Asteroseismology of the DBV star CBS 114

Asteroseismology is a unique and powerful tool to investigate the internal structure of stars. CBS 114 is the sixth known pulsating DBV star. It was observed by Handler, Metcalfe, & Wood at the South African Astronomical Observatory over three weeks in 2001. Then, it was observed by Metcalfe et al. for seven nights (2004 Feb. 19–25) on the 1.8 m telescope at the Bohyunsan Optical Astronomy Observatory and seven nights (2004 Feb. 21–27) on the 2.1 m telescope at the McDonald Observatory. Totally two triplets, four doublets, and five singlets were identified. The frequency splitting values are very different, from 5.2 μHz to 11.9 μHz, which may reflect differential rotations. We evolve grids of white dwarf models by MESA. Cores, added with He/C envelopes, of those white dwarf models are inserted into WDEC to evolve grids of DBV star models. With those DBV star models, we calculate eigenperiods. Those calculated periods are used to fit observed periods. A best-fitting model is selected. The parameters are Teff = 25000 K, M* = 0.740 M⊙ and log(MHe/M*) = —4.5. With the relatively large stellar mass, the effective temperature is close to the previous spectroscopic result. In addition, kinetic energy distributions are calculated for the best-fitting model. We find that the observed modes with large frequency splitting values are fitted by the calculated modes with a large amount of kinetic energy distributed in the C/O core. After preliminary analysis, we suggest that the C/O core may rotate at least two times faster than the helium layer for CBS 114.
ATCA OBSERVATIONS OF SiO MASERS IN THE GALACTIC CENTER

We present the Australia Telescope Compact Array observations of the SiO masers in the Galactic center (GC) in transitions of v = 1, J = 2-1 at 86 GHz and v = 1, J = 1-0 at 43 GHz. Two 86 GHz SiO masers were detected within the central parsec, and they are associated with IRS 10EE and IRS 15NE, respectively. We detected eighteen 43 GHz SiO masers within a projected separation of ≲2 pc from Sagittarius A*, among which seven masers are newly discovered from our observations. This raises the total number of 43 GHz SiO masers within the central 4 pc of the GC region to 22. Simultaneous observations at 86 and 43 GHz showed that the intensity of 43 GHz SiO maser is ∼3 times higher than that of 86 GHz maser in IRS 10EE (an OH/IR star), while the integrated flux of the SiO maser emission at 43 GHz is comparable with that at 86 GHz in IRS 15NE (an ordinary Mira variable). These results are consistent with previous observations of massive late-type stars in the Galaxy in which the 86 GHz SiO maser is in general weaker than the 43 GHz SiO maser in OH/IR stars, while the two transitions are comparably strong in Mira stars.
Optomechanics with Levitating Dielectrics: Theory and Protocols

This thesis focuses on cavity optomechanics with an optically levitated dielectric object. We develop the underlying theory and propose and analyze various protocols to prepare these macroscopic systems in superposition states. Optical levitation circumvents the direct thermal coupling of the mechanical oscillator to its environment and holds the promise to enable ground-state cooling even at room temperature. This thesis approaches this novel optomechanical system from two different angles reflected in the division into the main parts of Theory and Protocols. In the first part of the thesis, we derive a theoretical description of the system from first principles. A master equation describing the interaction of light with dielectric objects of arbitrary sizes and shapes is developed. It does not rely on the point-particle approximation by taking into account scattering processes to all orders in perturbation theory and treats both the motion of the object and the light quantum-mechanically. This formalism extends the standard master-equation approach to the case where interactions among different modes of the environment are considered. We apply this general method to the specific setup of levitating dielectrics in optical cavities. Apart from photon scattering, we also take into account various other dissipation processes, e.g., blackbody radiation, scattering of gas molecules, or coupling to internal vibrational modes, and compare them to the coherent coupling rates of the system. To analyze the feasibility of ground-state cooling, we derive the steady-state phonon numbers without relying on resolved-sideband or bad-cavity approximations. Within this theoretical framework, the optomechanical performance for realistic experimental parameters is analyzed. We show that cavity cooling of the center-of-mass (cm) mode to the motional ground state is possible for spheres with radius R . 260nm. The focus of the second part of the thesis is to provide protocols for the preparation of the mechanical oscillator in nonclassical states. The realization of superposition states is essential to most of the proposed applications of nano-mechanical oscillators, i.e., for sensing or to find an answer to foundational questions. We confront this problem from three different angles. First, we propose several state-preparation protocols relying on the efficient coupling to single photons, thus projecting their nonclassical
A kind of linearity-invariance under homotopy and some simple applications o fit in mechanics

Neither numerical techniques nor analytical methods of nonlinear problems are satisfactory. The iterative techniques are sensitive not only to the initial solutions but also to the number of unknowns. On the other side, perturbation expansion method depends upon small or great parameters. These limit their applications. This paper is a prelimilary attempt to improve both analytical and numerical techniques of general nonlinear problems, i.e., to overcome the limitations of perturbation methods and iterative techniques described above. Based on a kind of linear property of continuous mapping ( mathematically speaking, a kind of linearity-invariance under homotopy), a kind of analytical method for non linear problems, namely, Process Analysis Method, is described, which does not depend upon small or great parameters. And based on the same property of continuous mapping (homotopy), a kind of numerical technique, called Finite Process Method, is developed, which can avoid the use of iterative techniques to solve non linear problems. The essence of solving nonlinear problems and the differences and relations of linear and nonlinear problems are also simply discussed. Some simple nonlinear problems in mechanics, for instance, the falling of a ball in fluid, the motion of a simple pendulum, 2D nonlinear water waves and so on, are used to introduce and examine the both methods.