ShantanuT01/DACTYL-Pretraining huggingface dataset:
In the last decades the logico-algebraic approach to quantum mechanics turned to be a successful tool to render the quantum mechanical formalism on a steady operationalistic background. The algebraic approach to general relativity first proposed by Geroch is used to build a smearing procedure for events in the quantized theory of spacetime. It stems from the notion of basic algebra which possesses both the differential structure (as functional algebras) and non-commutativity (as algebras of observables in quantum theories). The main essence of this formalism is that it deprives the notion of spacetime as event support of its fundamental status making it relative to the measurement performed. Before the observation is executed, it is pointless to speak of events as points of spacetime: there is no underlying manifold. Only when an eigen-subalgebra of the basic algebra is outlined as eigenstate of the observable, it gives rise to its functional representation on the appropriate set thought of as spacetime.
This paper introduces minimal solvers that jointly solve for radial lens undistortion and affine-rectification using local features extracted from the image of coplanar translated and reflected scene texture, which is common in man-made environments. The proposed solvers accommodate different types of local features and sampling strategies, and three of the proposed variants require just one feature correspondence. State-of-the-art techniques from algebraic geometry are used to simplify the formulation of the solvers. The generated solvers are stable, small and fast. Synthetic and real-image experiments show that the proposed solvers have superior robustness to noise compared to the state of the art. The solvers are integrated with an automated system for rectifying imaged scene planes from coplanar repeated texture. Accurate rectifications on challenging imagery taken with narrow to wide field-of-view lenses demonstrate the applicability of the proposed solvers.
We report the formation of self-assembled monolayers of a molecular photoswitch (azobenzene-bithiophene derivative, AzBT) on cobalt via a thiol covalent bond. We study the electrical properties of the molecular junctions formed with the tip of a conductive atomic force microscope under ultra-high vacuum. The statistical analysis of the current-voltage curves shows two distinct states of the molecule conductance, suggesting the coexistence of both the trans and cis azobenzene isomers on the surface. The cis isomer population (trans isomer) increases (decreases) upon UV light irradiation. The situation is reversed under blue light irradiation. The experiments are confronted to first-principle calculations performed on the molecular junctions with the Non-Equilibrium Green's Function formalism combined with Density Functional Theory (NEGF/DFT). The theoretical results consider two different molecular orientations for each isomer. Whereas the orientation does not affect the conductance of the trans isomer, it significantly modulates the conductance of the cis isomer and the resulting conductance ON/OFF ratio of the molecular junction. This helps identifying the molecular orientation at the origin of the observed current differences between the trans and cis forms. The ON state is associated to the trans isomer irrespective of its orientation in the junction, while the OFF state is identified as a cis isomer with its azobenzene moiety folded upward with respect to the bithiophene core. The experimental and calculated ON/OFF conductance ratios have a similar order of magnitude. This conductance ratio seems reasonable to make these Co-AzBT molecular junctions a good test-bed to further explore the relationship between the spin-polarized charge transport, the molecule conformation and the molecule-Co spinterface.
We argue that a necessary condition for hypoellipticity is that the polar is not a spiral domain.
We analyze divergencies in 2-point and 3-point functions for noncommutative $\theta$-expanded SU(2)-gauge theory with massless fermions. We show that, after field redefinition and renormalization of couplings, one divergent term remains.
The conversion factor $\alpha_{\rm CO}$ from the observable CO(1-0) luminosity to the mass of molecular gas is known to vary between isolated galaxies and some mergers, but the underlying reasons are not clearly understood. Thus, the value(s) of $\alpha_{\rm CO}$ to be adopted remain highly uncertain. To provide better constraints, we apply the large velocity gradient method to a series of hydrodynamical simulations of galaxies and derive the evolution of $\alpha_{\rm CO}$. We report significant variations of $\alpha_{\rm CO}$, and identify three distinct regimes: disk galaxies, starbursts and post-burst phases. We show that estimating the star formation rate over 20 Myr smooths out some of these differences, but still maintains a distinction between disks and starbursts. We find a tighter correlation of $\alpha_{\rm CO}$ with the gas depletion time than with star formation rate, yet with deviations induced by the transitions to and from the starburst episodes. We conclude that $\alpha_{\rm CO}$ fluctuates because of both the feedback energy and the velocity dispersion. Identifying the phase of an interaction by classical means (e.g. morphology, luminosity) could then help selecting the relevant conversion factor to be used and get more accurate estimates of the molecular masses of galaxies.
We examine the relationship between Type Ia Supernova (SN Ia) Hubble residuals and the properties of their host galaxies using a sample of 115 SNe Ia from the Nearby Supernova Factory (SNfactory). We use host galaxy stellar masses and specific star-formation rates fitted from photometry for all hosts, as well as gas-phase metallicities for a subset of 69 star-forming (non-AGN) hosts, to show that the SN Ia Hubble residuals correlate with each of these host properties. With these data we find new evidence for a correlation between SN Ia intrinsic color and host metallicity. When we combine our data with those of other published SN Ia surveys, we find the difference between mean SN Ia brightnesses in low and high mass hosts is 0.077 +- 0.014 mag. When viewed in narrow (0.2 dex) bins of host stellar mass, the data reveal apparent plateaus of Hubble residuals at high and low host masses with a rapid transition over a short mass range (9.8 <= log(M_*/M_Sun) <= 10.4). Although metallicity has been a favored interpretation for the origin of the Hubble residual trend with host mass, we illustrate how dust in star-forming galaxies and mean SN Ia progenitor age both evolve along the galaxy mass sequence, thereby presenting equally viable explanations for some or all of the observed SN Ia host bias.
Every set $A$ of positive integers with upper Banach density 1 contains an infinite sequence of pairwise disjoint subsets $(B_i)_{i=1}^{\infty}$ such that $B_i$ has upper Banach density 1 for all $i \in \mathbf{N}$ and $\sum_{i\in I} B_i \subseteq A$ for every nonempty finite set $I$ of positive integers.
The microscopic approach quantum dissipation process presented by Yu and Sun [Phys. Rev., A49(1994)592, A51(1995)1845] is developed to analyze the wave function structure of dynamic evolution of a typical dissipative system, a single mode boson soaked in a bath of many bosons. In this paper, the wave function of total system is explicitly obtained as a product of two components of the system and the bath in the coherent state representation. It not only describes the influence of the bath on the variable of the system through the Brownian motion, but also manifests the back- action of the system on the bath and the effects of the mutual interaction among the bosons of the bath. Due to the back-action, the total wave function can only be partially factorizable even for the Brownian motion can be ignored in certain senses, such as the cases with weak coupling and large detuning
The electronic properties of a graphene sheet with attached hydrogen atoms is studied using a modified Falicov-Kimball model on the honeycomb lattice. It is shown that in the ground state this system separates into two phases: fully hydrogenated graphene (graphane) and hydrogen-free graphene. The graphene-graphane boundary acquires a positive interface tension. Therefore, the graphene-graphane interface becomes a straight line, slightly rippled by thermal fluctuations. A smooth interface may be useful for the fabrication of mesoscopic graphene-based devices.
We study elastic proton-nucleus scattering at intermediate energies. The nucleon-nucleus optical potential is derived from the Bonn nucleon-nucleon potential and the Dirac-Brueckner approach for nuclear matter. Our calculations, which do not contain any adjustable parameters, yield good agreement with experiment.
Consequences of explicit symmetry breaking in a physically motivated model of SU(N) antiferromagnet in spatial dimensions one and two are studied. It is shown that the case N=3, which can be realized in spin-1 cold atom systems, displays special properties distinctly different from those for N>=4. Qualitative form of the phase diagram depending on the model parameters is given.
We provide a L\'evy-It\^o decomposition of sample paths of L\'evy processes with values in complete locally convex Suslin spaces. This class of state spaces contains the well investigated examples of separable Banach spaces, as well as Fr\'echet or distribution spaces among many others. Sufficient conditions for the existence of a pathwise compensated Poisson integral handling infinite activity of the L\'evy process are given.
The study of the gamma-ray radiation produced by cosmic rays that escape their accelerators is of paramount importance for (at least) two reasons: first, the detection of those gamma-ray photons can serve to identify the sources of cosmic rays and, second, the characteristics of that radiation give us constraints on the way in which cosmic rays propagate in the interstellar medium. This paper reviews the present status of the field.
In this paper, we introduce a map between the q-deformed gauge fields defined on the GL$_{q}(N) $-covariant quantum hyperplane and the ordinary gauge fields. Perturbative analysis of the q-deformed QED at the classical level is presented and gauge fixing $\grave{a} $ la BRST is discussed. An other star product defined on the hybrid $(q,h) $% -plane is explicitly constructed .
Eruptive activity in the solar corona can often lead to the propagation of shock waves. In the radio domain the primary signature of such shocks are type II radio bursts, observed in dynamic spectra as bands of emission slowly drifting towards lower frequencies over time. These radio bursts can sometimes have inhomogeneous and fragmented fine structure, but the cause of this fine structure is currently unclear. Here we observe a type II radio burst on 2019-March-20th using the New Extension in Nan\c{c}ay Upgrading LOFAR (NenuFAR), a radio interferometer observing between 10-85 MHz. We show that the distribution of size-scales of density perturbations associated with the type II fine structure follows a power law with a spectral index in the range of $\alpha=-1.7$ to -2.0, which closely matches the value of $-5/3$ expected of fully developed turbulence. We determine this turbulence to be upstream of the shock, in background coronal plasma at a heliocentric distance of $\sim$2 R$_{\odot}$. The observed inertial size-scales of the turbulent density inhomogeneities range from $\sim$62 Mm to $\sim$209 km. This shows that type II fine structure and fragmentation can be due to shock propagation through an inhomogeneous and turbulent coronal plasma, and we discuss the implications of this on electron acceleration in the coronal shock.
One of the key challenges for the implementation of scalable quantum information processing is the design of scalable architectures that support coherent interaction and entanglement generation between distant quantum systems. We propose a nanotube double quantum dot spin transducer that allows to achieve steady-state entanglement between nitrogen-vacancy center spins in diamond with spatial separations over micrometers. The distant spin entanglement further enables us to design a scalable architecture for solid-state quantum information processing based on a hybrid platform consisting of nitrogen-vacancy centers and carbon-nanotube double quantum dots.
Results of experimental pump-probe spectroscopy of a quantum dash optical amplifier biased at transparency are presented. Using strong pump pulses we observe a competition between free carrier absorption and two-photon induced stimulated emission that can have drastic effects on the transmission dynamics. Thus, both enhancement as well as suppression of the transmission can be observed even when the amplifier is biased at transparency. A simple theoretical model taking into account two-photon absorption and free carrier absorption is presented that shows good agreement with the measurements.
We present an edge preserving and denoising filter for enhancing the features in images, which contain an ROI having a narrow spatial extent. Typical examples include angiograms, or ROI spatially distributed in multiple locations and contained within an outlying region, such as in multiple-sclerosis. The filtering involves determination of multiplicative weights in the spatial domain using an extended set of neighborhood directions. Equivalently, the filtering operation may be interpreted as a combination of directional filters in the frequency domain, with selective weighting for spatial frequencies contained within each direction. The advantages of the proposed filter in comparison to specialized non-linear filters, which operate on diffusion principle, are illustrated using numerical phantom data. The performance evaluation is carried out on simulated images from BrainWeb database for multiple-sclerosis, acute ischemic stroke using clinically acquired FLAIR images and MR angiograms.
We investigated a set of 54 interplanetary coronal mass ejection (ICME) events whose solar sources are very close to the disk center (within 15 degrees from the central meridian). The ICMEs consisted of 23 magnetic cloud (MC) events and 31 non-MC events. Our analyses suggest that the MC and non-MC ICMEs have more or less the same eruption characteristics at the Sun in terms of soft X-ray flares and CMEs. Both types have significant enhancements in charge states, although the non-MC structures have slightly lower levels of enhancement. The overall duration of charge state enhancement is also considerably smaller than that than that in MCs as derived from solar wind plasma and magnetic signatures. We find very good correlation between the Fe and O charge state measurements and the flare properties such as soft X-ray flare intensity and flare temperature for both MCs and non-MCs. These observations suggest that both MC and non-MC ICMEs are likely to have a flux-rope structure and the unfavorable observational geometry may be responsible for the appearance of non-MC structures at 1 AU. We do not find any evidence for active region expansion resulting in ICMEs lacking a flux rope structure because the mechanism of producing high charge states and the flux rope structure at the Sun is the same for MC and non-MC events.
We show how to optimally discriminate between K distinct quantum states, of which N copies are available, using one-at-a-time interactions with each of the N copies. While this task (famously) requires joint measurements on all N copies, we show that it can be solved with one-at-a-time "coherent measurements" performed by an apparatus with log(K) qubits of quantum memory. We apply the same technique to optimal discrimination between K distinct N-particle matrix product states of bond dimension D, using a coherent measurement apparatus with log(K) + log(D) qubits of memory.
This paper presents a full derivation of the variance-to-mean or Feynman-alpha formula in a two energy group and two spatial region-treatment. The derivation is based on the Chapman - Kolmogorov equation with the inclusion of all possible neutron reactions and passage intensities between the two regions. In addition, the two-group one-region and the two-region one-group Feynman-alpha formulas, treated earlier in the literature for special cases, are extended for further types and positions of detectors.We focus on the possibility of using these theories for accelerator-driven systems and applications in the safeguards domain, such as the differential self-interrogation method and the differential die-away method. This is due to the fact that the predictions from the models which are currently used do not fully describe all the effects in the heavily reflected fast or thermal systems. Therefore, in conclusion a comparative study of the two-group two-region, the two-group one-region, the one-group two-region and the one-group one-region Feynman-alpha models is discussed.
We report here on anisotropy of spin polarization obtained in lateral all-semiconductor all-electrical spin injection devices, employing $p^{+}-$(Ga,Mn)As/$n^{+}-$GaAs Esaki diode structures as spin aligning contacts, resulting from the dependence of the efficiency of spin tunneling on the orientation of spins with respect to different crystallographic directions. We observed an in-plane anisotropy of $~8%$ in case of spins oriented either along $[1\bar{1}0]$ or $[110]$ directions and $~25%$ anisotropy between in-plane and perpendicular-to-plane orientation of spins.
Dark energy has a dramatic effect on the dynamics of the universe, causing the recently discovered acceleration of the expansion. The dynamics are also central to the behavior of the growth of large scale structure, offering the possibility that observations of structure formation provide a sensitive probe of the cosmology and dark energy characteristics. In particular, dark energy with a time varying equation of state can have an influence on structure formation stretching back well into the matter dominated epoch. We analyze this impact, first calculating the linear perturbation results, including those for weak gravitational lensing. These dynamical models possess definite observable differences from constant equation of state models. Then we present a large scale numerical simulation of structure formation, including the largest volume to date involving a time varying equation of state. We find the halo mass function is well described by the Jenkins et al. mass function formula. We also show how to interpret modifications of the Friedmann equation in terms of a time variable equation of state. The results presented here provide steps toward realistic computation of the effect of dark energy in cosmological probes involving large scale structure, such as cluster counts, Sunyaev-Zel'dovich effect, or weak gravitational lensing.
We study dynamical mass measurements of galaxy clusters contaminated by interlopers and show that a modern machine learning (ML) algorithm can predict masses by better than a factor of two compared to a standard scaling relation approach. We create two mock catalogs from Multidark's publicly available $N$-body MDPL1 simulation, one with perfect galaxy cluster membership information and the other where a simple cylindrical cut around the cluster center allows interlopers to contaminate the clusters. In the standard approach, we use a power-law scaling relation to infer cluster mass from galaxy line-of-sight (LOS) velocity dispersion. Assuming perfect membership knowledge, this unrealistic case produces a wide fractional mass error distribution, with a width of $\Delta\epsilon\approx0.87$. Interlopers introduce additional scatter, significantly widening the error distribution further ($\Delta\epsilon\approx2.13$). We employ the support distribution machine (SDM) class of algorithms to learn from distributions of data to predict single values. Applied to distributions of galaxy observables such as LOS velocity and projected distance from the cluster center, SDM yields better than a factor-of-two improvement ($\Delta\epsilon\approx0.67$) for the contaminated case. Remarkably, SDM applied to contaminated clusters is better able to recover masses than even the scaling relation approach applied to uncontaminated clusters. We show that the SDM method more accurately reproduces the cluster mass function, making it a valuable tool for employing cluster observations to evaluate cosmological models.
The standard AGN-galaxy co-evolutionary scenario predicts a phase of deeply buried supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous QSO is revealed ('SB-QSO evolutionary sequence'). The aim of this work is to measure the cold gas reservoir of three highly obscured QSOs to test if their gas fraction is similar to that of sub-millimeter galaxies (SMGs), as expected by some models, and place these measurements in the context of the SB-QSO framework. We target CO(1-0) transition in BzK4892, a Compton Thick (CT) QSO at z=2.6, CO(1-0) in BzK8608 and CO(2-1) in CDF153, two highly obscured QSOs at z=2.5 and z=1.5, respectively. For all these targets, we place 3$\sigma$ upper limits on the CO, with $L'_{CO} < (1.5\div 2.8)\times 10^{10}$ K km/s pc$^2$. We also compare the molecular gas conditions of our targets with those of other systems at z>1, considering normal star forming galaxies and SMGs, unobscured and obscured AGN from the literature. For the AGN samples, we provide an updated and (almost) complete collection of targets with CO follow-up. BzK4892 displays a high star formation efficiency (SFE$=L_{IR}/L'_{CO}>410$ L$_{\odot}$/(K km s$^{-1}$ pc$^2$)) and a gas fraction $f_{gas}<0.1$. Less stringent constraints are derived for the other two targets ($f_{gas}<0.5$ and SFE$>10$). From the comparison with literature data, we found that a) obscured AGN at z>1 are associated with higher SFE and lower $f_{gas}$ with respect to star forming galaxies; b) mildly and highly obscured active galaxies have comparable gas fractions; c) the SFE of CT and obscured AGN are similar to those of unobscured AGN. Within the SB-QSO framework, these findings could be consistent with a scenario where feedback can impact the host galaxy already from the early phases of the SB-QSO sequence.
We report in this paper the numerical simulations of the capture into the 3:1 mean-motion resonance between the planet b and c in the 55 Cancri system. The results show that this resonance can be obtained by a differential planetary migration. The moderate initial eccentricities, relatively slower migration and suitable eccentricity damping rate increase significantly the probability of being trapped in this resonance. Otherwise, the system crosses the 3:1 commensurability avoiding resonance capture, to be eventually captured into a 2:1 resonance or some other higher-order resonances. After the resonance capture, the system could jump from one orbital configuration to another one if the migration continues, making a large region of the configuration space accessible for a resonance system. These investigations help us understand the diversity of resonance configurations and put some constrains on the early dynamical evolution of orbits in the extra-solar planetary systems.