ShantanuT01/DACTYL-Pretraining huggingface dataset:
The front-illuminated (FI) CCDs in the Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory (Chandra) were damaged in the extreme environment of the Earth's radiation belts, causing charge traps that result in enhanced charge transfer inefficiency (CTI) during parallel readout. This causes row-dependent gain, event grade `morphing' (spatial redistribution of charge) and energy resolution degradation.   The ACIS back-illuminated (BI) CCDs also exhibit pronounced CTI due to their manufacturing. It is mild enough that position-dependent energy resolution is not seen, but it is present in both parallel and serial registers. This CTI also changes the gain and event grades, in a spatially complicated way as parallel and serial CTI interact.   Given these realities, we have developed and tuned a phenomenological model of CTI for both FI and BI CCDs and incorporated it into our Monte Carlo simulations of the ACIS CCDs. It models charge loss and the spatial redistribution of charge (trailing), thus reproducing the spatially-dependent gain and grade distribution seen in all ACIS CCDs and the row-dependent energy resolution seen in the FI devices. Here we explore the evidence for CTI, compare our simulations to data, and present a technique for CTI correction based on forward modeling.
We investigate the spectrum of the gauge theory with Chern-Simons term on the noncommutative plane, a modification of the description of the Quantum Hall fluid recently proposed by Susskind. We find a series of the noncommutative massive ``plane wave'' solutions with polarization dependent on the magnitude of the wave-vector. The mass of each branch is fixed by the quantization condition imposed on the coefficient of the noncommutative Chern-Simons term. For the radially symmetric ansatz a vortex-like solution is found and investigated. We derive a nonlinear difference equation describing these solutions and we find their asymptotic form. These excitations should be relevant in describing the Quantum Hall transitions between plateaus and the end transition to the Hall Insulator.
Conversion of microwave radiation into the optical range has been predicted to reach unity quantum efficiency in whispering gallery resonators made from an optically nonlinear crystal and supporting microwave and optical modes simultaneously. In this work we theoretically explore and experimentally demonstrate a resonator geometry that can provide the required phase matching for such a conversion at any desired frequency in the sub-THz range. We show that such a ring-shaped resonator not only allows for the phase matching, but also maximizes the overlap of the interacting fields. As a result, unity-efficient conversion is expected in a resonator with feasible parameters.
The semi-device-independent approach provides a framework for prepare-and-measure quantum protocols using devices whose behavior must not be characterized nor trusted, except for a single assumption on the dimension of the Hilbert space characterizing the quantum carriers. Here, we propose instead to constrain the quantum carriers through a bound on the mean value of a well-chosen observable. This modified assumption is physically better motivated than a dimension bound and closer to the description of actual experiments. In particular, we consider quantum optical schemes where the source emits quantum states described in an infinite-dimensional Fock space and model our assumption as an upper bound on the average photon number in the emitted states. We characterize the set of correlations that may be exhibited in the simplest possible scenario compatible with our new framework, based on two energy-constrained state preparations and a two-outcome measurement. Interestingly, we uncover the existence of quantum correlations exceeding the set of classical correlations that can be produced by devices behaving in a purely pre-determined fashion (possibly including shared randomness). This feature suggests immediate applications to certified randomness generation. Along this line, we analyze the achievable correlations in several prepare-and-measure optical schemes with a mean photon number constraint and demonstrate that they allow for the generation of certified randomness. Our simplest optical scheme works by the on-off keying of an attenuated laser source followed by photocounting. It opens the path to more sophisticated energy-constrained semi-device-independent quantum cryptography protocols, such as quantum key distribution.
Automated text detection is a difficult computer vision task. In order to accurately detect and identity text in an image or video, two major problems must be addressed. The primary problem is implementing a robust and reliable method for distinguishing text vs non-text regions in images and videos. Part of the difficulty stems from the almost unlimited combinations of fonts, lighting conditions, distortions, and other variations that can be found in images and videos. This paper explores key properties of two popular and proven methods for implementing text detection; maximum stable external regions (MSER) and stroke width variation.
We have performed transport spectroscopy on individual ropes of single-walled carbon nanotubes. We find that the levels are Zeeman split in a magnetic field, with a g-factor of 2.04 +- 0.05. The observed pattern of peak splittings indicates the parity of the number of electrons on the dot. In one device there are also signs of the presence of a second dot. We observe features which resemble anticrossings between quantum levels in the two dots, which may be formed from separate conducting nanotubes within the rope.
For a few years now, cosmology has a standard model. By this term, we mean a consistent theoretical background which is at the same time simple and broad enough to offer coherent explanations for the vast majority of cosmological phenomena. This review will briefly summarise the cosmological model, then proceed to discuss what we know from observations about the evolution of the Universe and its contents, and what we conclude about the origin and the future of the Universe and the structures it contains.
An overview of the classical Rankin-Selberg problem involving the asymptotic formula for sums of coefficients of holomorphic cusp forms is given. We also study the function $\Delta(x;\xi) (0\le\xi\le1)$, the error term in the Rankin-Selberg problem weighted by $\xi$-th power of the logarithm. Mean square estimates for $\Delta(x;\xi)$ are proved.
We study 3-jet event topologies in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 13 {\rm\ TeV}$ in a configuration, where one jet is present in the central pseudorapidity region ($|\eta| < 2.0$) while two other jets are in a more forward (same hemisphere) area ($|\eta| > 2.0$). We compare various parton level predictions using: collinear factorisation, $\KT{}$-factorisation with fully off-shell matrix elements and the hybrid framework. We study the influence of different parton distribution functions, initial state radiation, final state radiation, and hadronisation. We focus on differential cross sections as a function of azimuthal angle difference between the leading dijet system and the third jet, which is found to have excellent sensitivity to the physical effects under study.
We exploit more than 1000 star cluster Monte Carlo models from the MOCCA-SURVEY Database I, to infer the local rate density of white dwarf (WD) tidal disruption events (TDEs) in globular clusters (GCs) and young massive clusters (YMCs). We suggest that the WD TDE rate for GCs and YMCs in the local universe is $\sim 90$-$500~{\rm yr}^{-1}~{\rm Gpc}^{-3}$, with 90 % of WD TDEs occurring in GCs. The total WD TDE rate density is $\sim 9$-$50$ times larger than estimated before. Our results show that thermonuclear explosions induced by WD TDEs can be observed at a rate of $\sim 100$-$550~{\rm yr}^{-1}$ by the next generation optical surveys, such as the Legacy Survey of Space & Time by the Vera C. Rubin Observatory. We also find that massive WDs are preferentially disrupted due to mass segregation, and that 20 % of exploding WDs have $\gtrsim 1.0 M_\odot$ despite of the small population of such WDs.
We study the self force acting on a particle endowed with scalar charge, which is held static (with respect to an undragged, static observer at infinity) outside a stationary, axially-symmetric black hole. We find that the acceleration due to the self force is in the same direction as the black hole's spin, and diverges when the particle approaches the outer boundary of the black hole's ergosphere. This acceleration diverges more rapidly approaching the ergosphere's boundary than the particle's acceleration in the absence of the self force. At the leading order this self force is a (post)$^2$-Newtonian effect. For scalar charges with high charge-to-mass ratio, the acceleration due to the self force starts dominating over the regular acceleration already far from the black hole. The self force is proportional to the rate at which the black hole's rotational energy is dissipated. This self force is local (i.e., only the Abraham-Lorentz-Dirac force and the local coupling to Ricci curvature contribute to it). The non-local, tail part of the self force is zero.
Solar active regions, produced by the emergence of tubes of strong magnetic field in the photosphere, are restricted to within 35 degrees of the solar equator. The nature of the dynamo processes that create and renew these fields, and are therefore responsible for solar magnetic phenomena, are not well understood. We analyze the magneto-rotational stability of the solar tachocline for general field geometry. This thin region of strong radial and latitudinal differential rotation, between the radiative and convective zones, is unstable at latitudes above 37 degrees, yet is stable closer to the equator. We propose that small-scale magneto-rotational turbulence prevents coherent magnetic dynamo action in the tachocline except in the vicinity of the equator, thus explaining the latitudinal restriction of active regions. Tying the magnetic dynamo to the tachocline elucidates the physical conditions and processes relevant to solar magnetism.
Here we describe the mission design for SMART-2/LISA Pathfinder. The best trade-off between the requirements of a low-disturbance environment and communications distance is found to be a free-insertion Lissajous orbit around the first co-linear Lagrange point of the Sun-Earth system L1, 1.5x 10^6 km from Earth. In order to transfer SMART-2/LISA Pathfinder from a low Earth orbit, where it will be placed by a small launcher, the spacecraft carries out a number of apogee-raise manoeuvres, which ultimatively place it to a parabolic escape trajectory towards L1. The challenges of the design of a small mission are met, fulfilling the very demanding technology demonstration requirements without creating excessive requirements on the launch system or the ground segment.
We present an extension of work in an earlier paper showing high precision comparisons between black hole perturbation theory and post-Newtonian (PN) theory in their region of overlapping validity for bound, eccentric-orbit, Schwarzschild extreme-mass-ratio inspirals. As before we apply a numerical fitting scheme to extract eccentricity coefficients in the PN expansion of the gravitational wave fluxes, which are then converted to exact analytic form using an integer-relation algorithm. In this work, however, we fit to individual $lmn$ modes to exploit simplifying factorizations that lie therein. Since the previous paper focused solely on the energy flux, here we concentrate initially on analyzing the angular momentum flux to infinity. A first step involves finding convenient forms for hereditary contributions to the flux at low-PN order, analogous to similar terms worked out previously for the energy flux. We then apply the upgraded techniques to find new PN terms through 9PN order and (at many PN orders) to $e^{30}$ in the power series in eccentricity. With the new approach applied to angular momentum fluxes, we return to the energy fluxes at infinity to extend those previous results. Like before, the underlying method uses a \textsc{Mathematica} code based on use of the Mano-Suzuki-Takasugi (MST) function expansion formalism to represent gravitational perturbations and spectral source integration (SSI) to find numerical results at arbitrarily high precision.
Waveguide quantum electrodynamics studies photon-mediated interactions of quantum emitters in a one-dimensional radiation channel. Although signatures of such interactions have been observed previously in a variety of physical systems, observation of coherent cooperative dynamics has been obscured by radiative decay of atoms into the waveguide. Employing transmon qubits as artificial atoms coupled to a microwave coplanar waveguide, here we observe dynamical oscillations in an open system where a designated probe qubit interacts with an entangled dark state of an array of qubits which effectively traps radiation as an atomic cavity. The qubit-cavity system is shown to achieve a large cooperativity of $\mathcal{C}=172$ due to collective enhancement of photon-mediated interactions, entering the strong coupling regime. The quantum coherence of the dark state cavity is also explored through its nonlinear response at the single-excitation level. With realistic refinements, this system is suitable for studying the many-body dynamics of large ($N>10$) quantum spin chains, synthesizing highly non-classical radiation fields on demand, and implementing universal quantum logic operations with high fidelity on information encoded within decoherence-free subspaces.
We present a re-analysis of the ROSAT PSPC data within the central 100 kpc of M87 to search for intrinsic oxygen absorption similar to that recently measured in several galaxies and groups. Using a spatial-spectral deprojection analysis we find the strongest evidence to date for intrinsic oxygen absorption in the hot gas of a galaxy, group, or cluster. Single-phase plasma models modified by intervening Galactic absorption cannot fit the 0.2-2.2 keV PSPC data as they under-predict the 0.2-0.4 keV region and over-predict the 0.5-0.8 keV region where the emission and absorption residuals are obvious upon visual inspection of the spectral fits. Since the excess emission between 0.2-0.4 keV rules out intrinsic absorption from cold gas or dust, the most reasonable model for the excess emission and absorption features is warm, collisionally ionized gas with a temperature of ~10^6 K. Simple multiphase models (cooling flow, two phases) modified by both intervening Galactic absorption and by a single oxygen edge provide good fits and yield temperatures and Fe abundances of the hot gas that agree with previous determinations by ASCA and SAX. The multiphase models of M87 inferred from the PSPC can account for the excess EUV emission observed with EUVE and the excess X-ray absorption inferred from EINSTEIN and ASCA data above 0.5 keV. Although the total mass of the warm gas implied by the oxygen absorption is consistent with the matter deposited by a cooling flow, the suppression of the mass deposition rate and the distortion of the X-ray isophotes in the region where the radio emission is most pronounced suggest some feedback effect from the AGN on the cooling gas. (Abridged)
We have studied the $e^+ e^- \to Z \phi_i \to Z jj$ process, where $\phi_i$ is the Higgs and/or radion bosons. The implications of the radion effects on the preliminary ALEPH data are also discussed. The case of the lighter radion than Higgs boson is disfavored by the ALEPH analyses of the $b$ tagged four-jet data, since the radion predominantly decays into two gluon jets due to the QCD trace anomaly. If the radion is highly degenerate in mass with the Higgs, the cross section can be increased more than at one sigma level, with natural scale of the vacuum expectation value of the radion.
Scaling relations among dark matter (DM) and stellar quantities are a valuable tool to constrain formation scenarios and the evolution of galactic structures. However, most of the DM properties are actually not directly measured, but derived through model dependent mass mapping procedures. It is therefore crucial to adopt theoretically and observationally well founded models. We use here an updated version of the secondary infall model (SIM) to predict the halo density profile, taking into account the effects of angular momentum, dissipative friction and baryons collapse. The resulting family of halo profiles depends on one parameter only, the virial mass, and nicely fits the projected mass and aperture velocity dispersion of a sample of intermediate redshift lens galaxies. We derive DM related quantities (namely the column density and the Newtonian acceleration) and investigate their correlations with stellar mass, luminosity, effective radius and virial mass.
We study the quark helicity distributions at large x in perturbative QCD, taking into account contributions from the valence Fock states of the nucleon which have nonzero orbital angular momentum. These states are necessary to have a nonzero anomalous magnetic moment. We find that the quark orbital angular momentum contributes a large logarithm to the negative helicity quark distributions in addition to its power behavior, scaling as (1-x)^5\log^2(1-x) in the limit of x\to 1. Our analysis shows that the ratio of the polarized over unpolarized down quark distributions, \Delta d/d, will still approach 1 in this limit. By comparing with the experimental data, we find that this ratio should cross zero at x\approx 0.75.
We study theoretically the nonstationary circuit QED system in which the artificial atom transition frequency, or the atom-cavity coupling, have a small periodic time modulation, prescribed externally. The system formed by the atom coupled to a single cavity mode is described by the Rabi Hamiltonian. We show that, in the dispersive regime, when the modulation periodicity is tuned to the `resonances', the system dynamics presents the dynamical Casimir effect, resonant Jaynes-Cummings or resonant Anti-Jaynes-Cummings behaviors, and it can be described by the corresponding effective Hamiltonians. In the resonant atom-cavity regime and under the resonant modulation, the dynamics is similar to the one occurring for a stationary two-level atom in a vibrating cavity, and an entangled state with two photons can be created from vacuum. Moreover, we consider the situation in which the atom-cavity coupling, the atomic frequency, or both have a small nonperiodic time modulation, and show that photons can be created from vacuum in the dispersive regime. Therefore, an analog of the dynamical Casimir effect can be simulated in circuit QED, and several photons, as well as entangled states, can be generated from vacuum due to the anti-rotating term in the Rabi Hamiltonian.
In this thesis I present measurements of the physical properties of the nuclei of Jupiter Family comets (JFCs), based on time-series observations. From the time-series photometry rotation rates and elongations were measured, and from these constraints were placed on the bulk density and porosity of nuclei. Multi-filter imaging was performed to enable measurement of their surface colours. In addition, a large amount of `snap-shot' imaging was performed during the observing runs, and taken with the time-series data is used to measure nuclei sizes. These results are compared with other data from the literature to study the general properties of JFC nuclei.   (Abridged)
This work presents an approach to express the second moment of the completion time with a preempt-repeat model job processed on a machine subject to stochastic breakdowns by some distribution characters of the uptime, downtime and processing time.
The optical emission of InGaN quantum dots embedded in GaN nanowires is dynamically controlled by a surface acoustic wave (SAW). The emission energy of both the exciton and biexciton lines is modulated over a 1.5 meV range at ~330 MHz. A small but systematic difference in the exciton and biexciton spectral modulation reveals a linear change of the biexciton binding energy with the SAW amplitude. The present results are relevant for the dynamic control of individual single photon emitters based on nitride semiconductors.
We provide a formula for the number of $\mathbb{F}_{p}$-points on the Dwork hypersurface $$x_1^n + x_2^n \dots + x_n^n - n \lambda \, x_1 x_2 \dots x_n=0$$ in terms of a $p$-adic hypergeometric function previously defined by the author. This formula holds in the general case, i.e for any $n, \lambda \in \mathbb{F}_p^{*}$ and for all odd primes $p$, thus extending results of Goodson and Barman et al which hold in certain special cases.
We formulate supersymmetric low energy dynamics for BPS dyons in strongly-coupled N=2 Seiberg-Witten theories, and derive wall-crossing formulae thereof. For BPS states made up of a heavy core state and n probe (halo) dyons around it, we derive a reliable supersymmetric moduli dynamics with 3n bosonic coordinates and 4n fermionic superpartners. Attractive interactions are captured via a set of supersymmetric potential terms, whose detail depends only on the charges and the special Kaehler data of the underlying N=2 theories. The small parameters that control the approximation are not electric couplings but the mass ratio between the core and the probe, as well as the distance to the marginal stability wall where the central charges of the probe and of the core align. Quantizing the dynamics, we construct BPS bound states and derive the primitive and the semi-primitive wall-crossing formulae from the first principle. We speculate on applications to line operators and Darboux coordinates, and also about extension to supergravity setting.
We present 3-D MHD and synthetic numerical simulations to follow the evolution of randomly magnetized intra-cluster medium plasma under the effects of powerful, light, hypersonic and bipolar jets. We prescribe the cluster magnetic field (CMF) as a Gaussian random field with power law energy spectrum tuned to the expectation for Kolmogorov turbulence. We investigate the power of jets and the viewing angle used for the synthetic Rotation Measure (RM) observations. We find the model radio sources introduce and amplify fluctuations on the RM statistical properties; the average RM and the RM standard deviation are increased by the action of the jets. This may lead to overestimations of the CMFs' strength up to 70%. The effect correlates with the jet power. Jets distort and amplify CMFs especially near the edges of the lobes and the jets' heads. Thus the RM structure functions are flattened at scales comparable to the source size. Jet-produced RM enhancements depend on the orientation of the jet axis to the line of sight and are thus more apparent in quasars than in radio galaxies.
Charge asymmetry in electron (positron) scattering arises from the interference of the Born amplitude and the box-type amplitude corresponding to two virtual photons exchange. It can be extracted from electron proton and positron proton scattering experiments, in the same kinematical conditions. Considering the virtual photon Compton scattering tensor, which contributes to the box-type amplitude, we separate proton and inelastic contributions in the intermediate state and parametrize the proton form-factors as the sum of a pure QED term and a strong interaction term. Arguments based on analyticity are given in favor of cancellation of contributions from proton strong interaction form factors and of inelastic intermediate states in the box type amplitudes. In frame of this model, with a realistic expression for nucleon form-factors, numerical estimations are given for moderately high energies.