ShantanuT01/DACTYL-Pretraining huggingface dataset:
As the dimensions of a conductor approach the nano-scale, quantum effects will begin to dominate its behavior. This entails the exciting possibility of controlling the conductance of a device by direct manipulation of the electron wave function. Such control has been most clearly demonstrated in mesoscopic semiconductor structures at low temperatures. Indeed, the Aharanov-Bohm effect, conductance quantization and universal conductance fluctuations are direct manifestations of the electron wave nature. However, an extension of this concept to more practical emperatures has not been achieved so far. As molecules are nano-scale objects with typical energy level spacings (~eV) much larger than the thermal energy at 300 K (~25 meV), they are natural candidates to enable such a break-through. Fascinating phenomena including giant magnetoresistance, Kondo effects and conductance switching, have previously been demonstrated at the molecular level. Here, we report direct evidence for destructive quantum interference in charge transport through two-terminal molecular junctions at room temperature. Furthermore, we show that the degree of interference can be controlled by simple chemical modifications of the molecule. Not only does this provide the experimental demonstration of a new phenomenon in quantum charge transport, it also opens the road for a new type of molecular devices based on chemical or electrostatic control of quantum interference.
The plastic component of the deformation gradient plays a central role in finite kinematic models of plasticity. However, its characterization has been the source of extended debates in the literature and many important issues still remain unresolved. Some examples are the micromechanical understanding of F=FeFp with multiple active slip systems, the uniqueness of the decomposition, or the characterization of the plastic deformation without reference to the so-called intermediate configuration. In this paper, we shed some light to these issues via a two-dimensional kinematic analysis of the plastic deformation induced by discrete slip surfaces and the corresponding dislocation structures. In particular, we supply definitions for the elastic and plastic components of the deformation gradient as a function of the active slip systems without any a priori assumption on the decomposition of the total deformation gradient. These definitions are explicitly and uniquely given from the microstructure and do not make use of any unrealizable intermediate configuration. These quantities are then passed to the continuous limit via homogenization, i.e., by increasing the number of slip surfaces to infinity and reducing the lattice parameter to zero. This continuum limit is computed for several illustrative examples, where the well-known multiplicative decomposition of the total deformation gradient is recovered. Additionally, by similar arguments, an expression of the dislocation density tensor is obtained as the limit of discrete dislocation densities.
We analyze the stress-energy tensor necessary to generate a general stationary and axisymmetric spacetime. The constraints on the geometry arising from considering a perfect fluid as a source are derived. For a fluid with a nonzero stress tensor, we obtain two necessary conditions on the metric. As an example, we show that the rotating wormhole presented in the literature can not be described by either a perfect fluid or by a fluid with anisotropic stresses.
We present atomistic simulations of the D0 to D- charging energies of a gated donor in silicon as a function of applied fields and donor depths and find good agreement with experimental measure- ments. A self-consistent field large-scale tight-binding method is used to compute the D- binding energies with a domain of over 1.4 million atoms, taking into account the full bandstructure of the host, applied fields, and interfaces. An applied field pulls the loosely bound D- electron towards the interface and reduces the charging energy significantly below the bulk values. This enables formation of bound excited D-states in these gated donors, in contrast to bulk donors. A detailed quantitative comparison of the charging energies with transport spectroscopy measurements with multiple samples of arsenic donors in ultra-scaled FinFETs validates the model results and provides physical insights. We also report measured D-data showing for the first time the presence of bound D-excited states under applied fields.
We introduce a general class of models for charaterizing the non-Gaussian properties of foreground contaminants in the cosmic microwave background with view towards the removal of the non-primordial non-Gaussian signal from the primordial one. This is important not only for treating temperature maps but also for characterizing the nature and origin of the primordial cosmological perturbations and thus establishing a theory of the early universe.
Motivated by recent experiments, we append long ranged Coulomb interactions to dominant strong local correlations and study the resulting $t$-$J$-$V_C$ model for the 2-dimensional cuprate materials. This model includes the effect of short ranged Hubbard-Gutzwiller-Kanamori type correlations and long ranged Coulomb interactions on tight binding electrons. We calculate the $ \{\vec{q},\omega\}$ dependent charge density fluctuations in this model using the extremely correlated fermi liquid theory, characterized by quasiparticles with very small weight $Z$. We develop a novel set of formulae to represent the dynamical charge susceptibility and the dielectric function, using a version of the charge-current continuity equation for a band system valid for arbitrary $\vec{q}$. Combining these ingredients, we present results for the dynamical charge susceptibility $\widetilde{\chi}_{\rho\rho}(\vec{q},\omega)$, (longitudinal) dielectric function $\varepsilon(\vec{q},\omega)$, current susceptibility $\widetilde{\chi}_{J J}(\vec{q},\omega)$, conductivity $\sigma(\vec{q},\omega)$, and the plasma frequency for any $\vec{q}$. We also present calculations for the first moment of the structure function and discuss a characteristic energy scale $\Omega_p(\vec{q})$, which locates a peak in $\Im m \, \widetilde{\chi}_{\rho\rho}(\vec{q},\omega)$.
With this Paper we complete a comprehensive study of substructure in dark matter haloes. In Paper I we derived the radial distribution and mass function (MF) of accreted subhaloes (scaled to the radius and mass of the host halo) and showed they are essentially universal. This is not the case, however, for those of stripped subhaloes, which depend on halo mass and assembly history. In Paper II we derived these latter properties in the simplest case of purely accreting haloes. Here we extend the study to ordinary haloes having suffered major mergers. After showing that all the properties of substructure are encoded in the mean truncated-to-original subhalo mass ratio profile, we demonstrate that the dependence of the subhalo MF on halo mass arises from their mass-dependent concentration, while the shape of the subhalo radial distribution depends on the time of the last major merger of the host halo. In this sense, the latter property is a better probe of halo formation time than the former. Unfortunately, this is not the case for the radial distribution of satellites as this profile is essentially disconnected from subhalo stripping and the properties of accreted subhaloes are independent of the halo formation time.
The variation of the mass-to-light ratios M/L of early type galaxies as function of their luminosities L is investigated. It is shown that the tilt beta=0.27 (in the B--band) of the fundamental plane relation M/L ~ L^{beta} can be understood as a combination of two effects: about one-quarter (i.e. dbeta =0.07) is a result of systematic variations of the stellar population properties with increasing luminosity. The remaining three-quarters (i.e. dbeta =0.2) can be completely attributed to nonhomology effects that lead to a systematic change of the surface brightness profiles with increasing luminosity. Consequently, the observed tilt in the K-band (beta=0.17) where stellar population effects are negligible, is explained by nonhomology effects alone. After correcting for nonhomology, the mean value of the mass-to-light ratio of elliptical galaxies (M/L_B) is 7.1+-2.8 (1 sigma scatter).
We characterize the bipartite graphs that minimize the (first-degree based) entropy, among all bipartite graphs of given size, or given size and (upper bound on the) order. The extremal graphs turn out to be complete bipartite graphs, or nearly complete bipartite. Here we make use of an equivalent representation of bipartite graphs by means of Young tableaux, which make it easier to compare the entropy of related graphs. We conclude that the general characterization of the extremal graphs is a difficult problem, due to its connections with number theory, but they are easy to find for specific values of the order $n$ and size $m$. We also give a direct argument to characterize the graphs maximizing the entropy given order and size. We indicate that some of our ideas extend to other degree-based topological indices as well.
We present the results of our search for low- and intermediate mass evolved stars in the outer Galaxy using AllWISE catalogue photometry. We show that the [3.4]-[12] versus [4.6]-[22] colour-colour diagram is most suitable for separating C-rich/O-rich AGB and post- AGB star candidates. We are able to select 2,510 AGB and 24,821 post-AGB star candidates. However, the latter are severely mixed with the known young stellar objects in this diagram.
This paper considers the stability problem of a linear time invariant system in feedback with a string equation. A new Lyapunov functional candidate is proposed based on the use of augmented states which enriches and encompasses the classical Lyapunov functional proposed in the literature. It results in tractable stability conditions expressed in terms of linear matrix inequalities. This methodology follows from the application of the Bessel inequality together with Legendre polynomials. Numerical examples illustrate the potential of our approach through three scenari: a stable ODE perturbed by the PDE, an unstable open-loop ODE stabilized by the PDE and an unstable closed-loop ODE stabilized by the PDE.
Chinese keyword spotting is a challenging task as there is no visual blank for Chinese words. Different from English words which are split naturally by visual blanks, Chinese words are generally split only by semantic information. In this paper, we propose a new Chinese keyword spotter for natural images, which is inspired by Mask R-CNN. We propose to predict the keyword masks guided by text line detection. Firstly, proposals of text lines are generated by Faster R-CNN;Then, text line masks and keyword masks are predicted by segmentation in the proposals. In this way, the text lines and keywords are predicted in parallel. We create two Chinese keyword datasets based on RCTW-17 and ICPR MTWI2018 to verify the effectiveness of our method.
We investigate the prospects of measuring the cosmic magnification effect by cross-correlating neutral hydrogen intensity mapping (HI IM) maps with background optical galaxies. We forecast the signal-to-noise ratio for HI IM data from SKA1-MID and HIRAX, combined with LSST photometric galaxy samples. We find that, thanks to their different resolutions, SKA1-MID and HIRAX are highly complementary in such an analysis. We predict that SKA1-MID can achieve a detection with a signal-to-noise ratio of $\sim 15$ on a multipole range of $\ell \lesssim 200$, while HIRAX can reach a signal-to-noise ratio of $\sim 50$ on $200 < \ell < 2000$. We conclude that measurements of the cosmic magnification signal will be possible on a wide redshift range with foreground HI intensity maps up to $z \lesssim 2$, while optimal results are obtained when $0.6 \lesssim z \lesssim 1.3$. Finally, we perform a signal to noise analysis that shows how these measurements can constrain the HI parameters across a wide redshift range.
A new class of deformation of the matrix model of M-theory is considered. The deformation is analogous to the so-called $\b$-deformation of $D=3+1$, $\mN=4$ Super Yang-Mills theory, which preserves the conformal symmetry. It is shown that the deformed matrix model can be considered as a matrix model of M-theory on a certain curved background in eleven-dimensional supergravity, under a scaling limit involving the deformation parameter and $N$ (the size of the matrices). The background belongs to the so-called pp-wave type metric with a non-constant four-form flux depending linearly on transverse coordinates. Some stable solutions of the deformed model are studied, which correspond to membranes with the torus topology. In particular, it is found that apparently distinct configurations of membranes, having different winding numbers, are indistinguishable in the matrix model. Simultaneous introduction of both $\b$-deformation and mass-deformation is also considered, and, in particular, a situation is found in which the stable membrane configuration interpolates between a torus and a sphere, depending on the values of the deformation parameters.
The dispersion relations in the real and imaginary parts of the meson self-energies are studied to check the consistency of the "renormalization" in cutoff field theory. It is shown that the dispersion relations are preserved by the "renormalization"even if the finite cutoff and regulator are introduced in the calculation by hand.
The Sommerfeld rescattering formula is compared to the e+e- -> ppbar BaBar data at threshold and above. While there is the expected Coulomb enhancement at threshold, two unexpected outcomes have been found: |G^p (4M_p^2)|= 1, like for a pointlike fermion, and moreover data show that the resummation factor in the Sommerfeld formula is not needed. Other e+e- -> baryon-antibaryon cross sections show a similar behavior near threshold.
A complete geometric unification of gravity and electromagnetism is proposed by considering two aspects of torsion: its relation to spin established in Einstein--Cartan theory and the possible interpretation of the torsion trace as the electromagnetic potential. Starting with a Lagrangian built of Dirac spinors, orthonormal tetrads, and a complex rather than a real linear connection we define an extended spinor derivative by which we obtain not only a very natural unification, but can also fully clarify the nontrivial underlying fibre bundle structure. Thereby a new type of contact interaction between spinors emerges, which differs from the usual one in Einstein--Cartan theory. The splitting of the linear connection into a metric and an electromagnetic part together with a characteristic length scale in the theory strongly suggest that gravity and electromagnetism have the same geometrical origin.
Materials with strong spin-orbit interactions are presently a main target in the search for systems with novel magnetic properties. Magnetic anisotropies can be very large in such compounds, ranging from strongly frustrated Kitaev exchange in honeycomb iridates and the associated spin-liquid states to robust antisymmetric couplings in square-lattice Sr_2IrO_4 . Here we predict from ab initio quantum chemistry calculations that another highly unusual regime is realized in pyrochlore iridium oxides: the nearest-neighbor Heisenberg interaction can vanish whilst the antisymmetric Dzyaloshinskii- Moriya exchange reaches values as large as 5 meV, a result which challenges common notions and existing phenomenological models of magnetic superexchange. The resulting spin excitation spectra reveal a very flat magnon dispersion in the Nd- and Tb-based pyrochlore iridates, suggesting the possibility of using these modes to store magnetic information. Indeed the magnetization dynamics indicates that these modes are unable to propagate out of the excitation region.
We study the decay of the lightest neutral Higgs boson to a charm quark pair at full one-loop level in the MSSM with non-minimal quark flavour violation (QFV). In the numerical analysis we consider mixing between the second and the third squark generation and all relevant constraints from B meson data are taken into account. It is shown that the full one-loop corrected decay width can be quite sensitive to the MSSM QFV parameters due to large $\tilde c - \tilde t$ mixing and large trilinear couplings. After summarising the theoretical and experimental errors, we conclude that an observation of these SUSY QFV effects is possible at the ILC.
The strong and electromagnetic properties of the Lambda(1405) hyperon are studied in the framework of the bound state soliton model. We explicitly evaluate the strong coupling constant g(Lambda^*-N-K), the Lambda^* magnetic moment, mean square radii and radiative decay amplitudes. The results are shown to be in general agreement with available empirical data. A comparison with results of other models is also presented.
We have observed propagation of Edge Magneto-Plasmon (EMP) modes in graphene in the Quantum Hall regime by performing picosecond time of flight measurements between narrow contacts on the perimeter of micrometric exfoliated graphene. We find the propagation to be chiral with low attenuation and to have a velocity which is quantized on Hall plateaus. The velocity has two contributions, one arising from the Hall conductivity and the other from carrier drift along the edge, which we were able to separate by their different filling factor dependence. The drift component is found to be slightly less than the Fermi velocity as expected for graphene dynamics in an abrupt edge potential. The Hall conduction contribution is slower than expected and indicates a characteristic length in the Coulomb potential from the Hall charge of about 500 nm. The experiment illustrates how EMP can be coupled to the electromagnetic field, opening the perspective of GHz to THz chiral plasmonics applications to devices such as voltage controlled phase shifters, circulators, switches and compact, tunable ring resonators.
A Diophantine figure is a set of points on the integer grid $\mathbb{Z}^{2}$ where all mutual Euclidean distances are integers. We also speak of Diophantine graphs. In this language a Diophantine figure is a complete Diophantine graph. Due to a famous theorem of Erd\H{o}s and Anning there are complete Diophantine graphs which are not contained in larger ones. We call them Erd\H{o}s-Diophantine graphs. A special class of Diophantine graphs are Diophantine carpets. These are planar triangulations of a subset of the integer grid.   We give an effective construction for Erd\H{o}s-Diophantine graphs and characterize the chromatic number of Diophantine carpets.
Continuous state branching processes with immigration are studied. We are particularly concerned with the associated (non-symmetric) Dirichlet form. After observing that gamma distributions are only reversible distributions for this class of models, we prove that every generalized gamma convolution is a stationary distribution of the process with suitably chosen branching mechanism and with continuous immigration. For such non-reversible processes, the strong sector condition is discussed in terms of a characteristic called the Thorin measure. In addition, some connections with notion from noncommutative probability theory will be pointed out through calculations involving the Stieltjes transform.
Generative Adversarial Networks (GANs) have made a dramatic leap in high-fidelity image synthesis and stylized face generation. Recently, a layer-swapping mechanism has been developed to improve the stylization performance. However, this method is incapable of fitting arbitrary styles in a single model and requires hundreds of style-consistent training images for each style. To address the above issues, we propose BlendGAN for arbitrary stylized face generation by leveraging a flexible blending strategy and a generic artistic dataset. Specifically, we first train a self-supervised style encoder on the generic artistic dataset to extract the representations of arbitrary styles. In addition, a weighted blending module (WBM) is proposed to blend face and style representations implicitly and control the arbitrary stylization effect. By doing so, BlendGAN can gracefully fit arbitrary styles in a unified model while avoiding case-by-case preparation of style-consistent training images. To this end, we also present a novel large-scale artistic face dataset AAHQ. Extensive experiments demonstrate that BlendGAN outperforms state-of-the-art methods in terms of visual quality and style diversity for both latent-guided and reference-guided stylized face synthesis.
Classical electron theory with classical electromagnetic zero-point radiation (stochastic electrodynamics) is the classical theory which most closely approximates quantum electrodynamics. Indeed, in inertial frames, there is a general connection between classical field theories with classical zero-point radiation and quantum field theories. However, this connection does not extend to noninertial frames where the time parameter is not a geodesic coordinate. Quantum field theory applies the canonical quantization procedure (depending on the local time coordinate) to a mirror-walled box, and, in general, each non-inertial coordinate frame has its own vacuum state. In complete contrast, the spectrum of random classical zero-point radiation is based upon symmetry principles of relativistic spacetime; in empty space, the correlation functions depend upon only the geodesic separations (and their coordinate derivatives) between the spacetime points. It makes no difference whether a box of classical zero-point radiation is gradually or suddenly set into uniform acceleration; the radiation in the interior retains the same correlation function except for small end-point (Casimir) corrections. Thus in classical theory where zero-point radiation is defined in terms of geodesic separations, there is nothing physically comparable to the quantum distinction between the Minkowski and Rindler vacuum states. It is also noted that relativistic classical systems with internal potential energy must be spatially extended and can not be point systems. Based upon the classical analysis, it is suggested that the claimed heating effects of acceleration through the vacuum may not exist in nature.
The paper is devoted to further development of the new approach in equilibrium statistical mechanics the basis of which was worked out in a series of articles by the author. The approach proceeds on the use of a hierarchy of equations for reduced density matrices in the case of thermodynamic equilibrium. The present paper deals with a system containing particles of several kinds with arbitrary spin, for which the hierarchy obtained previously for a single-component system is generalized. Thermodynamics of the multicomponent system described by the hierarchy deduced is constructed as well.
In this paper, we consider certain finite sums related to the "largest odd divisor", and we obtain, using simple ideas and recurrence relations, sharp upper and lower bounds for these sums.
Motivated by the definition of super-Teichm\"uller spaces, and Penner-Zeitlin's recent extension of this definition to decorated super-Teichm\"uller space, as examples of super Riemann surfaces, we use the super Ptolemy relations to obtain formulas for super $\lambda$-lengths associated to arcs in a bordered surface. In the special case of a disk, we are able to give combinatorial expansion formulas for the super $\lambda$-lengths associated to diagonals of a polygon in the spirit of Ralf Schiffler's $T$-path formulas for type $A$ cluster algebras. We further connect our formulas to the super-friezes of Morier-Genoud, Ovsienko, and Tabachnikov, and obtain partial progress towards defining super cluster algebras of type $A_n$. In particular, following Penner-Zeitlin, we are able to get formulas (up to signs) for the $\mu$-invariants associated to triangles in a triangulated polygon, and explain how these provide a step towards understanding odd variables of a super cluster algebra.