ShantanuT01/DACTYL-Pretraining huggingface dataset:
Quantum phenomena are relevant to the transport of light atoms and molecules through nanoporous two-dimensional (2D) membranes. Indeed, confinement provided by (sub-)nanometer pores enhances quantum effects such as tunneling and zero point energy (ZPE), even leading to quantum sieving of different isotopes of a given element. However, these features are not always taken into account in approaches where classical theories or approximate quantum models are preferred. In this work we present an exact three-dimensional wave packet propagation treatment for simulating the passage of atoms through periodic 2D membranes. Calculations are reported for the transmission of $^3$He and $^4$He through graphdiyne as well as through a holey graphene model. For He-graphdiyne, estimations based on tunneling-corrected transition state theory are correct: both tunneling and ZPE effects are very important but competition between each other leads to a moderately small $^4$He/$^3$He selectivity. Thus, formulations that neglect one or another quantum effect are inappropriate. For the transport of He isotopes through leaky graphene, the computed transmission probabilities are highly structured suggesting widespread selective adsorption resonances and the resulting rate coefficients and selectivity ratios are not in agreement with predictions from transition state theory. Present approach serves as a benchmark for studies of the range of validity of more approximate methods.
In the present paper, we deal with a new continuous and compact embedding theorems for the fractional Orlicz-Sobolev spaces, also, we study the existence of infinitely many nontrivial solutions for a class of non-local fractional Orlicz-Sobolev Schr\"{o}dinger equations whose simplest prototype is $$(-\triangle)^{s}_{m}u+V(x)m(u)=f(x,u),\ x\in\mathbb{R}^{d},$$ where $0<s<1$, $d\geq2$ and $(-\triangle)^{s}_{m}$ is the fractional $M$-Laplace operator. The proof is based on the variant Fountain theorem established by Zou.
The challenge of parasitic bulk doping in Bi-based 3D topological insulator materials is still omnipresent, especially when preparing samples by molecular beam epitaxy (MBE). Here, we present a heterostructure approach for epitaxial BSTS growth. A thin n-type Bi$_2$Se$_3$ (BS) layer is used as an epitaxial and electrostatic seed which drastically improves the crystalline and electronic quality and reproducibility of the sample properties. In heterostructures of BS with p-type (Bi$_{1-x}$Sb$_x$)$_2$(Te$_{1-y}$Se$_y$)$_3$ (BSTS) we demonstrate intrinsic band bending effects to tune the electronic properties solely by adjusting the thickness of the respective layer. The analysis of weak anti-localization features in the magnetoconductance indicates a separation of top and bottom conduction layers with increasing BSTS thickness. By temperature- and gate-dependent transport measurements, we show that the thin BS seed layer can be completely depleted within the heterostructure and demonstrate electrostatic tuning of the bands via a back-gate throughout the whole sample thickness.
Quantum walks are the quantum mechanical analogue of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8x8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high fidelity single and two particle quantum walks. Furthermore, with the high programmability of the quantum processor, we implemented a Mach-Zehnder interferometer where the quantum walker coherently traverses in two paths before interfering and exiting. By tuning the disorders on the evolution paths, we observed interference fringes with single and double walkers. Our work is an essential milestone in the field, brings future larger scale quantum applications closer to realization on these noisy intermediate-scale quantum processors.
We show that, contrary to recent criticism, our previous work yields a reasonable class of solutions for the massless scalar field in the presence of signature change.
The integration of the spin degree of freedom in charge-based electronic devices has revolutionised both sensing and memory capability in microelectronics. Further development in spintronic devices requires electrical manipulation of spin current for logic operations. The approach followed so far, inspired by the seminal proposal of the Datta and Das spin modulator, has relied on the spin-orbit field as a medium for electrical control of the spin state. However, the still standing challenge is to find a material whose spin-orbit-coupling (SOC) is weak enough to transport spins over long distances, while also being strong enough to allow their electrical manipulation. Here we demonstrate a radically different approach by engineering a heterostructure from atomically thin crystals, which are "glued" by weak van der Waals (vdW) forces and which combine the superior spin transport properties of graphene with the strong SOC of the semiconducting MoS$_{2}$. The spin transport in the graphene channel is modulated between ON and OFF states by tuning the spin absorption into the MoS$_{2}$ layer with a gate electrode. Our demonstration of a spin field-effect transistor using two-dimensional (2D) materials identifies a new route towards spin logic operations for beyond CMOS technology.
Contrastive learning is a key technique of modern self-supervised learning. The broader accessibility of earlier approaches is hindered by the need of heavy computational resources (e.g., at least 8 GPUs or 32 TPU cores), which accommodate for large-scale negative samples or momentum. The more recent SimSiam approach addresses such key limitations via stop-gradient without momentum encoders. In medical image analysis, multiple instances can be achieved from the same patient or tissue. Inspired by these advances, we propose a simple triplet representation learning (SimTriplet) approach on pathological images. The contribution of the paper is three-fold: (1) The proposed SimTriplet method takes advantage of the multi-view nature of medical images beyond self-augmentation; (2) The method maximizes both intra-sample and inter-sample similarities via triplets from positive pairs, without using negative samples; and (3) The recent mix precision training is employed to advance the training by only using a single GPU with 16GB memory. By learning from 79,000 unlabeled pathological patch images, SimTriplet achieved 10.58% better performance compared with supervised learning. It also achieved 2.13% better performance compared with SimSiam. Our proposed SimTriplet can achieve decent performance using only 1% labeled data. The code and data are available at https://github.com/hrlblab/SimTriple.
One of the outstanding questions in astronomy today is how gas flows from the circumgalactic medium (CGM) onto the disks of galaxies and then transitions from the diffuse atomic medium into molecular star-forming cores. For studies of the CGM, the Next Generation Very Large Array (ngVLA) will have the sensitivity and resolution to measure the sizes of the neutral atomic hydrogen (HI) disks of galaxies and complete a census of the HI content around galaxies. Within galaxies, the ngVLA will be able to resolve HI clouds in large numbers of galaxies beyond the Local Group providing measurements of the physical conditions of gas across a wide range of galaxy types. Finally, within our own Milky Way, the ngVLA will provide a dense grid of HI absorption spectra in the cold and warm neutral medium constraining the temperature and density of atomic gas as it transitions into molecular gas. Combined with radio continuum and molecular line data from the ngVLA plus multi-wavelength data from other planned facilities, ngVLA will have a key role in understanding star-formation in the local universe while complementing future studies with the Square Kilometer Array.
We report an optical detector with tunable positive operator-valued measures (POVMs). The device is based on a combination of weak-field homodyne techniques and photon-number-resolving detection. The resulting POVMs can be continuously tuned from Fock-state projectors to a variety of phase-dependent quantum-state measurements by adjusting different system parameters such as local oscillator coupling, amplitude and phase, allowing thus not only detection but also preparation of exotic quantum states. Experimental tomographic reconstructions of classical benchmark states are presented as a demonstration of the detector capabilities.
With the help of the quantum chemistry methods we have investigated the nature of interlayer interactions between graphene fragments in different stacking arrangements (AA and AB). We found that the AB stacking pattern as the ground state of the system, is characterized by the effective inter-band orbital interactions which are barely present in the AA. Their vanishing induces electronic decoupling between the graphene layers, so that the bonding interaction $\Delta E_{oi}$ between the flakes is drastically reduced from -0.482 eV to -0.087 eV as the stacking pattern is changed from AB to AA. The effective way to improve the bonding interaction between layers preserving the same AA lattice order is to induce rotation of the layer. As the flake is rotated, the bonding interactions are improved mostly due to suppression of the Pauli repulsion which in turn increases the interlayer orbital interactions, while the inter-band part of those remain negligible on the whole range of the rotation angle. The Pauli repulsion is also found to be the main force moving apart two fragments as the stacking pattern is changed from AA to AB. This enhances the equilibrium interlayer distance, which for the AA staking is larger than the established value for the AB stacking (3.4 A)
Kagome magnet usually hosts nontrivial electronic or magnetic states drawing great interests in condensed matter physics. In this paper, we report a systematic study on transport properties of kagome magnet TmMn$_6$Sn$_6$. The prominent topological Hall effect (THE) has been observed in a wide temperature region spanning over several magnetic phases and exhibits strong temperature and field dependence. This novel phenomenon due to non-zero spin chirality indicates possible appearance of nontrival magnetic states accompanying with strong fluctuations. The planar applied field drives planar Hall effect(PHE) and anistropic magnetoresisitivity(PAMR) exhibiting sharp disconnections in angular dependent planar resistivity violating the empirical law. By using an effective field, we identify a magnetic transition separating the PAMR into two groups belonging to various magnetic states. We extended the empirical formula to scale the field and temperature dependent planar magnetoresistivity and provide the understandings for planar transport behaviors with the crossover between various magnetic states. Our results shed lights on the novel transport effects in presence of multiple nontrivial magnetic states for the kagome lattice with complicated magnetic structures.
An interpretation is suggested that a spontaneous compactification of space-time can be regarded as a topological defect in a higher-dimensional Einstein-Yang-Mills (EYM) theory. We start with $D$-dimensional EYM theory in our present analysis. A compactification leads to a $D-2$ dimensional effective action of Abelian gauge-Higgs theory. We find a "vortex" solution in the effective theory. Our universe appears to be confined in a center of a "vortex", which has $D-4$ large dimensions. In this paper we show an example with $SU(2)$ symmetry in the original EYM theory, and the resulting solution is found to be equivalent to the "instanton-induced compactification". The cosmological implication is also mentioned.
It is known that the $\gamma_{5}$ scheme of Breitenlohner and Maison (BM) in dimensional regularization requires finite counter-term renormalization to restore gauge symmetry and implementing this finite renormalization in practical calculation is a daunting task even at 1-loop order. In this paper, we show that there is a simple and straightforward method to obtain these finite counter terms by using the rightmost $\gamma_{5}$ scheme in which we move all the $\gamma_{5}$ matrices to the rightmost position before analytically continuing the dimension. For any 1-loop Feynman diagram, the difference between the amplitude regularized in the rightmost $\gamma_{5}$ scheme and the amplitude regularized in the BM scheme can be easily calculated. The differences for all 1-loop diagrams in the chiral Abelian-Higgs gauge theory and in the chiral non-Abelian gauge theory are shown to be the same as the amplitudes due to the finite counter terms that are required to restore gauge symmetry.
We show that the recent identification of X-ray emission from SN1998bw is naturally explained as synchrotron emission from a shock driven into the wind surrounding the progenitor by a mildly relativistic shell ejected by the supernova, the existence of which was inferred earlier from radio observations. X-ray observations imply a shell energy E~10^{49.7}erg, and constrain the initial shell velocity \beta*c and normalized wind mass loss rate, \dot{m}=(\dot{M}/10^{-5}M_sun/yr)/(v_w/10^3 km/s), to satisfy \beta^3*\dot{m}~10^{-1.5}. The inferred energy is consistent with energy estimates based on radio observations provided \dot{m}~0.04, in which case radio observations imply \beta~0.8, consistent with the X-ray constraint \beta^3*\dot{m}~10^{-1.5}. While X-ray observations allow to determine the parameters characterizing the pre-explosion wind and the mildly relativistic shell ejected by SN1998bw, they do not provide evidence for existence of an off-axis "standard" GRB jet associated with SN1998bw, that may have produced GRB980425. However, as recently pointed out in (astro-ph/0310320), the lack of observational signatures typically expected to be produced by such an off-axis jet on a 1yr time scale, may be due to a low \dot{m}<0.1, which implies that an off-axis jet will become observable only on >10yr time scale.
We show two Freidlin-Wentzell type Large Deviations Principles (LDP) in path space topologies (uniform and H\"older) for the solution process of McKean-Vlasov Stochastic Differential Equations (MV-SDEs) using techniques which directly address the presence of the law in the coefficients and altogether avoiding decoupling arguments or limits of particle systems. We provide existence and uniqueness results along with several properties for a class of MV-SDEs having random coefficients and drifts of super-linear growth.   As an application of our results, we establish a Functional Strassen type result (Law of Iterated Logarithm) for the solution process of a MV-SDE.
The aim of this work is to show that the moduli space $M_{10}$ introduced by O'Grady in \cite{OG1} is a $2-$factorial variety. Namely, $M_{10}$ is the moduli space of semistable sheaves with Mukai vector $v:=(2,0,-2)\in H^{ev}(X,\mathbb{Z})$ on a projective K3 surface $X$. As a corollary to our construction, we show that the Donaldson morphism gives a Hodge isometry between $v^{\perp}$ (sublattice of the Mukai lattice of $X$) and its image in $H^{2} (\widetilde{M}_{10},\mathbb{Z})$, lattice with respect to the Beauville form of the $10-$dimensional irreducible symplectic manifold $\widetilde{M}_{10}$, obtained as symplectic resolution of $M_{10}$. Similar results are shown for the moduli space $M_{6}$ introduced by O'Grady in \cite{OG2}.
We present multiwavelength studies of the 106.6 ms gamma-ray pulsar PSR J1907+06 near the TeV source MGRO J1908+06. Timing observations with Fermi result in a precise position determination for the pulsar of R.A. = 19h07m547(2), decl. = +06:02:16(2) placing the pulsar firmly within the TeV source extent, suggesting the TeV source is the pulsar wind nebula of PSR J1907+0602. Pulsed gamma-ray emission is clearly visible at energies from 100 MeV to above 10 GeV. The phase-averaged power-law index in the energy range E > 0.1 GeV is = 1.76 \pm 0.05 with an exponential cutoff energy E_{c} = 3.6 \pm 0.5 GeV. We present the energy-dependent gamma-ray pulsed light curve as well as limits on off-pulse emission associated with the TeV source. We also report the detection of very faint (flux density of ~3.4 microJy) radio pulsations with the Arecibo telescope at 1.5 GHz having a dispersion measure DM = 82.1 \pm 1.1 cm^{-3}pc. This indicates a distance of 3.2 \pm 0.6 kpc and a pseudo-luminosity of L_{1400} ~ 0.035 mJy kpc^2. A Chandra ACIS observation revealed an absorbed, possibly extended, compact <(4 arcsec) X-ray source with significant non-thermal emission at R.A. = 19h07m54.76, decl. = +06:02:14.6 with a flux of 2.3^{+0.6}_{-1.4} X 10^{-14} erg cm^{-2} s^{-1}. From archival ASCA observations, we place upper limits on any arcminute scale 2--10 keV X-ray emission of ~ 1 X 10^{-13} erg cm^{-2} s^{-1}. The implied distance to the pulsar is compatible with that of the supernova remnant G40.5-0.5, located on the far side of the TeV nebula from PSR J1907+0602, and the S74 molecular cloud on the nearer side which we discuss as potential birth sites.
We study the periodic Cauchy problem for an integrable equation with cubic nonlinearities introduced by V. Novikov. Like the Camassa-Holm and Degasperis-Procesi equations, Novikov's equation has Lax pair representations and admits peakon solutions, but it has nonlinear terms that are cubic, rather than quadratic. We show the local well-posedness of the problem in Sobolev spaces and existence and uniqueness of solutions for all time using orbit invariants. Furthermore we prove a Cauchy-Kowalevski type theorem for this equation, that establishes the existence and uniqueness of real analytic solutions.
We introduce a new family of finite posets which we call 2-chains. These first arose in the study of 0-Hecke algebras, but they admit a variety of different characterisations. We give these characterisations, prove that they are equivalent and derive some numerical results concerning 2-chains.
A possible roadmap for reaching a status of complete information in $\gamma p \rightarrow K^ {+} \Lambda$ is outlined.
Two interesting questions in algebraic geometry are: (i) how can a smooth projective varieties degenerate? and (ii) given two such degenerations, when can we say that one is "more singular/degenerate" than the other? Schmid's Nilpotent Orbit Theorem yields Hodge-theoretic analogs of these questions, and the Hodge-theoretic answers in turn provide insight into the motivating algebro-geometric questions, sometimes with applications to the study of moduli. Recently the Hodge-theoretic questions have been completely answered. This is an expository survey of that work.
Completely positive graphs have been employed to associate with completely positive matrices for characterizing the intrinsic zero patterns. As tensors have been widely recognized as a higher-order extension of matrices, the multi-hypergraph, regarded as a generalization of graphs, is then introduced to associate with tensors for the study of complete positivity. To describe the dependence of the corresponding zero pattern for a special type of completely positive tensors--the $\{0,1\}$ completely positive tensors, the completely positive multi-hypergraph is defined. By characterizing properties of the associated multi-hypergraph, we provide necessary and sufficient conditions for any $(0,1)$ associated tensor to be $\{0,1\}$ completely positive. Furthermore, a necessary and sufficient condition for a uniform multi-hypergraph to be completely positive multi-hypergraph is proposed as well.
We propose an effective model to describe the $A_{2g}$ signal in Raman scattering experiments in the URu$_{2}$Si$_{2}$ compound. We follow the scheme proposed earlier by Khveshchenko and Wiegmann [Phys. Rev. Lett. 73, 500 (1994)] to calculate the $A_{2g}$ scattering vertex. We extract the imaginary part of a two-point current-current correlation function and compare it directly with the Raman response. We obtain an inelastic peak at $A_{2g}$ channel owing to the interplay between a local staggered ordering and a possible quantum spin liquid behavior. Our results offer an explanation for the electronic Raman scattering experiments at the hidden order phase in URu$_{2}$Si$_{2}$ compound [Phys. Rev. Lett. 113, 266405 (2014)].
We analytically explore the effect of falling matter on a spherically symmetric wormhole supported by a spherical shell composed of exotic matter located at its throat. The falling matter is assumed to be also a thin spherical shell concentric with the shell supporting the wormhole, and its self-gravity is completely taken into account. We treat these spherical thin shells by Israel's formalism of metric junction. When the falling spherical shell goes through the wormhole, it necessarily collides with the shell supporting the wormhole. To treat this collision, we assume the interaction between these shells is only gravity. We show the conditions on the parameters that characterize this model in which the wormhole persists after the spherical shell goes through it.
In this letter we present a study of the color magnitude relation of 468 early-type galaxies in the Virgo Cluster with Sloan Digital Sky Survey imaging data. The analysis of our homogeneous, model-independent data set reveals that, in all colors (u-g, g-r, g-i, i-z) similarly, giant and dwarf early-type galaxies follow a continuous color magnitude relation (CMR) that is best described by an S-shape. The magnitude range and quality of our data allows us to clearly confirm that the CMR in Virgo is not linear. Additionally, we analyze the scatter about the CMR and find that it increases in the intermediate-luminosity regime. Nevertheless, despite this observational distinction, we conclude from the similarly shaped CMR of semi-analytic model predictions that dwarfs and giants could be of the same origin.
We consider a supercritical catalytic branching random walk (CBRW) on a multidimensional lattice Z^d (d is positive integer). The main subject of study is the behavior of particles cloud in space and time. For CBRW on an integer line, Carmona and Hu (2014) examined the asymptotical behavior of the maximal coordinate M_n of the particles at time n. They proved that M_n/n converges to \mu almost surely (on a set of local non-degeneracy of CBRW), as n tends to infinity, where \mu>0 is a certain constant. Under additional assumption of a single catalyst in CBRW they also investigated the fluctuations of M_n with respect to \mu n, as n grows to infinity. Bulinskaya (2018) extended the strong limit theorem by Carmona and Hu having estimated the rate of the population propagation for the front of a multidimensional CBRW. Now our aim is to analyze fluctuations of the propagation front in CBRW on Z^d. We not only solve the problem in a multidimensional setting but also, treating the case of an arbitrary finite number of catalysts for d = 1, generalize the result by Carmona and Hu with the help of other probabilistic-analytic methods.   Keywords and phrases: catalytic branching random walk, supercritical regime, spread of population, propagation front, fluctuations of front.
A statistical analysis of the elastic unpolarized electron proton scattering data shows that, at large momentum transfer, the size and the $\epsilon$ dependence of the radiative corrections, as traditionally calculated and applied, may induce large correlations of the parameters of the Rosenbluth fit, which prevent a correct extraction of the electric proton form factor. Using the electron QED structure (radiation) function approach the cross section of elastic electron-proton scattering in leading and next-to leading approximations is calculated and expressed as a correction to the Born cross section, which is different for the electric and the magnetic contribution. When properly applied to the data, it may give the solution to the problem of the discrepancy of the polarized and unpolarized results on electron proton scattering.