Search

Do residential neighbors affect each others' schooling choices? We exploit oversubscription lotteries in Chile's centralized school admission system to identify the effect of close neighbors on application and enrollment decisions. A student is 5-7% more likely to rank a high school as their first preference and to attend that school if their closest neighbor attended it the prior year. These effects are stronger among boys and applicants with lower parents' education and prior academic achievement, measured by previous scores in national standardized tests. Lower-achieving applicants are more likely to follow neighbors when their closest neighbor's test scores are higher. A neighbor enrolling in a school with one s.d. higher school effectiveness, peer composition, or school climate induces increases of 0.02-0.04 s.d. in the applicant's attended school. Our findings suggest that targeted policies aimed at increasing information to disadvantaged families have the potential to alleviate these frictions and generate significant multiplier effects.

We theoretically investigate the localization properties of Majorana states (MSs) in proximitized, planar Josephson Junctions (JJs) oriented along different crystallographic orientations and in the presence of an in-plane magnetic field and Rashba and Dresselhaus spin-orbit couplings. We show that two types of MSs may emerge when the junction transits into the topological superconducting state. In one case, referred to as end-like MSs, the Majorana quasiparticles are mainly localized inside the normal region at the opposite ends of the junction. In contrast, edge-like MSs extend along the opposite edges of the system, perpendicular to the junction channel. We show how the MSs can transit from end-like to edge-like and vice versa by tuning the magnetic field strength and/or the superconducting phase difference across the junction. In the case of phase-unbiased JJs the transition may occur as the ground state phase difference self-adjusts its value when the Zeeman field is varied., Comment: 12 pages, 6 figures

In this work, we investigate the single-photon transport through two whispering gallery resonators (WGRs) coupled to a one-dimensional waveguide. Using Green's function formalism, we compute the transmission spectra and the photonic density of states (DOS) for the stationary states. We also obtain the formation of two types of bound states in the continuum (BICs). The first kind is localized into the WGR and are symmetry-protected BICs. In contrast, the second depends on the distance between resonators through the waveguide and is of the Fabry-Perot kind. These BICs are represented as Dirac delta functions in the local density of states. Additionally, we show that quasi-BICs manifest as sharp resonances in photonic transmission due to small symmetry-breaking perturbations. Furthermore, we investigate the dynamics of a single-photon wave packet interacting with the WGRs and analyze the mechanism for storing the wave packet in the structure formed by the WGRs and the finite waveguide between them., Comment: 14 pages and 12 figures

In the present work, we further study the computational power of virus machines (VMs in short). VMs provide a computing paradigm inspired by the transmission and replication networks of viruses. VMs consist of process units (called hosts) structured by a directed graph whose arcs are called channels and an instruction graph that controls the transmissions of virus objects among hosts. The present work complements our understanding of the computing power of VMs by introducing normal forms; these expressions restrict the features in a given computing model. Some of the features that we restrict in our normal forms include (a) the number of hosts, (b) the number of instructions, and (c) the number of virus objects in each host. After we recall some known results on the computing power of VMs we give our normal forms, such as the size of the loops in the network, proving new characterisations of family of sets, such as the finite sets, semilinear sets, or NRE.

In this paper, we investigate the influence of Majorana bound states on the Fano-Rashba effect in a two-channel Fano-Anderson model. Employing Green's function formalism and the equation of motion method, we compute the transmission through the quantum dot and the density of states. Our analysis reveals that the Majorana bound states, localized at the ends of the topological superconductor nanowire, penetrate into the quantum dot, thereby altering the interference pattern in the electronic transmission profile through it, resulting from their interaction with the bound states in the continuum. Furthermore, we explore the robustness of the bound state in the continuum concerning its connection to Majorana bound states and the energy induced by the magnetic field. We posit that our findings contribute to a deeper comprehension of the Fano-Rashba effect in a two-channel quantum dot coupled to a topological superconducting nanowire., Comment: 8 pages, 6 figures

The immaculate Hecke poset was introduced and investigated by Niese, Sundaram, van Willigenburg, Vega and Wang, who established the full poset structure, and determined modules for the 0-Hecke algebra action on immaculate and row-strict immaculate tableaux. In this paper, we extend their results by introducing the skew immaculate Hecke poset. We investigate the poset structure, and construct modules for the 0-Hecke algebra action on skew immaculate and skew row-strict immaculate tableaux, thus showing that the skew immaculate Hecke poset captures representation-theoretic information analogous to the immaculate Hecke poset. We also describe branching rules for the resulting skew modules., Comment: 33 pages, 1 figure, 1 table

The parallel simulation of Spiking Neural P systems is mainly based on a matrix representation, where the graph inherent to the neural model is encoded in an adjacency matrix. The simulation algorithm is based on a matrix-vector multiplication, which is an operation efficiently implemented on parallel devices. However, when the graph of a Spiking Neural P system is not fully connected, the adjacency matrix is sparse and hence, lots of computing resources are wasted in both time and memory domains. For this reason, two compression methods for the matrix representation were proposed in a previous work, but they were not implemented nor parallelized on a simulator. In this paper, they are implemented and parallelized on GPUs as part of a new Spiking Neural P system with delays simulator. Extensive experiments are conducted on high-end GPUs (RTX2080 and A100 80GB), and it is concluded that they outperform other solutions based on state-of-the-art GPU libraries when simulating Spiking Neural P systems.

We study the lattice of submonoids of the uniform block permutation monoid containing the symmetric group (which is its group of units). We prove that this lattice is distributive under union and intersection by relating the submonoids containing the symmetric group to downsets in a new partial order on integer partitions. Furthermore, we show that the sizes of the $\mathscr{J}$-classes of the uniform block permutation monoid are sums of squares of dimensions of irreducible modules of the monoid algebra., Comment: 15 pages

Sliding bilayers are systems that exploit the possibility of relatively translating two monolayers along a specific direction in real space, such that different stackings could be implemented in the process. This simple approach allows for manipulating the electronic properties of layered materials similarly as in twisted multilayers. In this work, the sliding of bilayers, composed of one type of monolayer with spatial symmetry described by space group P$\bar{3}1m$ is studied. Using a minimal tight-binding model along with symmetry analysis, we propose two effects that arise in a specific sliding direction. First, the sliding-induced control of the band gap magnitude, which produces a metal-insulator transition, is demonstrated. In addition, the potential to achieve a topological adiabatic charge pump for cyclic sliding is discussed. For each effect, we also present material implementations using first-principles calculations. Bilayer GaS is selected for the metal-insulator transition and bilayer transition metal dichalcogenide ZrS$_2$ is found to display the topological pump effect. Both realizations show good agreement with the predictions of the model., Comment: 9 pages, 3 figures + Supplementary information

We have developed a novel, compact and cost-effective magneto-optical method for quantifying the spin-orbit torque (SOT) effective field vector (hSO) in magnetic thin films subjected to spin current injection. The damping-like (hSODL) component of the vector is obtained by the polar Kerr response arising from the out-of-plane magnetization tilting, whereas the field-like component (hSODL) is obtained by current-induced hysteresis-loop shifting study, using conventional longitudinal Kerr magnetometry. We tested our method in FM/NM bilayers comprising NiFe, CoFeB (ferromagnetic layers) and Pt, Pd, Ta (non-magnetic layers). Our findings revealed a damping-like SOT efficiency xiDL of 0.089 pm 0.006,0.019 pm 0.002, and -0.132 pm 0.009 for Pt, Pd, and Ta, respectively. The hSOFL/hSODL ratio was 0.35 pm 0.02 for NiFe/Pt and 0.14 pm 0.002 for Ta/CoFeB bilayers when the ferromagnetic layer thickness is 4nm. A key advancement over the state-of-art magneto-optical methods is the use of an oblique light incidence angle, which allows switching between measuring modes for hSODL and hSOFL, without altering the experimental setup. Moreover, our approach relies exclusively on first-order Kerr effects, thereby ensuring its broad applicability to any type of ferromagnetic material., Comment: 6 pages, 3 figures, 1 table

The Polynomial Affine Gravity is an alternative gravitational model, where the interactions are mediated solely by the affine connection, instead of the metric tensor. In this paper, we explore the space of solutions to the field equations when the torsion fields are turned on, in a homogeneous and isotropic (cosmological) scenario. We explore various metric structures that emerge in the space of solutions., Comment: EPJC format, 11 pages. v2: improved discussion, additional references

Marstrand's celebrated projection theorem gives the Hausdorff dimension of the orthogonal projection of a Borel set in Euclidean space for almost all orthogonal projections. It is straightforward to see that sets for which the Fourier and Hausdorff dimension coincide have no exceptional projections, that is, \emph{all} orthogonal projections satisfy the conclusion of Marstrand's theorem. With this in mind, one might believe that the Fourier dimension (or at least, Fourier decay) could be used to give better estimates for the Hausdorff dimension of the exceptional set in general. We obtain projection theorems and exceptional set estimates based on the Fourier spectrum; a family of dimensions that interpolates between the Fourier and Hausdorff dimensions. We apply these results to show that the Fourier spectrum can be used to improve several results for the Hausdorff dimension in certain cases, such as Ren--Wang's sharp bound for the exceptional set in the plane, Peres--Schlag's exceptional set bound and Bourgain--Oberlin's sharp $0$-dimensional exceptional set estimate., Comment: 23 pages, 3 figures. Some improvements

We study Stanley's chromatic symmetric function (CSF) for trees when expressed in the star-basis. We use the deletion-near-contraction algorithm recently introduced in \cite{ADOZ} to compute coefficients that occur in the CSF in the star-basis. In particular, one of our main results determines the smallest partition in lexicographic order that occurs as an indexing partition in the CSF, and we also give a formula for its coefficient. In addition to describing properties of trees encoded in the coefficients of the star-basis, we give two main applications of the leading coefficient result. The first is a strengthening of the result in \cite{ADOZ} that says that proper trees of diameter less than or equal to 5 can be reconstructed from their CSFs. In this paper we show that this is true for all trees of diameter less than or equal 5. In our second application, we show that the dimension of the subspace of symmetric functions spanned by the CSF of $n$-vertex trees is $p(n)-n+1$, where $p(n)$ is the number of partitions of $n$., Comment: 36 pages, 8 figures

It is an important problem in algebraic combinatorics to deduce the Schur function expansion of a symmetric function whose expansion in terms of the fundamental quasisymmetric function is known. For example, formulas are known for the fundamental expansion of a Macdonald symmetric function and for the plethysm of two Schur functions, while the Schur expansions of these expressions are still elusive. Egge, Loehr and Warrington provided a method to obtain the Schur expansion from the fundamental expansion by replacing each quasisymmetric function by a Schur function (not necessarily indexed by a partition) and using straightening rules to obtain the Schur expansion. Here we provide a new method that only involves the coefficients of the quasisymmetric functions indexed by partitions and the quasi-Kostka matrix. As an application, we identify the lexicographically largest term in the Schur expansion of the plethysm of two Schur functions. We provide the Schur expansion of $s_w[s_h](x,y)$ for $w=2,3,4$ using novel symmetric chain decompositions of Young's lattice for partitions in a $w\times h$ box. For $w=4$, this is first known combinatorial expression for the coefficient of $s_{\lambda}$ in $s_{w}[s_{h}]$ for two-row partitions $\lambda$, and for $w=3$ the combinatorial expression is new., Comment: 27 pages; 5 figures

Bound states in the continuum (BICs) are exotic, localized states even though their energy lies in the continuum spectra. Since its discovery in 1929, the quest to unveil these exotic states in charge transport experiments remains an active pursuit in condensed matter physics. Here, we study charge transport in InSb nanowire networks in the ballistic regime and subject to a perpendicular magnetic field as ideal candidates to observe and control the appearance of BICs. We find that BICs reveal themselves as distinctive resonances or antiresonances in the conductance by varying the applied magnetic field and the Fermi energy. We systematically consider different lead connections in hashtag-like nanowire networks, finding the optimal configuration that enhances the features associated with the emergence of BICs. Finally, the investigation focuses on the effect of the Rashba spin-orbit interaction of InSb on the occurrence of BICs in nanowire networks. While the interaction generally plays a detrimental role in the signatures of the BICs in the conductance of the nanowire networks, it opens the possibility to operate these nanostructures as spin filters for spintronics. We believe that this work could pave the way for the unambiguous observation of BICs in charge transport experiments and for the development of advanced spintronic devices., Comment: 9 pages, 6 figures, supplementary material. Submission to SciPost

The Fourier spectrum is a family of dimensions that interpolates between the Fourier and Hausdorff dimensions and are defined in terms of certain energies which capture Fourier decay. In this paper we obtain a convenient discrete representation of those energies using the Fourier coefficients. As an example application, we use this representation to establish sharp bounds for the Fourier spectrum of a general measure with bounded support, improving previous estimates of the second-named author, Comment: 13 pages

Quantum rings coupled to external nanowires offer a versatile platform for the manipulation of the quantum mesoscopic transport. Here, we study such a system, including periodically distributed pointlike impurities along the ring. Based on an exact expression for the conductance found here, we demonstrate that the bound states in the continuum (BICs) form from the ring states at the high-symmetry momenta in the ring's Brillouin zone. Furthermore, the presence of the inversion symmetry allows for a selective decoupling of resonant states, favoring the BIC generation and, therefore, allowing extra tunability in the quantum transport of the system. Finally, we suggest that the magnetic fluxes and Rashba spin-orbit coupling offer other possible routes for the BIC formation in laterally coupled quantum rings., Comment: 6 pages, 4 figures, supplementary material as ancillary file, typos corrected, references added

Over the last few decades, the study of Bound States in the Continuum, their formation, and properties has attracted lots of attention, especially in optics and photonics. It is particularly noticeable that most of these investigations base their studies on symmetric systems. In this article, we study the formation of bound states in the continuum in electronic and photonic transport systems consisting of crossbar junctions formed by one-dimensional waveguides, considering asymmetric junctions with commensurable lengths for the upper and lower arms. We also study how BICs form in linear junction arrays as a function of the distance between consecutive junctions and their commensurability with the upper and lower arms. We solve the Helmholtz equation for the crossbar junctions and calculate the transmission probability, probability density in the intersections, and quality factor. The presence of quasi-BICs is reflected in the transmission probability as a sharp resonance in the middle of a symmetric Fano resonance along with Dirac's delta functions in the probability density and divergence in the quality factors., Comment: 12 pages, 12 figures

In this work we report on a new version of FeynCalc, a Mathematica package widely used in the particle physics community for manipulating quantum field theoretical expressions and calculating Feynman diagrams. Highlights of the new version include greatly improved capabilities for doing multiloop calculations, including topology identification and minimization, optimized tensor reduction, rewriting of scalar products in terms of inverse denominators, detection of equivalent or scaleless loop integrals, derivation of Symanzik polynomials, Feynman parametric as well as graph representation for master integrals and initial support for handling differential equations and iterated integrals. In addition to that, the new release also features completely rewritten routines for color algebra simplifications, inclusion of symmetry relations between arguments of Passarino--Veltman functions, tools for determining matching coefficients and quantifying the agreement between numerical results, improved export to LaTeX and first steps towards a better support of calculations involving light-cone vectors., Comment: 51 pages, no figures, updated to match the journal version. To obtain the program, see https://github.com/FeynCalc/feyncalc

In order to understand galaxy growth evolution, it is critical to constrain the evolution of its building block: gas. Mostly comprised by Hydrogen in its neutral (HI) and molecular (H2) phases, the latter is the one mostly directly associated to star-formation, while the neutral phase is considered the long-term gas reservoir. In this work, we make use of an empirical relation between dust emission at millimeter wavelengths and total gas mass in the inter-stellar medium (M_HI plus M_H2) in order to retrieve the HI content in galaxies. We assemble an heterogeneous sample of 335 galaxies at 0.011E10.5M_sun significantly decreased since 8-12Gyr ago. The specific sample used for this analysis is associated to 20-50% of the total cosmic HI content as estimated via Damped Lyman-alpha Absorbers. In IR luminous galaxies, HI mass content decreases between z~2.5 and z~1.5, while H2 seems to increase. We also show source detection expectations for SKA surveys., Comment: Incorporated feedback obtained during ALMA-10yr conference and via email. Submitted to MNRAS. Main text 13 pages. Comments are welcomed