Entanglement entropy of integer Quantum Hall states

We compute the entanglement entropy, in real space, of the ground state of the integer Quantum Hall states for three different domains embedded in the torus, the disk and the sphere. We establish the validity of the area law with a vanishing value of the topological entanglement entropy. The entropy per unit length of the perimeter depends on the filling fraction, but it is independent of the geometry.Comment: 5 pages, 2 figures, minor changes, one reference adde

Edge excitations of the Chern Simons matrix theory for the FQHE

We study the edge excitations of the Chern Simons matrix theory, describing the Laughlin fluids for filling fraction $\nu=\frac{1}{k}$, with $k$ an integer. Based on the semiclassical solutions of the theory, we are able to identify the bulk and edge degrees of freedom. In this way we can freeze the bulk of the theory, to the semiclassical values, obtaining an effective theory governing the boundary excitations of the Chern Simons matrix theory. Finally, we show that this effective theory is equal to the chiral boson theory on the circle.Comment: 22 pages. Section 3.2. improved. 2 Appendices added. Accepted for publication in JHE

Central galaxies in different environments: Do they have similar properties?

We perform an exhaustive comparison among central galaxies from SDSS catalogs in different local environments at 0.01<=z<=0.08. The central galaxies are separated into two categories: group centrals (host halos containing satellites) and field centrals (host halos without satellites). From the latter, we select other two subsamples: isolated centrals and bright field centrals, both with the same magnitude limit. The stellar mass (Ms) distributions of the field and group central galaxies are different, which explains why in general the field central galaxies are mainly located in the blue cloud/star forming regions, whereas the group central galaxies are strongly biased to the red sequence/passive regions. The isolated centrals occupy the same regions as the bright field centrals since both populations have similar Ms distributions. At parity of Ms, the color and specific star formation rate (sSFR) distributions of the samples are similar, specially between field and group centrals. Furthermore, we find that the stellar-to-halo mass (Ms-Mh) relation of isolated galaxies does not depend on the color, sSFR and morphological type. For systems without satellites, the Ms-Mh relation steepens at high halo masses compared to group centrals, which is a consequence of assuming a one-to-one relation between group total stellar mass and halo mass. Under the same assumption, the scatter around the Ms-Mh relation of centrals with satellites increases with halo mass. Our results suggest that the mass growth of central galaxies is mostly driven by the halo mass, with environment and mergers playing a secondary role.Comment: 17 pages, 11 figures after last Referee's report. Accepted for publication in Ap

Neural-Network Quantum States, String-Bond States, and Chiral Topological States

Neural-Network Quantum States have been recently introduced as an Ansatz for describing the wave function of quantum many-body systems. We show that there are strong connections between Neural-Network Quantum States in the form of Restricted Boltzmann Machines and some classes of Tensor-Network states in arbitrary dimensions. In particular we demonstrate that short-range Restricted Boltzmann Machines are Entangled Plaquette States, while fully connected Restricted Boltzmann Machines are String-Bond States with a nonlocal geometry and low bond dimension. These results shed light on the underlying architecture of Restricted Boltzmann Machines and their efficiency at representing many-body quantum states. String-Bond States also provide a generic way of enhancing the power of Neural-Network Quantum States and a natural generalization to systems with larger local Hilbert space. We compare the advantages and drawbacks of these different classes of states and present a method to combine them together. This allows us to benefit from both the entanglement structure of Tensor Networks and the efficiency of Neural-Network Quantum States into a single Ansatz capable of targeting the wave function of strongly correlated systems. While it remains a challenge to describe states with chiral topological order using traditional Tensor Networks, we show that Neural-Network Quantum States and their String-Bond States extension can describe a lattice Fractional Quantum Hall state exactly. In addition, we provide numerical evidence that Neural-Network Quantum States can approximate a chiral spin liquid with better accuracy than Entangled Plaquette States and local String-Bond States. Our results demonstrate the efficiency of neural networks to describe complex quantum wave functions and pave the way towards the use of String-Bond States as a tool in more traditional machine-learning applications.Comment: 15 pages, 7 figure

Ensayo de enraizamiento de estacas de murtilla (Ugni milinae Turcz.) de dos procedencias de la VII Region.

80 p.En el presente estudio se realizó un ensayo en condiciones controladas de invernadero para comparar la capacidad rizogénica de estacas de dos procedencias, de Ugni molinae Turcz. (Murtilla). Se estudiaron dos factores: Procedencia (Cordillera Andes, Cordillera Costa) y Tratamiento (con o sin aplicación de hormona comercial en la base de la estaca). A las 12 semanas se evaluó la capacidad rizogénica en base al porcentaje de enraizamiento, porcentaje de sobrevivencia, longitud de raíz primaria, número de raicillas, peso seco del brote aéreo y peso seco de las raíces. Ambos factores afectaron significativamente la capacidad de enraizamiento. El mejor resultado se logró con plantas procedentes de la Cordillera de los Andes tratadas con hormonas con un 96.66%. La sobrevivencia presentó diferencias significativas sólo a nivel de procedencia, obteniéndose una tasa de mortalidad nula, para plantas de la Cordillera de los Andes, mientras que para las procedentes de la Cordillera de la Costa, el mejor índice fue de 99.16%, tratadas con Hormonas comerciales. ii Las tres variables relacionadas con la calidad del sistema radical, denotaron diferencias significativas respecto de la procedencia y el tratamiento. Los mejores resultados se obtuvieron con plantas procedentes de la Cordillera de los Andes, tratadas con Hormona comercial, con 4.64 cm de longitud de la raíz mayor, con un número promedio de raicillas de 7.27 raíces/estaca y un peso seco de raíz de 0.034 gr. El peso seco del brote aéreo no fue afectado por los factores estudiados

Back to the edge: relative coordinate system for use-wear analysis

Use-wear studies rely heavily on experiments and reference collections to infer the function of archeological artifacts. Sequential experiments, in particular, are necessary to understand how use-wear develops. Consequently, it is crucial to analyze the same location on the tool's surface during the course of an experiment. Being able to relocate the area of interest on a sample is also essential for reproducibility in use-wear studies. However, visual relocation has limited applicability and there is currently no easy and efficient alternative. Here we propose a simple protocol to create a coordinate system directly on the sample. Three ceramic beads that serve as reference markers are adhered onto the sample, either with epoxy resin or acrylic polymer. The former is easier to work with but the latter is reversible so it can be applied to archeological samples too. The microscope's software then relocates the position(s) of interest. We demonstrate the feasibility of this approach and measure its repeatability by imaging the same position on an experimental flint blade 10 times with two confocal microscopes. Our results show that the position can be relocated automatically with a horizontal positional repeatability of approximately 14% of the field of view. Quantitative surface texture measurements according to ISO 25178 vary due to this positional inaccuracy, but it is still unknown whether this variation would mask functional differences. Although still perfectible, we argue that this protocol represents an important step toward repeatability and reproducibility in experimental archeology, especially in use-wear studies.Funding Agency Romisch-Germanisches Zentralmuseum - Leibniz Research Institute for Archeology by German Federal and Rhineland Palatinate funding (Sondertatbestand "Spurenlabor")info:eu-repo/semantics/publishedVersio