10,729 research outputs found
Plusiotis ericsmithi (Coleoptera: Scarabaeidae) : a new metallic species from eastern Guatemala
Se describe Plusiotis ericsmithi sp. nov. de un bosque nuboso de baja altitud (1100 msnm) en la Sierra del Merend6n, Guatemala, cerca de la front era con Honduras. Ademas, se incluyen ilustraciones de los genitales masculinos y femeninos.Plusiotis ericsmithii n. sp. is described from a low altitude cloud forest (1100 m) in the Guatemalan
Merend6n mountain chain near the Honduran border. Male and female genitalia are illustrated
Quantum spin models for the SU(n)_1 Wess-Zumino-Witten model
We propose 1D and 2D lattice wave functions constructed from the SU(n)_1
Wess-Zumino-Witten (WZW) model and derive their parent Hamiltonians. When all
spins in the lattice transform under SU(n) fundamental representations, we
obtain a two-body Hamiltonian in 1D, including the SU(n) Haldane-Shastry model
as a special case. In 2D, we show that the wave function converges to a class
of Halperin's multilayer fractional quantum Hall states and belongs to chiral
spin liquids. Our result reveals a hidden SU(n) symmetry for this class of
Halperin states. When the spins sit on bipartite lattices with alternating
fundamental and conjugate representations, we provide numerical evidence that
the state in 1D exhibits quantum criticality deviating from the expected
behaviors of the SU(n)_1 WZW model, while in 2D they are chiral spin liquids
being consistent with the prediction of the SU(n)_1 WZW model.Comment: 28 pages, 9 figures, published versio
Notes on Guatemalan Plusiotis (Coleoptera: Scarabaeidae; Rutelinae)
Dos especies nuevas de escarabajos del genero Plusiotis se describen de un bosque nuboso, 1560-1900 m en el departamento de San Marcos, Guatemala. Tambien se describen las hembras de P. turhheimi Ohaus, P. auropunctata Ohaus y P. quiche Moron. Ademas, se registra pOI' primera vez a P. turhheimi para Guatemala.Two new species of Plusiotis are described from a cloud forest between 1560-1900 m in the Department of San Marcos, Guatemala. Females of P. turhheimi Ohaus, P. auropunctata Ohaus and P. quiche Moron are described. Plusiotis turhheimi is reported from Guatemala for the first time
Optical lattice implementation scheme of a bosonic topological model with fermionic atoms
We present a scheme to implement a Fermi-Hubbard-like model in ultracold
atoms in optical lattices and analyze the topological features of its ground
state. In particular, we show that the ground state for appropriate parameters
has a large overlap with a lattice version of the bosonic Laughlin state at
filling factor one half. The scheme utilizes laser assisted and normal
tunnelling in a checkerboard optical lattice. The requirements on temperature,
interactions, and hopping strengths are similar to those needed to observe the
N\'eel antiferromagnetic ordering in the standard Fermi-Hubbard model in the
Mott insulating regime.Comment: 18 pages, 10 figures. This article provides the full analysis of a
scheme proposed in Nat. Commun. 4, 2864 (2013). v2: accepted versio
Construction of spin models displaying quantum criticality from quantum field theory
We provide a method for constructing finite temperature states of
one-dimensional spin chains displaying quantum criticality. These models are
constructed using correlators of products of quantum fields and have an
analytical purification. Their properties can be investigated by Monte-Carlo
simulations, which enable us to study the low-temperature phase diagram and to
show that it displays a region of quantum criticality. The mixed states
obtained are shown to be close to the thermal state of a simple nearest
neighbour Hamiltonian.Comment: 10 pages, 6 figure
Bosonic Gaussian states from conformal field theory
We study nonchiral wave functions for systems with continuous spins obtained
from the conformal field theory (CFT) of a free, massless boson. In contrast to
the case of discrete spins, these can be treated as bosonic Gaussian states,
which allows us to efficiently compute correlations and entanglement properties
both in one (1D) and in two spatial dimensions (2D). In 1D, the computed
entanglement entropy and spectra are in agreement with the underlying CFT.
Furthermore, we construct a 1D parent Hamiltonian with a low-energy spectrum
corresponding to that of a free, massless boson. In 2D, we find edge
excitations in the entanglement spectrum, although the states do not have
intrinsic topological order, as revealed by a determination of the topological
entanglement entropy.Comment: 18 pages, 8 figures, v2: accepted versio
Lattice effects on Laughlin wave functions and parent Hamiltonians
We investigate lattice effects on wave functions that are lattice analogues
of bosonic and fermionic Laughlin wave functions with number of particles per
flux in the Landau levels. These wave functions are defined
analytically on lattices with particles per lattice site, where may
be different than . We give numerical evidence that these states have the
same topological properties as the corresponding continuum Laughlin states for
different values of and for different fillings . These states define,
in particular, particle-hole symmetric lattice Fractional Quantum Hall states
when the lattice is half-filled. On the square lattice it is observed that for
this particle-hole symmetric state displays the topological
properties of the continuum Laughlin state at filling fraction , while
for larger there is a transition towards long-range ordered
anti-ferromagnets. This effect does not persist if the lattice is deformed from
a square to a triangular lattice, or on the Kagome lattice, in which case the
topological properties of the state are recovered. We then show that changing
the number of particles while keeping the expression of these wave functions
identical gives rise to edge states that have the same correlations in the bulk
as the reference lattice Laughlin states but a different density at the edge.
We derive an exact parent Hamiltonian for which all these edge states are
ground states with different number of particles. In addition this Hamiltonian
admits the reference lattice Laughlin state as its unique ground state of
filling factor . Parent Hamiltonians are also derived for the lattice
Laughlin states at other fillings of the lattice, when or
and when also at half-filling.Comment: 18 pages, 15 figure
- …