2,066 research outputs found
Interface Contributions to Topological Entanglement in Abelian Chern-Simons Theory
We study the entanglement entropy between (possibly distinct) topological
phases across an interface using an Abelian Chern-Simons description with
topological boundary conditions (TBCs) at the interface. From a microscopic
point of view, these TBCs correspond to turning on particular gapping
interactions between the edge modes across the interface. However, in studying
entanglement in the continuum Chern-Simons description, we must confront the
problem of non-factorization of the Hilbert space, which is a standard property
of gauge theories. We carefully define the entanglement entropy by using an
extended Hilbert space construction directly in the continuum theory. We show
how a given TBC isolates a corresponding gauge invariant state in the extended
Hilbert space, and hence compute the resulting entanglement entropy. We find
that the sub-leading correction to the area law remains universal, but depends
on the choice of topological boundary conditions. This agrees with the
microscopic calculation of \cite{Cano:2014pya}. Additionally, we provide a
replica path integral calculation for the entropy. In the case when the
topological phases across the interface are taken to be identical, our
construction gives a novel explanation of the equivalence between the
left-right entanglement of (1+1)d Ishibashi states and the spatial entanglement
of (2+1)d topological phases.Comment: 36 pages, 7 figures, two appendice
Birthrates and delay times of Type Ia supernovae
Type Ia supernovae (SNe Ia) play an important role in diverse areas of
astrophysics, from the chemical evolution of galaxies to observational
cosmology. However, the nature of the progenitors of SNe Ia is still unclear.
In this paper, according to a detailed binary population synthesis study, we
obtained SN Ia birthrates and delay times from different progenitor models, and
compared them with observations. We find that the Galactic SN Ia birthrate from
the double-degenerate (DD) model is close to those inferred from observations,
while the birthrate from the single-degenerate (SD) model accounts for only
about 1/2-2/3 of the observations. If a single starburst is assumed, the
distribution of the delay times of SNe Ia from the SD model is a weak
bimodality, where the WD + He channel contributes to the SNe Ia with delay
times shorter than 100Myr, and the WD + MS and WD + RG channels to those with
age longer than 1Gyr.Comment: 11 pages, 2 figures, accepted by Science in China Series G (Dec.30,
2009
Generalized joint density of states and its application to exploring the pairing symmetry of superconductors
We introduce a generalized joint density of states (GJDOS), which
incorporates the coherent factor into the JDOS, to study quasiparticle
interference (QPI) in superconductors. The intimate relation between the
Fourier-transformed local density of states and GJDOS is revealed: they corre-
spond respectively to the real and imaginary parts of a generalized
impurity-response function, and particularly share the same angular factors and
singular boundaries, as seen from our approximate analytic results for d-wave
superconductors. Remarkably, our numerical GJDOS analysis agrees well with the
QPI patten of d-wave cuprates and s\pm-wave iron-based superconductors.
Moreover, we illustrate that the present GJDOS scenario can uncover the sign
features of the superconducting gap and thus can be used to explore the
possible pairing symmetry of the KxFe2-ySe2 superconductors.Comment: 5 pages, 3 figure
Development of a Real-Time Microchip PCR System for Portable Plant Disease Diagnosis
Rapid and accurate detection of plant pathogens in the field is crucial to prevent the proliferation of infected crops. Polymerase chain reaction (PCR) process is the most reliable and accepted method for plant pathogen diagnosis, however current conventional PCR machines are not portable and require additional post-processing steps to detect the amplified DNA (amplicon) of pathogens. Real-time PCR can directly quantify the amplicon during the DNA amplification without the need for post processing, thus more suitable for field operations, however still takes time and require large instruments that are costly and not portable. Microchip PCR systems have emerged in the past decade to miniaturize conventional PCR systems and to reduce operation time and cost. Real-time microchip PCR systems have also emerged, but unfortunately all reported portable real-time microchip PCR systems require various auxiliary instruments. Here we present a stand-alone real-time microchip PCR system composed of a PCR reaction chamber microchip with integrated thin-film heater, a compact fluorescence detector to detect amplified DNA, a microcontroller to control the entire thermocycling operation with data acquisition capability, and a battery. The entire system is 25 × 16 × 8 cm(3) in size and 843 g in weight. The disposable microchip requires only 8-µl sample volume and a single PCR run consumes 110 mAh of power. A DNA extraction protocol, notably without the use of liquid nitrogen, chemicals, and other large lab equipment, was developed for field operations. The developed real-time microchip PCR system and the DNA extraction protocol were used to successfully detect six different fungal and bacterial plant pathogens with 100% success rate to a detection limit of 5 ng/8 µl sample
Pressure-Driven DNA in Nanogroove Arrays: Complex Dynamics Leads to Length- and Topology-Dependent Separation
Anomalous coupling effects in exclusive radiative B-meson decays
The top-quark FCNC processes will be searched for at the CERN LHC, which are
correlated with the B-meson decays. In this paper, we study the effects of
top-quark anomalous interactions in the exclusive radiative and decays. With the current experimental data of
the branching ratios, the direct CP and the isospin asymmetries, bounds on the
coupling from and
from decays are derived,
respectively. The bound on from is generally compatible with that from . However, the isospin asymmetry further
restrict the phase of , and the combined bound results
in the upper limit, , which is lower than the
CDF result. For real , the upper bound on is about of the same order as the discovery
potential of ATLAS with an integrated luminosity of . For
decays, the NP contribution is enhanced by a large CKM factor
, and the constraint on coupling is rather
restrictive, . With refined
measurements to be available at the LHCb and the future super-B factories, we
can get close correlations between and the rare
decays, which will be studied directly at the LHC ATLAS and CMS.Comment: 25 pages, 15 figures, pdflate
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