150 research outputs found
Entanglement scaling in two-dimensional gapless systems
We numerically determine subleading scaling terms in the ground-state
entanglement entropy of several two-dimensional (2D) gapless systems, including
a Heisenberg model with N\'eel order, a free Dirac fermion in the {\pi}-flux
phase, and the nearest-neighbor resonating-valence-bond wavefunction. For these
models, we show that the entanglement entropy between cylindrical regions of
length x and L - x, extending around a torus of length L, depends upon the
dimensionless ratio x/L. This can be well-approximated on finite-size lattices
by a function ln(sin({\pi}x/L)), akin to the familiar chord-length dependence
in one dimension. We provide evidence, however, that the precise form of this
bulk-dependent contribution is a more general function in the 2D thermodynamic
limit.Comment: 5 pages, 5 figure
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Fully gravure printed complementary carbon nanotube TFTs for a clock signal generator using an epoxy-imine based cross-linker as an n-dopant and encapsulant.
Printed p-type single walled carbon nanotube (SWCNT) based circuits exhibit high power dissipation owing to their thick printed dielectric layers (>2 μm) and long channels (>100 μm). In order to reduce the static power dissipation of printed SWCNT-base circuits while maintaining the same printing conditions and channel lengths, complementary metal-oxide-semiconductor (CMOS) based circuits are more ideal. These circuits, however, have not been successfully implemented in a scalable printing platform due to unstable threshold voltages of n-doped SWCNT based thin film transistors (TFTs). In this work, a thermally curable epoxy-imine-based n-doping ink is presented for achieving uniform doping and sealing of SWCNT layers by gravure printing. After printing the n-doping ink, the ink is cured to initiate a cross-linking reaction to seal the n-doped SWCNT-TFTs so that the threshold voltage of the n-doped SWCNT-TFTs is stabilized. Flexible CMOS ring oscillators using such n-doped SWCNT-TFTs combined with the intrinsically p-type SWCNT-TFTs can generate a 0.2 Hz clock signal with significantly lower power consumption compared to similarly printed p-type only TFT based ring oscillators. Moving forward, this CMOS flexible ring oscillator can be practically used to develop fully printed inexpensive wireless sensor tags
Influence of Fatigue, Depression and Anxiety on Quality of Life in Pregnant Women with Preterm Labor
PURPOSE: The purpose of this study was to identify effects of fatigue, depression and anxiety on quality of life in pregnant women with preterm labor.
METHODS: With a survey design, data were collected from 138 mothers who were admitted at a hospital in Seoul, between June 2014 and September 2015. Instruments used to collect the data for the study were: Fatigue Continuum Form, Depression anxiety stress scale (DASS-21) and maternal postpartum quality of life (MAPP-QOL).
RESULTS: The mean fatigue score was 68.30 with 50.7% of women being depressed and 79.7% of the 138 women being anxious. The mean quality of life was 18.92 with quality of life being associated with fatigue, depression and anxiety. Depression and fatigue explained 26% of the variance in quality of life.
CONCLUSION: Depression and fatigue adversely affected women's quality of life. It is important to address appropriate management of depression and fatigue in order to improve quality of life in pregnant women with preterm labor
Entanglement in gapless resonating valence bond states
We study resonating-valence-bond (RVB) states on the square lattice of spins
and of dimers, as well as SU(N)-invariant states that interpolate between the
two. These states are ground states of gapless models, although the
SU(2)-invariant spin RVB state is also believed to be a gapped liquid in its
spinful sector. We show that the gapless behavior in spin and dimer RVB states
is qualitatively similar by studying the R\'enyi entropy for splitting a torus
into two cylinders, We compute this exactly for dimers, showing it behaves
similarly to the familiar one-dimensional log term, although not identically.
We extend the exact computation to an effective theory believed to interpolate
among these states. By numerical calculations for the SU(2) RVB state and its
SU(N)-invariant generalizations, we provide further support for this belief. We
also show how the entanglement entropy behaves qualitatively differently for
different values of the R\'enyi index , with large values of proving a
more sensitive probe here, by virtue of exhibiting a striking even/odd effect.Comment: 44 pages, 14 figures, published versio
Electric Field-Tuned Topological Phase Transition in Ultra-Thin Na3Bi - Towards a Topological Transistor
The electric field induced quantum phase transition from topological to
conventional insulator has been proposed as the basis of a topological field
effect transistor [1-4]. In this scheme an electric field can switch 'on' the
ballistic flow of charge and spin along dissipationless edges of the
two-dimensional (2D) quantum spin Hall insulator [5-9], and when 'off' is a
conventional insulator with no conductive channels. Such as topological
transistor is promising for low-energy logic circuits [4], which would
necessitate electric field-switched materials with conventional and topological
bandgaps much greater than room temperature, significantly greater than
proposed to date [6-8]. Topological Dirac semimetals(TDS) are promising systems
in which to look for topological field-effect switching, as they lie at the
boundary between conventional and topological phases [3,10-16]. Here we use
scanning probe microscopy/spectroscopy (STM/STS) and angle-resolved
photoelectron spectroscopy (ARPES) to show that mono- and bilayer films of TDS
Na3Bi [3,17] are 2D topological insulators with bulk bandgaps >400 meV in the
absence of electric field. Upon application of electric field by doping with
potassium or by close approach of the STM tip, the bandgap can be completely
closed then re-opened with conventional gap greater than 100 meV. The large
bandgaps in both the conventional and quantum spin Hall phases, much greater
than the thermal energy kT = 25 meV at room temperature, suggest that ultrathin
Na3Bi is suitable for room temperature topological transistor operation
Cu2Se-based thermoelectric cellular architectures for efficient and durable power generation
Thermoelectric power generation offers a promising way to recover waste heat. The geometrical design of thermoelectric legs in modules is important to ensure sustainable power generation but cannot be easily achieved by traditional fabrication processes. Herein, we propose the design of cellular thermoelectric architectures for efficient and durable power generation, realized by the extrusion-based 3D printing process of Cu2Se thermoelectric materials. We design the optimum aspect ratio of a cuboid thermoelectric leg to maximize the power output and extend this design to the mechanically stiff cellular architectures of hollow hexagonal column- and honeycomb-based thermoelectric legs. Moreover, we develop organic binder-free Cu2Se-based 3D-printing inks with desirable viscoelasticity, tailored with an additive of inorganic Se-8(2-) polyanion, fabricating the designed topologies. The computational simulation and experimental measurement demonstrate the superior power output and mechanical stiffness of the proposed cellular thermoelectric architectures to other designs, unveiling the importance of topological designs of thermoelectric legs toward higher power and longer durability
Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension
OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo
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