Percolation properties of growing networks under an Achlioptas process

We study the percolation transition in growing networks under an Achlioptas process (AP). At each time step, a node is added in the network and, with the probability $\delta$, a link is formed between two nodes chosen by an AP. We find that there occurs the percolation transition with varying $\delta$ and the critical point $\delta_c=0.5149(1)$ is determined from the power-law behavior of order parameter and the crossing of the fourth-order cumulant at the critical point, also confirmed by the movement of the peak positions of the second largest cluster size to the $\delta_c$. Using the finite-size scaling analysis, we get $\beta/\bar{\nu}=0.20(1)$ and $1/\bar{\nu}=0.40(1)$, which implies $\beta \approx 1/2$ and $\bar{\nu} \approx 5/2$. The Fisher exponent $\tau = 2.24(1)$ for the cluster size distribution is obtained and shown to satisfy the hyperscaling relation.Comment: 4 pages, 5 figures, 1 table, journal submitte

Increasing and decreasing entanglement characteristics for continuous variables by a local photon subtraction

We investigate how the entanglement characteristics of a non-Gaussian entangled state are increased or decreased by a local photon subtraction operation. The non-Gaussian entangled state is generated by injecting a single-mode non-Gaussian state and a vacuum state into a 50:50 beam splitter. We consider a photon-added coherent state and an odd coherent state as a single-mode non-Gaussian state. In the regime of small amplitude, we show that the performance of quantum teleportation and the second-order Einstein-Podolsky- Rosen-type correlation can both be enhanced, whereas the degree of entanglement decreases, for the output state when a local photon subtraction operation is applied to the non-Gaussian entangled state. The counterintuitive effect is more prominent in the limit of nearly zero amplitude.Comment: Published version, 7 pages, 3 figure

End-of-Life management of wind turbines, PV modules and Lithium-Ion batteries: Current practices and closing the circular economy gap

Renewable energy generation and increased electrification are pivotal to reducing greenhouse gas emissions and mitigating climate change. Consequently, global deployment of wind turbines, PV modules and electric vehicles has soared, and the trend is expected to continue. These technologies have only recently started reaching the end of their design lives, and rapid escalation of end-of-life (EoL) waste volumes are projected. This study responds to the imminent waste issue by researching current EoL management practices, initiatives and regulations of these three technologies in Canada and globally. Through extensive literature review and communications with select experts in the EoL field, it also seeks to identify factors that impede current EoL management efforts to close the circular economy gap and those that can support the overall sustainability of deploying these technologies. The EoL management of these technologies is in the early stages and many innovative initiatives are being explored and developed. There are currently few proven business cases, and barriers to the EoL strategies’ profitability and effectiveness include insufficient waste feedstock, inadequate collection infrastructure and second-life markets, and uncertainty about the assets’ remaining useful life. Designing for circularity, collaboration between supply chain stakeholders, circular business models and technology-specific regulations that incorporate extended producer responsibility, second-life targets and circular solutions can help progress the technologies toward improved sustainability. The research found that EoL management is a complex but necessary undertaking that needs to consider multiple, often conflicting factors. Additionally, the technologies and their EoL management practices are dynamic and fast-changing. Hence this study's findings are best viewed as compelling evidence of the increasing need for robust EoL management and a demonstration of potential solutions rather than absolute conclusions

Quantum phase estimation using path-symmetric entangled states

We study the sensitivity of phase estimation using a generic class of path-symmetric entangled states $|\varphi\rangle|0\rangle+|0\rangle|\varphi\rangle$, where an arbitrary state $|\varphi\rangle$ occupies one of two modes in quantum superposition. This class of states includes the previously considered states, i.e. $NOON$ states and entangled coherent states, as special cases. With its generalization, we identify the practical limit of phase estimation under energy constraint that is characterized by the photon statistics of the component state $|\varphi\rangle$. We first show that quantum Cramer-Rao bound (QCRB) can be lowered with super-Poissonianity of the state $|\varphi\rangle$. By introducing a component state of the form $|\varphi\rangle=\sqrt{q}|1\rangle+\sqrt{1-q}|N\rangle$, we particularly show that an arbitrarily small QCRB can be achieved even with a finite energy in an ideal situation. For practical measurement schemes, we consider a parity measurement and a full photon-counting method to obtain phase-sensitivity. Without photon loss, the latter scheme employing any path-symmetric states $|\varphi\rangle|0\rangle+|0\rangle|\varphi\rangle$ achieves the QCRB over the entire range $[0,2\pi]$ of unknown phase shift $\phi$ whereas the former does so in a certain confined range of $\phi$. We find that the case of $|\varphi\rangle=\sqrt{q}|1\rangle+\sqrt{1-q}|N\rangle$ provides the most robust resource against loss among the considered entangled states over the whole range of input energy. Finally we also propose experimental schemes to generate these path-symmetric entangled states.Comment: 10 pages, 5 figures, published versio

Low-bias Negative Differential Resistance effect in armchair graphene nanoribbon junctions

Graphene nanoribbons with armchair edges (AGNRs) have bandgaps that can be flexibly tuned via the ribbon width. A junction made of a narrower AGNR sandwiched between two wider AGNR leads was recently reported to possess two perfect transmission channels close to the Fermi level. Here, we report that by using a bias voltage to drive these transmission channels into the gap of the wider AGNR lead, we can obtain a negative differential resistance (NDR) effect. Owing to the intrinsic properties of the AGNR junctions, the on-set bias reaches as low as ~ 0.2 V and the valley current almost vanishes. We further show that such NDR effect is robust against details of the atomic structure of the junction, substrate and whether the junction is made by etching or by hydrogenation.Comment: The following article has been submitted to Applied Physics Letters (http://scitation.aip.org/content/aip/journal/apl). Copyright (2014) Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported Licens

Plants’ responses to drought and shade environments

Water and light are the most important environements for plants’ growth. These environemts are critical factors needed not only for the survival of plants but also their production. When plants are exposed to drought condition, they change in their anatomical, physiological and biochemical properties. Drought affects plants wildly from their cell structure to growth. It causes higher plastoglobuli, lower starch grain, distortion of thylakoids, disrupted grana and swelling of chloroplast. Plants grown under enhanced light, have increased palisade parenchyma, thicker leaf, higher biomass, increased photosynthesis, lower contents of chlorophyll, carotenoid and nitrogen.Keywords: Drought, plant, shade, wate