Finite temperature phase diagram of a spin-1 Bose gas

We formulate a self-consistent Hartree-Fock theory for a spin-1 Bose gas at finite temperature and apply it to characterizing the phase diagram. We find that spin coherence between thermal atoms in different magnetic sub-levels develops via coherent collisions with the condensed atoms, and is a crucial factor in determining the phase diagram. We develop analytical expressions to characterize the interaction and temperature dependent shifts of the phase boundaries.Comment: 11 pages, 5 figure

Entanglement of purification: from spin chains to holography

Purification is a powerful technique in quantum physics whereby a mixed quantum state is extended to a pure state on a larger system. This process is not unique, and in systems composed of many degrees of freedom, one natural purification is the one with minimal entanglement. Here we study the entropy of the minimally entangled purification, called the entanglement of purification, in three model systems: an Ising spin chain, conformal field theories holographically dual to Einstein gravity, and random stabilizer tensor networks. We conjecture values for the entanglement of purification in all these models, and we support our conjectures with a variety of numerical and analytical results. We find that such minimally entangled purifications have a number of applications, from enhancing entanglement-based tensor network methods for describing mixed states to elucidating novel aspects of the emergence of geometry from entanglement in the AdS/CFT correspondence.Comment: 40 pages, multiple figures. v2: references added, typos correcte

Modeling and Analyzing Academic Researcher Behavior

. This paper suggests a theoretical framework for analyzing the mechanism of the behavior of academic researchers whose interests are tangled and vary widely in academic factors (the intrinsic satisfaction in conducting research, the improvement in individual research ability, etc.) or non-academic factors (career rewards, financial rewards, etc.). Furthermore, each researcher also has his/her different academic stances in their preferences about academic freedom and academic entrepreneurship. Understanding the behavior of academic researchers will contribute to nurture young researchers, to improve the standard of research and education as well as to boost collaboration in academia-industry. In particular, as open innovation is increasingly in need of the involvement of university researchers, to establish a successful approach to entice researchers into enterprises' research, companies must comprehend the behavior of university researchers who have multiple complex motivations. The paper explores academic researchers' behaviors through optimizing their utility functions, i.e. the satisfaction obtained by their research outputs. This paper characterizes these outputs as the results of researchers' 3C: Competence (the ability to implement the research), Commitment (the effort to do the research), and Contribution (finding meaning in the research). Most of the previous research utilized the empirical methods to study researcher's motivation. Without adopting economic theory into the analysis, the past literature could not offer a deeper understanding of researcher's behavior. Our contribution is important both conceptually and practically because it provides the first theoretical framework to study the mechanism of researcher's behavior

The fear of bad smell: Health risk awareness related to using waste in agricultural production in Vietnam

Waste watersWater reuseAgricultural productionFish farmingIrrigation waterPublic healthRisksSkin diseasesOrganic fertilizersWomen

Local and global behaviour of nonlinear equations with natural growth terms

This paper concerns a study of the pointwise behaviour of positive solutions to certain quasi-linear elliptic equations with natural growth terms, under minimal regularity assumptions on the underlying coefficients. Our primary results consist of optimal pointwise estimates for positive solutions of such equations in terms of two local Wolff's potentials.Comment: In memory of Professor Nigel Kalto

Ecohealth research to regionally address agriculture intensification impacts on health and the environment in Southeast Asia and China

Ecohealth Field Building Leadership Initiative is a regional operational research network in Southeast Asia and China that focuses on solving human health problems associated with agricultural intensification. FBLI has 3 focus areas, namely research, capacity building and knowledge translation. FBLI gathers researchers, policy makers, community members and other stakeholders from 4 focused countries (China, Indonesia, Thailand and Vietnam). Here we describe the operational research component that focuses on aspects of agriculture intensification on health and the environment including animal waste from pig production (Vietnam), dairy production (Indonesia), pesticide use in vegetable production (China), and health risks in rubber plantation (Thailand). Integrated approaches to the research component including survey, participatory and cross-cutting methods are discussed. The research results from Vietnam and Indonesia showed health and environmental impacts of manure management options, in particular the biogas system and turning waste to value. In Hanam of Vietnam, the health risks from biogas effluent reuse include E. coli infection (19–22% of population exposed) and G. lamblia infection (45–55% of population exposed). In Pangalengan, Indonesia, the Ecohealth approach was used to promote the production of medicinal worm and casting biofertilizer from cow manure as an environmentallyfriendly fertilizer alternative. In Chachoengsao Province of Thailand, key findings include evidences for higher risk of vectorborne diseases (dengue and chikungunya) in rubber plantation areas as well as higher microbial and heavy metal contamination of water and soil. In six villages of three townships in a County of Yunnan Province, China, issues identified were lack of farmer knowledge of pesticides, pesticide abuse, and ineffective policy to reduce pesticide abuse. Pesticide contamination was recorded from 6.1% to 12.7% of vegetables depending on sampling location in the field or market. The findings from 4 countries illustrate how Ecohealth research has been applied in health and agriculture and serve as basis for interventions for reduce health and environmental risks

Development of resource-saving technology for excavation of flat-lying coal seams with tight roof rocks (on the example of the Quang Ninh coal basin mines)

It is shown that the creation of the variants of resource-saving systems for the development of long-column mining is one of the main directions for improving the technological schemes for mining operations in the mines of the Kuang Nin coal basin. They provide a reduction in coal losses in the inter-column pillars and the cost of maintaining preliminary workings fixed with anchorage. The implementation of these directions is difficult (and in some cases practically impossible) when tight rocks are lying over the coal seam, prone to significant hovering in the developed space. In the Quang Ninh basin, 9-10 % of the workings are anchored, the operational losses of coal reach 30 % or more; up to 50 % of the workings are re-anchored annually. It is concluded that the real conditions for reducing coal losses and the effective use of anchor support as the main support of reusable preliminary workings are created when implementing the idea put forward at the St. Petersburg Mining University: leaving the coal pillar of increased width between the reused mine working and the developed space and its subsequent development on the same line with the stoping face simultaneously with the reclamation of the reused mine working

Short range ferromagnetism and spin glass state in Y0.7Ca0.3MnO3\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}

Dynamic magnetic properties of $\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}$ are reported. The system appears to attain local ferromagnetic order at $T_{\mathrm{SRF}} \approx 70$ K. Below this temperature the low field magnetization becomes history dependent, i.e. the zero field cooled (ZFC) and field cooled (FC) magnetization deviate from each other and closely logarithmic relaxation appears at our experimental time scales (0.3-$10^{4}$ sec). The zero field cooled magnetization has a maximum at $T_{\mathrm{f}}\approx 30$ K, whereas the field cooled magnetization continues to increase, although less sharply, also below this temperature. Surprisingly, the dynamics of the system shows non-equilibrium spin glass (SG) features not only below the maximum in the ZFC magnetization, but also in the temperature region between this maximum and $T_{\mathrm{SRF}}$. The aging and temperature cycling experiments show only quantitative differences in the dynamic behavior above and below the maximum in the ZFC-magnetization; similarly, memory effects are observed in both temperature regions. We attribute the high temperature behavior to the existence of clusters of short range ferromagnetic order below $T_{\mathrm{SRF}}$; the configuration evolves into a conventional spin glass state at temperatures below $T_{\mathrm{f}}$.Comment: REVTeX style; 8 pages, 8 figure