The Tensor Networks Anthology: Simulation techniques for many-body quantum lattice systems

We present a compendium of numerical simulation techniques, based on tensor network methods, aiming to address problems of many-body quantum mechanics on a classical computer. The core setting of this anthology are lattice problems in low spatial dimension at finite size, a physical scenario where tensor network methods, both Density Matrix Renormalization Group and beyond, have long proven to be winning strategies. Here we explore in detail the numerical frameworks and methods employed to deal with low-dimension physical setups, from a computational physics perspective. We focus on symmetries and closed-system simulations in arbitrary boundary conditions, while discussing the numerical data structures and linear algebra manipulation routines involved, which form the core libraries of any tensor network code. At a higher level, we put the spotlight on loop-free network geometries, discussing their advantages, and presenting in detail algorithms to simulate low-energy equilibrium states. Accompanied by discussions of data structures, numerical techniques and performance, this anthology serves as a programmer's companion, as well as a self-contained introduction and review of the basic and selected advanced concepts in tensor networks, including examples of their applications.Comment: 115 pages, 56 figure

Two siblings with the same severe form of 21-hydroxylase deficiency but different growth and menstrual cycle patterns

Congenital adrenal hyperplasia (CAH) is one of the most frequent autosomal recessive diseases in Europe. Treatment is a challenge for pediatric endocrinologists. Important parameters to judge the outcome are adult height and menstrual cycle. We report the follow-up from birth to adulthood of two Caucasian sisters with salt-wasting CAH due to the same mutation, homozygosity c.290-13A>G (I2 splice), in the 21-hydroxylase gene. Their adherence to treatment was excellent. Our objective was to distinguish the effects of treatment with hydrocortisone (HC) and fludrocortisone (FC) on final height (FH) from constitutional factors. The older girl (patient 1), who showed virilized genitalia Prader scale III-IV at birth, reached FH within familial target height at 18 years of age. Menarche occurred at the age of 15. Her menstrual cycles were always irregular. Total pubertal growth was normal (29 cm). She showed a growth pattern consistent with constitutional delay. The younger sister (patient 2) was born without masculinization of the genitalia after her mother was treated with dexamethasone starting in the fourth week of pregnancy. She reached FH at 16 years of age. Her adult height is slightly below familial target height. Menarche occurred at the age of 12.5, followed by regular menses. Total pubertal growth was normal (21 cm). The average dose of HC from birth to FH was 16.7 mg/m2 in patient 1 and 16.8 mg/m2 in patient 2. They received FC once a day in doses from 0.05 to 0.1 mg. Under such therapy, growth velocity was normal starting from the age of 2.5 years with an overall average of +0.2 SD in patient 1 and -0.1 SD in patient 2, androstenedione levels were always within normal age range. Similarly, BMI and blood pressure were always normal, no acne and no hirsutism ever appeared. In conclusion, two siblings with the same genetic form of 21-hydroxylase deficiency and excellent adherence to medication showed different growth and menstrual cycle patterns, rather related to constitutional factors than to underlying CAH. In addition, the second patient represents an example of successful in utero glucocorticoid treatment to prevent virilization of the external genitalia

Digital Transformation and IT: Current State of Research

Information Systems (IS) have never been more important as digital technologies are essential for business model innovation by developing new digital products and services. Digital transformation not only affects business, but also IT. While digital transformation and digital technologies are well established research areas, the implications of digital transformation on IT are rarely in focus. Taking this topic as a reference, the paper contributes to general IS research by assessing to which extent digital innovation is already subject to mainstream IS research. A bibliometric study analyzing all 2,833 articles published in the AIS Senior Scholars’ \u27basket\u27 of eight leading IS journals between 2007 and 2016 reveals that a mere 0.2% address the impact of digital transformation on IT while 2.3% cover topics of digital transformation, innovation, or digital technologies. In contrast to previous work, this study finds that digital innovation research is already present in primarily high-ranked IS journals

AGILE CONTRACTS: LEARNINGS FROM AN AUTONOMOUS DRIVING SOURCING PROJECT

New digital services and products rely heavily on digital technologies and need to be deployed in an ever-shorter timeframe in response to rapidly changing market demands. To address this challenge, more and more companies are applying agile practices to increase speed and flexibility. In consequence, companies review their sourcing strategies to shorten the duration of tenders for large-scale IT projects and to increase flexibility in contracting of IT services to cope with the anticipated consequences of digital transformation. This study aims at revealing how agile practices could help to reduce time-to-market and to increase contract flexibility. As the automotive industry is especially affected by the adoption of new digital technologies, this revelatory case study shows how a German car manufacturer increased agility in sourcing and contracting of an autonomous driving development platform. Agile practices turned out to be essential in dealing with technological novelty and hurdles, regulatory uncertainty, and frequently changing requirements. We contribute to the extant knowledge by providing practical recommendations on how to increase agility in sourcing and contracting of large-scale IT projects

Implementing Scaled-Agile Frameworks at Non-Digital Born Companies - A Multiple Case Study

For traditional enterprises to harness the advantages of organizational agility, scaled-agile frameworks seem to be more appropriate to adopt agile practices at large scale. However, the adoption of agile practices often creates trade-offs between the implementation of an ideal theoretical framework and company-specific necessities. While extant research has covered the implications and challenges when adopting agile structures, our research focuses on the how and why of such trade-offs using Socio-Technical Systems Theory. Drawing on the results of an exploratory multiple case study, we reveal that companies either choose a top-down or bottom-up approach for implementation. While the first often is triggered by the need to increase customer centricity, the latter is mostly triggered by the need to increase the number of releases. Moreover, we found that the selected implementation approach has significant impact on the key design parameters for and the content of the implementation of scaled-agile frameworks

Kibble-Zurek scaling of the one-dimensional Bose-Hubbard model at finite temperatures

We use tensor network methods - Matrix Product States, Tree Tensor Networks, and Locally Purified Tensor Networks - to simulate the one dimensional Bose-Hubbard model for zero and finite temperatures in experimentally accessible regimes. We first explore the effect of thermal fluctuations on the system ground state by characterizing its Mott and superfluid features. Then, we study the behavior of the out-of-equilibrium dynamics induced by quenches of the hopping parameter. We confirm a Kibble-Zurek scaling for zero temperature and characterize the finite temperature behavior, which we explain by means of a simple argument.Comment: 13 pages, 12 figure

Sustainability of Nutraceuticals and Functional Foods

Sustainability challenges and issues in nutraceuticals and functional foods arena have influenced both consumers and the industrial sector. Though the present day can be termed as an era of nutraceuticals and functional foods, the knowledge on sustainability among the people involved is limited in the pharma‐food industry. In this chapter, we provide a general overview of this subject, followed by discussion on the four pillars of sustainability and how these relate to the agricultural system, food safety and food security. Examples of nutraceuticals products, health benefits incurred, consumer trends and food choices as well as market values are all examined

“Das süße Gift des Pazifismus”? Die westdeutschen Katholiken und das Ringen um ein neues Friedensdenken, 1979-1983

The discussions and protests on peace in the early 1980s were not without influence on the attitudes of West German Catholics on the topic. Since 1945 it was the first time that a significant amount of Catholics in the Federal Republic dealt with issues of »war« and »peace«. Against this background, the article will focus on different Catholic actors and their positioning within the general discussion on peace of West German society as such. It will analyse if and to which extent Catholic actors developed their own genuine concept of peace. As a main result my research proofs that dimension and bias of Catholic commitment for peace were highly depended on functions and purposes of the various actors. For instance, the progressive initiative »Kirche von unten« sought for a broader support of its general aims by building a coalition with non-Catholic actors. On the contrary, groups deeper rooted in Catholic traditions, such as the Catholic peace movement »Pax Christi«, aimed more strongly for discussion on the issues within the Catholic community. Eventually, the majority of West German Catholics kept on supporting the conservative government’s traditional security policy