Entanglement renormalization for disordered systems

We propose a tensor network method for investigating strongly disordered systems that is based on an adaptation of entanglement renormalization [G. Vidal, Phys. Rev. Lett. 99, 220405 (2007)]. This method makes use of the strong disorder renormalization group to determine the order in which lattice sites are coarse-grained, which sets the overall structure of the corresponding tensor network ansatz, before optimization using variational energy minimization. Benchmark results from the disordered XXZ model demonstrates that this approach accurately captures ground state entanglement in disordered systems, even at long distances. This approach leads to a new class of efficiently contractible tensor network ansatz for 1D systems, which may be understood as a generalization of the multi-scale entanglement renormalization ansatz for disordered systems.Comment: 14 pages, 21 figure

Using entanglement to discern phases in the disordered one-dimensional Bose-Hubbard model

We perform a matrix product state based density matrix renormalisation group analysis of the phases for the disordered one-dimensional Bose-Hubbard model. For particle densities N/L = 1, 1/2 and 2 we show that it is possible to obtain a full phase diagram using only the entanglement properties, which come "for free" when performing an update. We confirm the presence of Mott insulating, superfluid and Bose glass phases when N/L = 1 and 1/2 (without the Mott insulator) as found in previous studies. For the N/L = 2 system we find a double lobed superfluid phase with possible reentrance.Comment: 6 pages, 4 figure

Leaf-to-leaf distances and their moments in finite and infinite m-ary tree graphs

We study the leaf-to-leaf distances on full and complete m-ary graphs using a recursive approach. In our formulation, leaves are ordered along a line. We find explicit analytical formulae for the sum of all paths for arbitrary leaf-to-leaf distance r as well as the average path lengths and the moments thereof. We show that the resulting explicit expressions can be recast in terms of Hurwitz-Lerch transcendants. Results for periodic trees are also given. For incomplete random binary trees, we provide first results by numerical techniques; we find a rapid drop of leaf-to-leaf distances for large r.Comment: 10 pages, 7 figure

Implementation of Safe Patient Toileting to Decrease Patient Falls on Medical-Surgical Unit

BACKGROUND: Patient falls are a serious safety concern in the hospital setting throughout the country. Falls are one of the most challenging patient safety events to prevent, as there are many contributing factors with toileting activities producing the highest incidence. Fall prevention bundles are used to minimize and reduce these such events although multifaceted. The project was conducted with an academic medical center on an acute inpatient medical-surgical unit primarily housing burn wound patients. Nursing leaders and front-line nursing staff participated. METHODS: Literature review to determine the gap in knowledge of interventions to prevent acute inpatient falls was completed. Concepts from purposeful rounding were used to identify a single intervention surrounding safe toileting activities. Staff actively self-reported via audit tool supervised patient toileting activities. Leadership support to develop increased engagement and satisfaction with the intervention was present. INTERVENTION: Purposeful toileting rounds utilizing acquired knowledge and skills to encourage patient’s participation in safe patient toileting activities. A daily shift self-reporting nursing staff auditing tool was deployed and utilized to track staff participation in supervised toileting bringing awareness to safe patient toileting. Lippitt’s and Lewin’s change theories were used to drive change with in the nursing unit and staff adoption of this workflow. RESULTS: The post intervention staff survey demonstrated staff engagement and improvement in supervised safe toileting patient activities. Staff results showed 23% overall improvement in satisfaction with time spent with patients, a 24% improvement in not feeling satisfied with unsupervised patient toileting, 31% combined positive satisfaction with providing privacy with toileting and 62% combined rating for satisfaction with safe toileting activities on the unit. Nurse pre- survey satisfaction scores of very dissatisfied were eliminated in the appropriate questions and increased in the one question regarding leaving patients unsupervised. The primary goal to reduce or eliminate falls was achieved with staff engagement. There were no patient falls during the project and continued without falls post implementation. CONCLUSION: The deployment of a single focused fall prevention intervention can successfully prevent patient falls with engagement and support of front-line nursing staff. Keywords: toileting, patient falls, fall preventio

An investigation of the leaching of copper tailings by means of potassium cyanide, precipitation of the dissolved copper by means of aluminum, with consequent regeneration of the cyanide consumed

One of the principal disadvantages attending the use of most of the usual solvents for Copper, such as Sulphuric Acid, Ferrous Chloride, etc., in the treatment of tailings products, is that the solvent is not regenerated upon precipitation by iron, and in fact is destroyed by the precipitant. This of course involves a dead loss of a definite portion of acid or other reagent, proportional to the amount of Copper dissolved. A solvent which would be regenerated upon precipitation is eminently desirable. At the same time, a carbonate gangue, or one of such a nature which will react with the solvent used, also entails an unavoidable loss. It is a well known fact that Aluminum forms no Cyanide compounds...With these results in mind, and knowing the strong tendency of Copper to go into a Cyanide solution, a series of tests were made with a view of determining the value of a process of Cyaniding Copper tailings, and precipitating the Copper with Aluminum --pages 1 -2

Some properties of Markov chains on the free group F2\mathbb F_2

Random walks cannot, in general, be pushed forward by quasi-isometries. Tame Markov chains were introduced as a `quasi-isometry invariant' are a generalization of random walks. In this paper, we construct several examples of tame Markov chains on the free group exhibiting `exotic' behaviour; one, where the drift is not well defined and one where the drift is well defined but the Central Limit Theorem does not hold. We show that this is not a failure of the notion of tame Markov chain, but rather that any quasi-isometry invariant theory that generalizes random walks will include examples without well-defined drift.Comment: 15 pages, 2 figures. Corrected some typos and added minor clarifications. To appear in Journal of Theoretical Probabilit

Northern Range Expansion and Invasion by the Common Carp, Cyprinus carpio, of the Churchill River System in Manitoba

Recent fisheries data from northern Manitoba indicates that the Common Carp (Cyprinus carpio) has extended the northern limit of its range. Additionally, it also appears that carp have invaded and established viable populations in the Manitoba portion of the Churchill River. Habitat degradation and altered flow regimes as result of hydroelectric development in northern Manitoba may have facilitated the expansion of carp in the region