Edge theories in Projected Entangled Pair State models

We study the edge physics of gapped quantum systems in the framework of Projected Entangled Pair State (PEPS) models. We show that the effective low-energy model for any region acts on the entanglement degrees of freedom at the boundary, corresponding to physical excitations located at the edge. This allows us to determine the edge Hamiltonian in the vicinity of PEPS models, and we demonstrate that by choosing the appropriate bulk perturbation, the edge Hamiltonian can exhibit a rich phase diagram and phase transitions. While for models in the trivial phase any Hamiltonian can be realized at the edge, we show that for topological models, the edge Hamiltonian is constrained by the topological order in the bulk which can e.g. protect a ferromagnetic Ising chain at the edge against spontaneous symmetry breaking.Comment: 5 pages, 4 figure

Transfer Matrices and Excitations with Matrix Product States

We investigate the relation between static correlation functions in the ground state of local quantum many-body Hamiltonians and the dispersion relations of the corresponding low energy excitations using the formalism of tensor network states. In particular, we show that the Matrix Product State Transfer Matrix (MPS-TM) - a central object in the computation of static correlation functions - provides important information about the location and magnitude of the minima of the low energy dispersion relation(s) and present supporting numerical data for one-dimensional lattice and continuum models as well as two-dimensional lattice models on a cylinder. We elaborate on the peculiar structure of the MPS-TM's eigenspectrum and give several arguments for the close relation between the structure of the low energy spectrum of the system and the form of static correlation functions. Finally, we discuss how the MPS-TM connects to the exact Quantum Transfer Matrix (QTM) of the model at zero temperature. We present a renormalization group argument for obtaining finite bond dimension approximations of MPS, which allows to reinterpret variational MPS techniques (such as the Density Matrix Renormalization Group) as an application of Wilson's Numerical Renormalization Group along the virtual (imaginary time) dimension of the system.Comment: 39 pages (+8 pages appendix), 14 figure

Extracts of Tagetes minuta L. front of bacteria regarding bovine mastites.

Bovine mastitis is a problem in the context of animal health. However medicinal plants are a management strategy in agroecological production systems. In this context, the plant Tagetes minuta L. plays a leading role, due to its recognition in the popular pharmacopeia. Thus, the objective of this work was to assess the effect of hydroalcoholic extracts of T. minuta from different collection sites compared to ten bacteria related to bovine mastitis. The antimicrobial evaluation was done through the microdilution technique in syrup, in 96 well microplates in triplicate, for the determination of Minimal Bacterial Concentration (MBC) (%). In the microplates, the extracts of T. minuta and the inoculums of the bacteria were placed in addition to the growth control of the bacteria and the control of the extracts, which were incubated for 72 hours at 37°C in an oven. After this time, aliquots of 5?L of each orifice were transferred to plates containing 5% equine defibrinated blood agar and maintained in incubation for 24 hours at the same previous temperature. With this, the growth readings were performed, with the subsequent interpretation of the results by the geometric mean of the MBC (%). The results indicate that there is a difference in sensitivity to microorganisms by the extracts as a function of the collection sites and both present antimicrobial action

Universal quantum gates based on both geometric and dynamic phases in quantum dots

A large-scalable quantum computer model, whose qubits are represented by the subspace subtended by the ground state and the single exciton state on semiconductor quantum dots, is proposed. A universal set of quantum gates in this system may be achieved by a mixed approach, composed of dynamic evolution and nonadibatic geometric phase.Comment: 4 pages, to appear in Chin. Phys. Let

Physical Multimorbidity and Sarcopenia among Adults Aged ≥65 Years in Low- and Middle-Income Countries

Introduction: Physical multimorbidity is plausibly linked to sarcopenia. However, to date, only a few studies exist on this topic, and none have examined this association in low- and middle-income countries (LMICs). Thus, we aimed to investigate the association between multimorbidity and sarcopenia in a sample of older adults from six LMICs (China, Ghana, India, Mexico, Russia, South Africa). Methods: Cross-sectional, community-based data from the WHO Study on Global Ageing and Adult Health (SAGE) were analysed. Sarcopenia was defined as having low skeletal muscle mass (SMM) and weak handgrip strength, while severe sarcopenia was defined as having low SMM, weak handgrip strength, and slow gait speed. A total of 11 physical chronic conditions were assessed and multimorbidity referred to ≥2 chronic conditions. Multivariable logistic regression analysis was conducted. Results: Data on 14,585 adults aged ≥65 years were analysed (mean age 72.6 years, SD 11.5 years; 53.7% females). Adjusted estimates showed that compared to no chronic physical conditions, ≥2 conditions are significantly associated with 1.49 (95% CI = 1.02–2.19) and 2.52 (95% CI = 1.53–4.15) times higher odds for sarcopenia and severe sarcopenia, respectively. Conclusions: In this large sample of older adults from LMICs, physical multimorbidity was significantly associated with sarcopenia and severe sarcopenia. Our study results tentatively suggest that targeting those with multimorbidity may aid in the prevention of sarcopenia, pending future longitudinal research

One-shot entanglement generation over long distances in noisy quantum networks

We consider the problem of creating a long-distance entangled state between two stations of a network, where neighboring nodes are connected by noisy quantum channels. We show that any two stations can share an entangled pair if the effective probability for the quantum errors is below a certain threshold, which is achieved by using local redundant encoding to preserve the global phase and network-based correction for the bit-flip errors. In contrast to the convensional quantum repeater schemes we are not limited by the memory coherence time, because all quantum operations only use one-way classical communication and can be done in one shot. Meanwhile, the overhead of local resources only increases logarithmically with the size of the network, making our proposal favorable to practical applications of long-distance quantum communication.Comment: revtex4, 6 pages, 5 figures (.eps

HITRAP: A facility at GSI for highly charged ions

An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fuer Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.Comment: 8 pages, 11 figure