827 research outputs found
Spin waves in the (0,pi) and (0,pi,pi) ordered SDW states of the t-t' Hubbard model: Application to doped iron pnictides
Spin waves in (0,pi) and (0,pi,pi) ordered spin-density-wave (SDW) states of
the t-t' Hubbard model are investigated at finite doping. In the presence of
small t', these composite ferro-antiferromagnetic (F-AF) states are found to be
strongly stabilized at finite hole doping due to enhanced carrier-induced
ferromagnetic spin couplings as in metallic ferromagnets. Anisotropic spin-wave
velocities, spin-wave energy scale of around 200meV, reduced magnetic moment,
and rapid suppression of magnetic order with electron doping x (corresponding
to F substitution of O atoms in La O_{1-x} F_x Fe As or Ni substitution of Fe
atoms in Ba Fe_{2-x} Ni_x As_2) obtained in this model are in agreement with
observed magnetic properties of doped iron pnictides.Comment: 13 pages, 3 figure
Frustrated multiband superconductivity
We show that a clean multiband superconductor may display one or several
phase transitions with increasing temperature from or to frustrated
configurations of the relative phases of the superconducting order parameters.
These transitions may occur when more than two bands are involved in the
formation of the superconducting phase and when the number of repulsive
interband interactions is odd. These transitions are signalled by slope changes
in the temperature dependence of the superconducting gaps.Comment: 5 pages, 3 figure
De las clases de gestión en la FAMURP a la acción: El plan estratégico 2017-2021 de la sociedad científica médico estudiantil peruana
Se conoce que la participación en Sociedades Científicas de Estudiantes de Medicina (SOCIEMS) permite que los estudiantes de medicina humana adscritos a éstas adquieran competencias principalmente en el ámbito de la investigación científica, sin embargo un aspecto adicional es la adquisición en paralelo de habilidades en gestión1 . La mayoría de facultades de medicina de nuestro país incorporan en sus mallas curriculares cursos en gestión en salud dirigidos a estudiantes de medicina de los últimos años; a esta realidad no es ajena la FAMURP: Facultad de Medicina Humana de la Universidad Ricardo Palma, en la cual dicho curso es impartido en el Ciclo XI del Sexto Año de la carrera2 . En dicho curso se brindan los conocimientos, herramientas y metodologías para desarrollar competencias que faciliten la participación en gestión efectiva y eficiente de los establecimientos de salud y servicios basados en la atención primaria de salud .
DOI:https://doi.org/10.25176/RFMH.v17.n1.75
Theory of Andreev reflection in a two-orbital model of iron-pnictide superconductors
A recently developed theory for the problem of Andreev reflection between a
normal metal (N) and a multiband superconductor (MBS) assumes that the incident
wave from the normal metal is coherently transmitted through several bands
inside the superconductor. Such splitting of the probability amplitude into
several channels is the analogue of a quantum waveguide. Thus, the appropriate
matching conditions for the wave function at the N/MBS interface are derived
from an extension of quantum waveguide theory. Interference effects between the
transmitted waves inside the superconductor manifest themselves in the
conductance. We provide results for a FeAs superconductor, in the framework of
a recently proposed effective two-band model and two recently proposed gap
symmetries: in the sign-reversed s-wave () scenario
resonant transmission through surface Andreev bound states (ABS) at nonzero
energy is found as well as destructive interference effects that produce zeros
in the conductance; in the extended s-wave ()
scenario no ABS at finite energy are found.Comment: 4 pages, 5 figure
A complete characterization of plateaued Boolean functions in terms of their Cayley graphs
In this paper we find a complete characterization of plateaued Boolean
functions in terms of the associated Cayley graphs. Precisely, we show that a
Boolean function is -plateaued (of weight ) if and only
if the associated Cayley graph is a complete bipartite graph between the
support of and its complement (hence the graph is strongly regular of
parameters ). Moreover, a Boolean function is
-plateaued (of weight ) if and only if the associated
Cayley graph is strongly -walk-regular (and also strongly
-walk-regular, for all odd ) with some explicitly given
parameters.Comment: 7 pages, 1 figure, Proceedings of Africacrypt 201
WHAT SHOULD AI KNOW? INFORMATION DISCLOSURE IN HUMAN-AI COLLABORATION
AI-assisted Design Thinking shows great potential for supporting collaborative creative work. To foster creative thinking processes within teams with individualized suggestions, AI has to rely on data provided by the teams. As a prerequisite, team members need to weigh their disclosure preferences against the potential benefits of AI when disclosing information. To shed light on these decisions, we identify relevant information such as emotional states or discussion arguments that design thinking teams could provide to AI to enjoy the benefits of its support. Using the privacy calculus as theoretical lens, we draft a research design to analyze user preferences for disclosing different information relevant to the service bundles that AI provides for respective information. We make explorative contributions to the body of knowledge in terms of AI use and its corresponding information disclosure. The findings are relevant for practice as they guide the design of AI that fosters information disclosure
Spin-1/2 particles moving on a 2D lattice with nearest-neighbor interactions can realize an autonomous quantum computer
What is the simplest Hamiltonian which can implement quantum computation
without requiring any control operations during the computation process? In a
previous paper we have constructed a 10-local finite-range interaction among
qubits on a 2D lattice having this property. Here we show that
pair-interactions among qutrits on a 2D lattice are sufficient, too, and can
also implement an ergodic computer where the result can be read out from the
time average state after some post-selection with high success probability.
Two of the 3 qutrit states are given by the two levels of a spin-1/2 particle
located at a specific lattice site, the third state is its absence. Usual
hopping terms together with an attractive force among adjacent particles induce
a coupled quantum walk where the particle spins are subjected to spatially
inhomogeneous interactions implementing holonomic quantum computing. The
holonomic method ensures that the implemented circuit does not depend on the
time needed for the walk.
Even though the implementation of the required type of spin-spin interactions
is currently unclear, the model shows that quite simple Hamiltonians are
powerful enough to allow for universal quantum computing in a closed physical
system.Comment: More detailed explanations including description of a programmable
version. 44 pages, 12 figures, latex. To appear in PR
Life history parameters in acellular extrinsic fiber cementum microstructure
Life-history parameters such as pregnancies, skeletal trauma, and renal disease have previously been identified from hypomineralized growth layers (incremental lines) of acellular extrinsic fiber cementum (AEFC). The precise periodicity of these growth layers remains vaguely approximated, so causal life-history explanations using tooth cementum cannot yet be rigorously calculated or tested. On the other hand, we show how life history parameters in AEFC can be identified by two contrasting elemental detection methods. Based on our results we reject the possibility of accurate estimation of pregnancies and other life history parameters from cementum using scanning electron microscopy alone. Here, we propose a new methodological approach for cementum research, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), to measure degree and distribution of mineralization of cementum growth layers. Our results show that Tof-SIMS can significantly increase our knowledge of cementum composition and is therefore a powerful new tool for life history researchers
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