1,949 research outputs found
In-gap impurity states as the hallmark of the Quantum Spin Hall phase
We study the different response to an impurity of the two topologically
different phases shown by a two dimensional insulator with time reversal
symmetry, namely, the Quantum Spin Hall and the normal phase. We consider the
case of graphene as a toy model that features the two phases driven,
respectively, by intrinsic spin-orbit coupling and inversion symmetry breaking.
We find that strictly normalizable in-gap impurity states only occur in the
Quantum Spin Hall phase and carry dissipationless current whose quirality is
determined by the spin and pseudospin of the residing electron. Our results
imply that topological order can be unveiled by local probes of defect states.Comment: 5 pages, 3 figure
Local control of entanglement in a spin chain
In a ferromagnetic spin chain, the control of the local effective magnetic
field allows to manipulate the static and dynamical properties of entanglement.
In particular, the propagation of quantum correlations can be driven to a great
extent so as to achieve an entanglement transfer on demand toward a selected
site
A methodology for full-system power modeling in heterogeneous data centers
The need for energy-awareness in current data centers has encouraged the use of power modeling to estimate their power consumption. However, existing models present noticeable limitations, which make them application-dependent, platform-dependent, inaccurate, or computationally complex. In this paper, we propose a platform-and application-agnostic methodology for full-system power modeling in heterogeneous data centers that overcomes those limitations. It derives a single model per platform, which works with high accuracy for heterogeneous applications with different patterns of resource usage and energy consumption, by systematically selecting a minimum set of resource usage indicators and extracting complex relations among them that capture the impact on energy consumption of all the resources in the system. We demonstrate our methodology by generating power models for heterogeneous platforms with very different power consumption profiles. Our validation experiments with real Cloud applications show that such models provide high accuracy (around 5% of average estimation error).This work is supported by the Spanish Ministry of Economy and Competitiveness under contract TIN2015-65316-P, by the Gener-
alitat de Catalunya under contract 2014-SGR-1051, and by the European Commission under FP7-SMARTCITIES-2013 contract 608679 (RenewIT) and FP7-ICT-2013-10 contracts 610874 (AS- CETiC) and 610456 (EuroServer).Peer ReviewedPostprint (author's final draft
Many-body effects on the capacitance of multilayers made from strongly correlated materials
Recent work by Kopp and Mannhart on novel electronic systems formed at oxide
interfaces has shown interesting effects on the capacitances of these devices.
We employ inhomogeneous dynamical mean-field theory to calculate the
capacitance of multilayered nanostructures. These multilayered nanostructures
are composed of semi-infinite metallic leads coupled via a strongly correlated
dielectric barrier region. The barrier region can be adjusted from a metallic
regime to a Mott insulator through adjusting the interaction strength. We
examine the effects of varying the barrier width, temperature, potential
difference, screening length, and chemical potential. We find that the
interaction strength has a relatively strong effect on the capacitance, while
the potential and temperature show weaker dependence.Comment: 19 pages, 7 figures, REVTe
Experiences of the White Gay Male: An Investigation of the Relationship between Factors of Being Gay, Heterosexism, and the Stress Response System
Prestige drives epistemic inequality in the diffusion of scientific ideas
The spread of ideas in the scientific community is often viewed as a
competition, in which good ideas spread further because of greater intrinsic
fitness, and publication venue and citation counts correlate with importance
and impact. However, relatively little is known about how structural factors
influence the spread of ideas, and specifically how where an idea originates
might influence how it spreads. Here, we investigate the role of faculty hiring
networks, which embody the set of researcher transitions from doctoral to
faculty institutions, in shaping the spread of ideas in computer science, and
the importance of where in the network an idea originates. We consider
comprehensive data on the hiring events of 5032 faculty at all 205
Ph.D.-granting departments of computer science in the U.S. and Canada, and on
the timing and titles of 200,476 associated publications. Analyzing five
popular research topics, we show empirically that faculty hiring can and does
facilitate the spread of ideas in science. Having established such a mechanism,
we then analyze its potential consequences using epidemic models to simulate
the generic spread of research ideas and quantify the impact of where an idea
originates on its longterm diffusion across the network. We find that research
from prestigious institutions spreads more quickly and completely than work of
similar quality originating from less prestigious institutions. Our analyses
establish the theoretical trade-offs between university prestige and the
quality of ideas necessary for efficient circulation. Our results establish
faculty hiring as an underlying mechanism that drives the persistent epistemic
advantage observed for elite institutions, and provide a theoretical lower
bound for the impact of structural inequality in shaping the spread of ideas in
science.Comment: 10 pages, 8 figures, 1 tabl
Work-In-Progress Paper: WebXR to support student wellbeing and anxiety
The COVID-19 pandemic social distancing measures had immense evidenced impact on student life in higher education affecting their mental health in many ways. In addition, remote working measures taken by Higher Education organizations to protect students and staff created an additional barrier for students seeking support at a stage they feel the most vulnerable. This paper presents a work-in-progress study that focuses on investigating ways of designing an online system for self-assessment symptoms of anxiety based on which available support is provided in a personalized and emotionally engaging manner. The project builds and compares three prototypes: a conventional web site; a VR immersive environment with a single virtual human playing the role of a student life advisor; and an immersive environment with more than one virtual humans interacting with the user aiming to study which system engages and assists vulnerable students more effectively, contributing to a better user experience. The paper presents that project motivations, its aims and objectives, the proposed research methodology and the expected contributions to knowledge
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