1,526,518 research outputs found
Integration of fiber coupled high-Q silicon nitride microdisks with atom chips
Micron scale silicon nitride (SiN_x) microdisk optical resonators are
demonstrated with Q = 3.6 x 10^6 and an effective mode volume of 15 (\lambda /
n)^3 at near visible wavelengths. A hydrofluoric acid wet etch provides
sensitive tuning of the microdisk resonances, and robust mounting of a fiber
taper provides efficient fiber optic coupling to the microdisks while allowing
unfettered optical access for laser cooling and trapping of atoms. Measurements
indicate that cesium adsorption on the SiN_x surfaces significantly red-detunes
the microdisk resonances. A technique for parallel integration of multiple (10)
microdisks with a single fiber taper is also demonstrated.Comment: Published vesion. Minor change
Integral foliated simplicial volume and ergodic decomposition
We establish an integration formula for integral foliated simplicial volume
along ergodic decompositions. This is analogous to the ergodic decomposition
formula for the cost of groups.Comment: 15 pages; v2: corrected the main proof and improved the exposition;
to appear in Annales Math\'ematiques Blaise Pasca
Silver mean conjectures for 15-d volumes and 14-d hyperareas of the separable two-qubit systems
Extensive numerical integration results lead us to conjecture that the silver
mean, that is, s = \sqrt{2}-1 = .414214 plays a fundamental role in certain
geometries (those given by monotone metrics) imposable on the 15-dimensional
convex set of two-qubit systems. For example, we hypothesize that the volume of
separable two-qubit states, as measured in terms of (four times) the minimal
monotone or Bures metric is s/3, and 10s in terms of (four times) the Kubo-Mori
monotone metric. Also, we conjecture, in terms of (four times) the Bures
metric, that that part of the 14-dimensional boundary of separable states
consisting generically of rank-four 4 x 4 density matrices has volume
(``hyperarea'') 55s/39 and that part composed of rank-three density matrices,
43s/39, so the total boundary hyperarea would be 98s/39. While the Bures
probability of separability (0.07334) dominates that (0.050339) based on the
Wigner-Yanase metric (and all other monotone metrics) for rank-four states, the
Wigner-Yanase (0.18228) strongly dominates the Bures (0.03982) for the
rank-three states.Comment: 30 pages, 6 tables, 17 figures; nine new figures and one new table in
new section VII.B pertaining to 14-dimensional hyperareas associated with
various monotone metric
Wheeler-DeWitt Quantization of Gravity Models of Unified Dark Energy and Dark Matter
First, we describe the construction of a new type of gravity-matter models
based on the formalism of non-Riemannian space-time volume forms - alternative
generally covariant integration measure densities (volume elements) defined in
terms of auxiliary antisymmetric tensor gauge fields. Here gravity couples in a
non-conventional way to two distinct scalar fields providing a unified
Lagrangian action principle description of: (i) the evolution of both "early"
and "late" Universe - by the "inflaton" scalar field; (ii) dark energy and dark
matter as a unified manifestation of a single material entity - the "darkon"
scalar field. A physically very interesting phenomenon occurs when including in
addition interactions with the electro-weak model bosonic sector - we obtain a
gravity-assisted dynamical generation of electro-weak spontaneous gauge
symmetry breaking in the post-inflationary "late" Universe, while the
Higgs-like scalar remains massless in the "early" Universe. Next, we proceed to
the Wheeler-DeWitt minisuperspace quantization of the above models. The
"darkon" field plays here the role of cosmological "time". In particular, we
show the absence of cosmological space-time singularities.Comment: 15 pages, to be published in the Proceedings of QTS10 - 10th
International Symposium "Quantum Theory and Symmetries" (Varna, 2017),
Springer Proceedings in Mathematics and Statistics, V. Dobrev (ed.). arXiv
admin note: text overlap with arXiv:1609.0691
Lessons Learned During CMS Tracker End Cap Construction
With more than 15 000 silicon strip modules and a silicon area of about 200 square metres, the CMS silicon strip tracker will be the largest silicon strip tracker ever built. More than half of the volume is occupied by the two end caps, which comprise about 42 % of the silicon strip modules. Construction of the end caps is far advanced. In this article the experience from module production, integration of medium-sized substructures, so-called petals, and from the integration of the end caps themselves is summarized
Social Preferences in Small‐Scale Societies
This volume reports on a cross‐cultural investigation of social preferences in 15 small‐scale, non‐Western societies. Participants from all 15 groups played the ultimatum game with members of their own culture; subjects from a subset also played dictator and voluntary contribution to public goods games. The bulk of the book (Chapters 4 through 14) consists of reports by the field workers (mostly anthropologists). Each chapter includes ethnographic information, a description of how members of the group make their living, details on the experimental protocols and results, and some discussion. Although none of the results are consistent with the predictions of the standard rational choice model (as has been true in earlier work), group average offers and rejection frequencies in these experiments display more variation than has been observed in experiments using university students from developed Westernized societies. The editors report that little of this variation can be accounted for by individual economic or demographic variables, such as gender, age, education, or wealth. On the other hand, group dummies account for quite a lot, and social preferences seem to be stronger in groups experiencing greater market integration or whose economic mode offers greater opportunities for gains from cooperative enterprise
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