High-accuracy optical clock based on the octupole transition in 171Yb+

We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition 2S1/2(F=0) -> F7/2(F=3) in a single trapped 171Yb+ ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f136s2 configuration of the upper state. The electric quadrupole moment of the 2F7/2 state is measured as -0.041(5) e(a0)^2, where e is the elementary charge and a0 the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe light induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1x10^(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz.Comment: 5 pages, 4 figure

Strategic Market Games with a Finite Horizon and Incomplete.

We study a strategic market game associated to an intertemporal economy with a finite horizon and incomplete markets. We demonstrate that generically, for any finite number of players, every sequentially strictly individually rational and default-free stream of allocations can be approximated by a full subgame-perfect equilibrium. As a consequence, imperfect competition may Pareto-dominate perfect competition when markets are incomplete. Moreover — and this contrasts with the main message conveyed by the market games literature — there exists a large open set of initial endowments for which full subgame-perfect equilibria do not converge to η- efficient allocations when the number of players tends to infinity. Finally, strategic speculative bubbles may survive at full subgame-perfect equilibria.Market Games, Folk Theorem, Incomplete Markets, Bubbles.

Economics of Literary Translation. A Simple Theory and Evidence

Books are an important factor of cultural transmission, but need, in most cases, to be translated. According to some authors, this may lead to a form of cultural domination of English. The population speaking English as a first language is, with the exception of Mandarin, the largest in the world. It is therefore not surprising that English produces more fiction (and much more scientific literature, as scientists from all countries write in English with increasing frequency) than any other language. We develop a theoretical model of translation, which is estimated on the basis of UNESCO translation data. We show that translations from English are dominated by translations from other languages, including Scandinavian ones and French.Languages, Translations, Cultural and Linguistic Distances

Equivalence of the sine-Gordon and massive Thirring models at finite temperature

Using the path-integral approach, the quantum massive Thirring and sine-Gordon models are proven to be equivalent at finite temperature. This result is an extension of Coleman's proof of the equivalence between both theories at zero temperature. The usual identifications among the parameters of these models also remain valid at $T \neq 0$.Comment: 9 pages, standard LaTe

Human papillomavirus vaccination coverage in Luxembourg : implications of lowering and restricting target age groups

Background: In Luxembourg, a national Human Papillomavirus (HPV) vaccination programme was introduced in 2008, targeting 12-17 year old girls offering a choice of bivalent or quadrivalent vaccine free of charge. In 2015, the programme was changed offering the bivalent vaccine only to 11-13 year old girls. The aim of this study was to evaluate the HPV vaccination coverage, to assess the impact of age target changes and compare vaccination coverage to other European countries. Methods: Anonymous HPV vaccination records consisting of individual vaccine doses obtained free of charge in pharmacies between 2008 and 2016 were extracted from the Luxembourgish Social Security database. Additional aggregate tables by nationality and municipality were analysed. Results: Of the target cohort of 39,610 girls born between 1991 and 2003 residing in Luxembourg, 24,550 (62.0%) subjects obtained at least one dose, 22,082 (55.7%) obtained at least two doses, and 17,197 (43.4%) obtained three doses of HPV vaccine. The mean age at first dose was 13.7 years during 200814 and 12.7 years in 2016 after the age target change. Coverage varied significantly by nationality (p < 0.0001): Portuguese (80%), former Yugoslays (74%), Luxembourgish (54%), Belgian (52%), German (47%), French (39%) and other, nationalities (51%). Coverage varied also by geographical region, with lower rates (<50%) noted in some Northern and Central areas of Luxembourg (range: 38% to 78%). Conclusion: Overall HPV vaccination coverage in Luxembourg is moderate and varied by nationality and region. The policy changes in 2015 did not have a substantial impact except lowering age at initiating vaccination. Options to improve coverage deserve further investigation

Are Remakes Doing as Well as Originals? A note.

This paper compares originals and remakes from the standpoint of artistic quality and financial return. It appears that on average remakes are of lower quality and have smaller financial returns than originals.

Economics of literary translation : A simple theory and evidence

Books are an important factor of cultural transmission, but need, in most cases, to be translated. According to some authors, this may lead to a form of cultural domination, in particular of English, on other languages. All these papers ignore that thepopulation speaking English as a first language is, with the exception of Mandarin, the largest in the world. It is therefore not surprising that English produces more fiction (and much more scientific literature, as scientists from all countries write more and more in English) than any other language. We develop a theoretical model of translation, which is estimated on the basis of UNESCO translation data. We show that translations from English are dominated by translations from other languages,including Scandinavian ones and French.languages, translations, cultural and linguistic distances

Atomic trajectory characterization in a fountain clock based on the spectrum of a hyperfine transition

We describe a new method to determine the position of the atomic cloud during its interaction with the microwave field in the cavity of a fountain clock. The positional information is extracted from the spectrum of the F=3,mF=0 to F=4,mF=-1 hyperfine transition, which shows a position dependent asymmetry when the magnetic C-field is tilted by a few degrees with respect to the cavity axis. Analysis of this spectral asymmetry provides the horizontal center-of-mass position for the ensemble of atoms contributing to frequency measurements. With an uncertainty on the order of 0.1 mm, the obtained information is useful for putting limits on the systematic uncertainty due to distributed cavity phase gradients. The validity of the new method is demonstrated through experimental evidence.Comment: 6 figures, submitted to PR