Comment on "Phase Diagram of an Asymmetric Spin Ladder."

A comment to the paper by S. Chen, H. B\"uttner, and J. Voit, [Phys. Rev. Lett. {\bf 87}, 087205 (2001)].Comment: 1 page, 1 figure, to appear in Physical Review Letter

Anticipations effects in endogeneous probability-migration models

We analyze a probability-migration model based on the threshold of average human capital as in H.-J. Chen [1]. The difficult and interesting case is the one where the probability of migration is dependent on current average human capital (the anticipative case). Here, indeterminacy occurs, and one has to study a lot of subcases. In the present article we deeply study new interesting cases and we give a global answer.Human capital, Education, Migration, Indeterminacy, Economic growth, Threshold human capital, Fixed point, Optimistic and pessimistic mechanisms, Conservative mechanism

Researchers Honored

News release announces that engineering researchers Dilip R. Ballal and Tzong H. Chen are recipients of the 1986 Wohlleben-Hochwalt Outstanding Professional Research Award

Revisit cosmic ray propagation by using 1^{1}H, 2^{2}H, 3^{3}He and 4^{4}He

The secondary-to-primary ratios are unique tools to investigate cosmic ray propagation mechanisms. In this work, we use the latest data of deuteron-to-helium~4 ratio and helium~3-to-helium~4 ratio measured by PAMELA combined with other Z$\leq$2 primary fluxes measured by PAMELA and Voyager-1, to constrain the cosmic ray acceleration and propagation models. The analysis is performed by interfacing statistical tools with the GALPROP propagation package. To better fit both the modulated and unmodulated low energy cosmic ray data, we find that a time-, charge- and rigidity-dependent solar modulation model is better than the force-field approximation. Among all the studied cosmic ray propagation models, the diffusion-reacceleration-convection model is strongly supported by the derived Bayesian evidence. The robustness of the estimated diffusion slope $\delta$ is cross-checked by another low-mass secondary-to-primary ratio, i.e. the antiproton-to-proton ratio. It is shown that the diffusion-reacceleration-convection model can reconcile well with the high energy antiproton-to-proton ratio. This indicates that the estimated value of $\delta$ is reliable. The well constraint $\delta$ from the `best' model is found to be close to 1/3, inferring a Kolmogorov-type interstellar magnetic turbulence.Comment: Accepted by Physics Letters

Nucleon spin decomposition and differential geometry

In the last few years, the so-called Chen et al. approach of the nucleon spin decomposition has been widely discussed and elaborated on. In this letter we propose a genuine differential geometric understanding of this approach. We mainly highligth its relation to the "dressing field method" we advocated in [C. Fournel, J. Fran\c{c}ois, S. Lazzarini, T. Masson, Int. J. Geom. Methods Mod. Phys. 11, 1450016 (2014)]. We are led to the conclusion that the claimed gauge-invariance of the Chen et al. decomposition is actually unreal.Comment: 9 pages. v3: minor corrections in the text, addition of a new referenc

Book Review: The Moral Tradition of American Constitutionalism: A Theological Interpretation. by H. Jefferson Powell.

Book review: The Moral Tradition of American Constitutionalism: A Theological Interpretation. By H. Jefferson Powell. Durham: Duke University Press. 1993. Pp. ix, 296. Reviewed by: Jim Chen