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

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

Corrigendum: COVID-19 Confinement and Health Risk Behaviors in Spain

In the original article, the reference for Chen et al. (2009) was incorrectly written as “Chen, P., Mao, L., Nassis, G. P., Harmer, P., Ainsworth, B. E., and Li, F. (2009). Wuhan coronavirus (2019-nCoV): the need to maintain regular physical activity while taking precautions. J. Sport Health Sci. 9, 103–104. doi: 10.1016/j.jshs.2020.02.001”. It should be “Chen, P., Mao, L., Nassis, G. P., Harmer, P., Ainsworth, B. E., and Li, F. (2020). Coronavirus disease (COVID-19): The need to maintain regular physical activity while taking precautions. J. Sport Health Sci. 9, 103–104. doi: 10.1016/j.jshs.2020.02.001”. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated