Effects of large induced superconducting gap on semiconductor Majorana nanowires

With the recent achievement of extremely high-quality epitaxial interfaces between InAs nanowires and superconducting Al shells with strong superconductor-semiconductor tunnel coupling, a new regime of proximity-induced superconductivity in semiconductors can be explored where the induced gap may be similar in value to the bulk Al gap (large gap) with negligible subgap conductance (hard gap). We propose several experimentally relevant consequences of this large-gap strong-coupling regime for tunneling experiments, and we comment on the prospects of this regime for topological superconductivity. In particular, we show that the advantages of having a strong spin-orbit coupling and a large spin g-factor in the semiconductor nanowire may both be compromised in this strongly coupled limit, and somewhat weaker interface tunneling may be necessary for achieving optimal proximity superconductivity in the semiconductor nanowire. We derive a minimal, generic theory for the strong-coupling hard-gap regime obtaining good qualitative agreement with the experiment and pointing out future directions for further progress toward Majorana nanowires in hybrid semiconductor-superconductor structures.Comment: 8 pages, 5 figures; published versio

[Review of] Sebastian Clarke, Jah Music: The Evolution of the Popular Jamaican Song

In Jah Music, Sebastian Clarke has offered a wealth of information on Jamaican popular music especially to this reader who, although a musician and ethnomusicologist, knew very little about the popular music of Jamaica previously. Clarke has provided material on the roots and history of the music: the birth and development of Rastafarianism, then the evolutionary development of Jamaican music, and its three most powerful exponents, Bob Marley, Peter Tosh, and Bunny Wailer. There is also a chapter on the spoken word, which is the key to all African-derived music. Whether articulated by voice or by another instrument, the word is the essence of all musics which have sprung up in the Western hemisphere with roots in Africa. The book has a very detailed index, directory of artists and discography, and is scrupulously footnoted to support the author\u27s conclusions

Bose Hubbard Models with Synthetic Spin-Orbit Coupling: Mott Insulators, Spin Textures and Superfluidity

Motivated by the experimental realization of synthetic spin-orbit coupling for ultracold atoms, we investigate the phase diagram of the Bose Hubbard model in a non-abelian gauge field in two dimensions. Using a strong coupling expansion in the combined presence of spin-orbit coupling and tunable interactions, we find a variety of interesting magnetic Hamiltonians in the Mott insulator (MI), which support magnetic textures such as spin spirals and vortex and Skyrmion crystals. An inhomogeneous mean field treatment shows that the superfluid (SF) phases inherit these exotic magnetic orders from the MI and display, in addition, unusual modulated current patterns. We present a slave boson theory which gives insight into such intertwined spin-charge orders in the SF, and discuss signatures of these orders in Bragg scattering, in situ microscopy, and dynamic quench experiments.Comment: 4 pages + references + supplementary inf