We develop a systematic approach for constructing symmetry-based indicators of a topological classification for superconducting systems. The topological invariants constructed in this work form a ...complete set of symmetry-based indicators that can be computed from knowledge of the Bogoliubov–de Gennes Hamiltonian on high-symmetry points in the Brillouin zone. After excluding topological invariants corresponding to the phases without boundary signatures, we arrive at a natural generalization of symmetry-based indicators H. C. Po, A. Vishwanath, and H. Watanabe, Nat. Commun. 8, 50 (2017) to Hamiltonians of Bogoliubov–de Gennes type.
We study a link between the ground-state topology and the topology of the lattice via the presence of anomalous states at disclinations -- topological lattice defects that violate a rotation symmetry ...only locally.
We first show the existence of anomalous disclination states, such as Majorana zero-modes or helical electronic states, in second-order topological phases by means of Volterra processes.
Using the framework of topological crystals to construct d-dimensional crystalline topological phases with rotation and translation symmetry, we then identify all contributions to (d-2)-dimensional anomalous disclination states from weak and first-order topological phases.
We perform this procedure for all Cartan symmetry classes of topological insulators and superconductors in two and three dimensions and determine whether the correspondence between bulk topology, boundary signatures, and disclination anomaly is unique.
On an unusually cold January night in 1943, Martha James was murdered on a train in rural Oregon, near the Willamette Valley town of Albany. She was White, Southern, and newly-married to a Navy ...pilot. Despite inconsistent and contradictory eyewitness accounts, a young Black cook by the name of Robert Folkes, a trainman from South Central Los Angeles, was charged with the crime. The ensuing investigation and sensational murder trial captured national attention during a period of intense wartime fervor and extensive Black domestic migration. Folkes’ trial and controversial conviction—resulting in his execution by the state of Oregon—reshaped how Oregonians and others in the West thought about race, class, and privilege.
In this deeply researched and detailed account, Geier explores how race, gender, and class affected the attitudes of local town-folk, law officers, and courtroom jurors toward Black trainmen on the West Coast, at a time when militarization skewed perceptions of virtue, status, and authority. He delves into the working conditions and experiences of unionized Black trainmen in their “home and away” lives in Los Angeles and Portland, while illuminating the different ways that they, and other residents of Oregon and southern California, responded to news of “Oregon’s murdered war bride.” Reporters, civil rights activists, and curiosity seekers transformed the trial and appeals process into a public melodrama.
The investigation, trial, and conviction of Robert Folkes galvanized civil rights activists, labor organizers, and community leaders into challenging the flawed judicial process and ultimately the death penalty in Oregon, serving as a catalyst for civil rights activism that bridged rural and urban divides. The Color of Night will appeal to “true crime” aficionados, and to anyone interested in the history of race and labor relations, working conditions, community priorities, and attitudes toward the death penalty in the first half of the 20th century.
Second-order topological insulators and superconductors have a gapped excitation spectrum in bulk and along boundaries, but protected zero modes at corners of a two-dimensional crystal or protected ...gapless modes at hinges of a three-dimensional crystal. A second-order topological phase can be induced by the presence of a bulk crystalline symmetry. Building on Shiozaki and Sato's complete classification of bulk crystalline phases with an order-two crystalline symmetry Phys. Rev. B 90, 165114 (2014), such as mirror reflection, twofold rotation, or inversion symmetry, we classify all corresponding second-order topological insulators and superconductors. The classification also includes antiunitary symmetries and antisymmetries.
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