Thermal conductance as a probe of the non-local order parameter for a topological superconductor with gauge fluctuations

We investigate the effect of quantum phase slips on a helical quantum wire coupled to a superconductor by proximity. The effective low-energy description of the wire is that of a Majorana chain minimally coupled to a dynamical $\mathbb{Z}_2$ gauge field. Hence the wire emulates a matter-coupled gauge theory, with fermion parity playing the role of the gauged global symmetry. Quantum phase slips lift the ground state degeneracy associated with unpaired Majorana edge modes at the ends of the chain, a change that can be understood as a transition between the confined and the Higgs-mechanism regimes of the gauge theory. We identify the quantization of thermal conductance at the transition as a robust experimental feature separating the two regimes. We explain this result by establishing a relation between thermal conductance and the Fredenhagen-Marcu string order-parameter for confinement in gauge theories. Our work indicates that thermal transport could serve as a measure of non-local order parameters for emergent or simulated topological quantum order.Comment: 5 pages, 2 figures; v2: different introduction, added references, updated figure 2; published version to appear in PR

Eighty years of service: A history of the Presbyterian Theological Seminary at Omaha, Nebraska

The purpose of this study has been to trace the history of the Presbyterian Theological Seminary at Omaha, The major resources used have been the minutes of organizational bodies related to the school catalogues, and the seminary magazine, The Seminary Record.In depth study of these materials leaves this student with a deep respect and admiration for the men who founded the institution and those who continue to give of their time and talents that Omaha Seminary might serve the Presbyterian Church. The quantity of the records available made it necessary to eliminate many details, which vividly portray the dedication of these men