Decay widths in the massive Schwinger model

By a closer inspection of the massive Schwinger model within mass perturbation theory we find that, in addition to the $n$-boson bound states, a further type of hybrid bound states has to be included into the model. Further we explicitly compute the decay widths of the three-boson bound state and of the lightest hybrid bound state.Comment: 8 pages, Latex file, no figure

General bound-state structure of the massive Schwinger model

Within the Euclidean path integral and mass perturbation theory we derive, from the Dyson-Schwinger equations of the massive Schwinger model, a general formula that incorporates, for sufficiently small fermion mass, all the bound-state mass poles of the massive Schwinger model. As an illustration we perturbatively compute the masses of the three lowest bound states.Comment: 11 pages, 7 figures, needed macro: psbox.te

The symmetries of the Dirac--Pauli equation in two and three dimensions

We calculate all symmetries of the Dirac-Pauli equation in two-dimensional and three-dimensional Euclidean space. Further, we use our results for an investigation of the issue of zero mode degeneracy. We construct explicitly a class of multiple zero modes with their gauge potentials.Comment: 22 pages, Latex. Final version as published in JMP. Contains an additional subsection (4.2) with the explicit construction of multiple zero mode

Judicial Reform under Authoritarianism: The Role of Regime–Judiciary Relations during Periods of Political Competition (SWP 46)

According to the so-called Insurance Theory of judicial empowerment, incumbent elites create independent and empowered courts in order to protect themselves and their policies after leaving office. In many authoritarian regimes, however, elites have very poor relations with their judiciaries, and therefore will have little reason to expect fair treatment from the courts in the event of their overthrow. Drawing on case studies from Sudan, Egypt, Mexico, and Argentina, this article shows that when regime–judiciary relations are poor, the logic of the Insurance Theory is reversed and increased political competition leads to less judicial independence instead of more. It then presents a revised version of the Insurance Theory better suited to authoritarian cases. &nbsp

Ensuring Access to Emerging COVID-19 Treatments Through Medicare Reimbursement Policy

Effective pharmaceutical treatments for coronavirus disease 2019 (COVID-19) are urgently needed, and there has been an explosion of research into compounds with potential efficacy against the disease. The highest-profile success to date is Gilead Sciences’ antiviral remdesivir, which received an Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) after preliminary data showed that it may speed patients’ time to recovery.1 Gilead is just beginning to sell remdesivir commercially. However, Medicare reimbursement policy is likely to pose challenges for hospitals seeking to administer remdesivir and other COVID-19 drugs to patients. Policy makers ought to think critically about addressing these policy barriers

Normalization of the chiral condensate in the massive Schwinger model

Within mass perturbation theory, already the first order contribution to the chiral condensate of the massive Schwinger model is UV divergent. We discuss the problem of choosing a proper normalization and, by making use of some bosonization results, we are able to choose a normalization so that the resulting chiral condensate may be compared, e.g., with lattice data.Comment: Latex file, 8 pages, 1 figure, needed macro: psbox.te

The Schwinger Mass in the Massive Schwinger Model

We derive a systematic procedure to compute Green functions for the massive Schwinger model via a perturbation expansion in the fermion mass. The known exact solution of the massless Schwinger model is used as a starting point. We compute the corrections to the Schwinger mass up to second order.Comment: Latex, 7 pages, no figure

THE DYSON-SCHWINGER EQUATION FOR A MODEL WITH INSTANTONS - THE SCHWINGER MODEL

Using the exact path integral solution of the Schwinger model -- a model where instantons are present -- the Dyson-Schwinger equation is shown to hold by explicit computation. It turns out that the Dyson-Schwinger equation separately holds for every instanton sector. This is due to Theta-invariance of the Schwinger model.Comment: LATEX file 11 pages, no figure

Multiple zero modes of the Dirac operator in three dimensions

One of the key properties of Dirac operators is the possibility of a degeneracy of zero modes. For the Abelian Dirac operator in three dimensions the construction of multiple zero modes has been sucessfully carried out only very recently. Here we generalise these results by discussing a much wider class of Dirac operators together with their zero modes. Further we show that those Dirac operators that do admit zero modes may be related to Hopf maps, where the Hopf index is related to the number of zero modes in a simple way.Comment: Latex file, 20 pages, no figure

Building for Culture: How Municipal Ownership of Cultural Facilities Influences Annual Arts Funding in American Cities

This thesis explores how local government support for arts and culture varies across 24 American cities. It has proven to be challenging for researchers to accurately measure municipal arts support. Research on cultural policy has also often focused on the federal level, despite total city expenditures far exceeding national or state government support. This thesis attempts to take an accurate pulse of city expenditures in 2017 and correlates those spending levels to the variation in city ownership of arts facilities. Rooted in the historical perspectives of the ‘new institutionalism’ and path-dependency, this paper argues that past decisions about taking ownership of cultural facilities bind budgetary decision-makers in the present; the resulting relationships, or lack of them, drive the great variation in cultural support in American cities. Tracing annual funding in the present day to historical decisions made during a city’s foundation period provides a better understanding of how cities make these budgetary decisions, or perhaps have them made for them