Quasi-particles and their absence in photoemission spectroscopy

The elucidation of Landau Fermi liquid quasi-particles and their absence in strongly correlated electron systems lies at the heart of modern research on the quantum mechanics of electrons in condensed matter. Photoemission spectroscopy of the single particle spectral function is a central experimental tool for such studies. A general paradigm of quasi-particle formation is the Fermi level resonance associated with the Kondo physics of the Anderson impurity model, an effective self consisent version of which is utilized in dynamic mean field theories of general lattice systems which may or may not literally display Kondo physics. A general paradigm of quasi-particle absence is the Luttinger liquid physics of the Tomonaga-Luttinger model. This paper presents an overview of the theoretical ideas and shows examples in photoemission spectra, taken from the work of the author and his collaborators, of quasi-particle formation in impurity and lattice Kondo and non-Kondo correlated electron systems, contrasted with quasi-particle absence in a quasi-one-dimensional system.Comment: 28 pages, 9 figures, APS Frank Isakson Prize pape

Addressing Resource Gaps in the U.S. Health Care Safety Net: An Assessment of the Free Clinic Network

Based on a survey of free clinics serving uninsured low-income patients, examines the resource constraints limiting the expansion of healthcare services provided, including the high costs of labs, equipment, and medication. Makes recommendations

Collective Coordinate Action for Charged Sigma-Model Vortices in Finite Geometries

In this Letter the method of Lund is applied to formulate a variational principle for the motion of charged vortices in an effective non-linear Schr\"{o}dinger field theory describing finite size two-dimensional quantum Hall samples under the influence of an arbitrary perpendicular magnetic field. Freezing out variations in the modulus of the effective field yields a $U(1)$ sigma-model. A duality transformation on the sigma-model reduces the problem to finding the Green function for a related electrostatics problem. This duality illuminates the plasma analogy to the Laughlin wave function.Comment: 7 pp., Plain TeX (macros included), MAD/TH-92-0

Witold Gombrowicz: Diary of a Playwright

The article discusses Polish writer Witold Gombrowicz\u27s Diary as a playwright, his theatrical career, and states that his image in the public entertainment field was said to be influenced by his self-absorbed character

Fiddling While Rome Burns: The Story of the Federal Rules and Experts

It is a great privilege and honor to be asked to participate in even a small way in the work of the rules advisory process. The topic today is important, and there is a lot of brain power in the room, so much that we may be able to solve some of the problems posed by forensics. Knowledge is certainly advancing, and generally reliable consensus on some of the issues plaguing the use of forensic experts at trial may be decided in the sense that any issue is decided in a typical scientific field. More or less definitely resolving scientific controversies will have two important consequences in the real world. First, certain issues will not really be the subject of litigation, notwithstanding the conventional but false belief that there can be no directed verdicts, even partial directed verdicts, in criminal cases. In fact, certain issues will already have been decided, such as many issues concerning the scientific foundations of DNA testing. Second, certain other issues will continue to be the foundation upon which qualified experts offer opposing opinions

The Beautiful Mystery: Examining Jonathan Edwards’ View of Marriage

In contemporary evangelical circles, Jonathan Edwards has gained wide popularity for his theological writings and vital role in the First Great Awakening. However, despite these often romanticized views, Edwards nonetheless stood in the midst of an eighteenth century society that began to develop new norms for sexual practice and new legal guidelines to support them. In order to combat what he saw to be a decaying moral culture, Edwards took a strong stance on marital issues, often to the displeasure of his congregation. What lay behind these convictions was a deep theological understanding of the sanctity of marriage. These views, although not new to the history of Christian thought, were uniquely reinvigorated by Edwards to a Calvinist generation that had recently abandoned them. It is both Edwards’ theology of marriage and reinforcement of its practice that not only make him a unique preacher for his time, but also a worthy study for Evangelicals today in the midst of modern marital controversies