Insensitivity of Ion Motional Heating Rate to Trap Material over a Large Temperature Range

We present measurements of trapped-ion motional-state heating rates in niobium and gold surface-electrode ion traps over a range of trap-electrode temperatures from approximately 4 K to room temperature (295 K) in a single apparatus. Using the sideband-ratio technique after resolved-sideband cooling of single ions to the motional ground state, we find low-temperature heating rates more than two orders of magnitude below the room-temperature values and approximately equal to the lowest measured heating rates in similarly-sized cryogenic traps. We find similar behavior in the two very different electrode materials, suggesting that the anomalous heating process is dominated by non-material-specific surface contaminants. Through precise control of the temperature of cryopumping surfaces, we also identify conditions under which elastic collisions with the background gas can lead to an apparent steady heating rate, despite rare collisions.Comment: v1: 6 pages, 3 figures; v2: 7 pages, 3 figures, analysis of temperature dependence and calculation of effects of collisions expanded and improved, minor errors corrected in discussions of Johnson noise and collisions and in appendix

Atomistic subsemirings of the lattice of subspaces of an algebra

Let A be an associative algebra with identity over a field k. An atomistic subsemiring R of the lattice of subspaces of A, endowed with the natural product, is a subsemiring which is a closed atomistic sublattice. When R has no zero divisors, the set of atoms of R is endowed with a multivalued product. We introduce an equivalence relation on the set of atoms such that the quotient set with the induced product is a monoid, called the condensation monoid. Under suitable hypotheses on R, we show that this monoid is a group and the class of k1_A is the set of atoms of a subalgebra of A called the focal subalgebra. This construction can be iterated to obtain higher condensation groups and focal subalgebras. We apply these results to G-algebras for G a group; in particular, we use them to define new invariants for finite-dimensional irreducible projective representations.Comment: 14 page

Corporate Social Responsibility at Gap: An Interview with Eva Sage-Gavin

Gap Inc. is one of the world\u27s largest specialty retailers, with more than 3,000 stores and fiscal 2005 revenues of $16 billion. They operate four of the most recognized apparel brands in the world — Gap, Banana Republic, Old Navy and Forth & Towne. According to the company website “At Gap Inc., social responsibility isn\u27t just a catchphrase or a feel good initiative. It\u27s a reflection of who we are and how we operate as a company. To us, being socially responsible means striving to embed our values and ethics into everything we do — from how we run our business, to how we treat our employees, to how we impact the communities where we do business. In 2003 Gap Inc. was the first retailer to release a social responsibility report, offering a comprehensive overview of their approach to social responsibility. The report was broadly lauded for its willingness to be open and honest about both the successes and failures in this arena. In fact, this report won Business Ethics magazine\u27s Social Reporting Award for unprecedented honesty in reporting on factory conditions. Their 2004 Social Responsibility Report continued that discussion and provided new information on their progress, challenges, and new initiatives. Eva Sage-Gavin is Executive Vice President, Human Resources and Corporate Communications, of Gap Inc. In her role as Chief People Officer, she sets the strategy for the company\u27s communications and human resources operations worldwide, including staffing, diversity, rewards, recognition, employee benefits, learning and development, strategic change, and internal and external communications. She set aside time to provide more specifics to how and why Gap Inc. places so much emphasis on corporate social responsibility

Enterprise Liability and the Emerging Managed Health Care System

“Enterprise medical liability” is a term used to describe a system in which health care organizations bear responsibility for medical malpractice in addition to or instead of individual health professionals. Enterprise liability is in many senses a natural outgrowth of the increasing dependence of medical practice on institutional resources and expertise. Proposals for enterprise liability surfaced briefly from the academic literature into the political spotlight during the 1993-94 health care reform debate. At that time, objections to the concept as a basis for medical malpractice liability, even in a restructured health care system, were nearly universal. Just five years later, many of the groups vehemently opposing the Clinton malpractice reform have become vigorous supporters of managed care liability. Moreover, courts and legislatures are holding managed care organizations accountable for malpractice in ways superficially compatible with the Clinton proposal. In the process, however, enterprise liability has been transformed from a theory without a movement to a movement without a theory. This article explores why this happened, whether it is likely to be a transitory phase or a sustained trend, and what it portends for the public policy objectives of medical tort law. Part II of this article describes the theoretical justifications for imposing liability for medical malpractice on managed care organizations, emphasizing proposals that were made in connection with the national health care reform debate. Part III explains why enterprise liability failed to attract support in 1993-94. Part IV discusses the very different attitudes that prevail in 1998, and details the legal manifestations of the current movement to expand malpractice liability in managed care. Parts V and VI of the article analyze the relationship among theoretical constructs of enterprise liability, the reality of today’s managed care marketplace, and the legal response managed care has provoked. Specifically, Part V outlines several respects in which the market and the legal system have moved away from characteristics that previously made enterprise liability desirable, and Part VI identifies potentially significant trends that could lead to a rapprochement between our health care system and the public policy justifications for extending malpractice liability to managed care organizations. Finally, Part VII suggests that federal legislation is necessary for malpractice liability to serve socially constructive purposes in managed care, and identifies a set of principles that should guide future legislative action

Managed Care’s Crimea: Medical Necessity, Therapeutic Benefit, and the Goals of Administrative Process in Health Insurance

En brotyp som är vanlig bland brokonstruktioner är plattrambron. Denna brotyp byggs både med slak- och spännarmering. Det är dock vanligare att bygga med slakarmering än spännarmering, vilket övervägs särskilt då spännvidderna är ungefär 25- 30 meter eller mer. Inledningsvis har en noggrann litteraturstudie genomförts tillsammans med en intervju av en kunnig brokonstruktör för att säkerställa en interaktion mellan teori och aktuell praxis. Detta arbete har haft ett huvudmål, vilket är att ur ett struktur- och kostnadsperspektiv jämföra och utvärdera hur behovet av slakarmering varierar i en plattrambros farbana då spännvidder varieras och betongtvärsnitt ändras. Arbetet har utförts med hjälp av finita elementprogrammet ”Brigade Standard”, vilket erbjuder en tre-dimensionell strukturanalys. Fyra olika tvärsnitt för spännvidder mellan 10-20 meter analyseras. Dimensioner på brodelar bestäms med hjälp av tumregler samt generella råd från intervjuperson; höjd i fält enligt L/20, L/25, L/30 samt L/35, där L är spännvidden. Resultatet visar främst att för ökade spännvidder mot 20 meter ökar lasteffekten på grund av egentyngd drastiskt och då särskilt det tvärsnitt som är störst, det vill säga L/20. Vidare visas även att slankare tvärsnitt resulterar i aningen högre armeringsmängd. Dock påverkas betongkostnaden i större utsträckning av slankare tvärsnitt och särskilt större spännvidder. Även om större spännvidd och slankare tvärsnitt föranleder ett större armeringsbehov, fås en lägre totalkostnad. Det bör noteras att priset på betong och stål är starkt beroende av konjunktur och tillgång till material. Denna studie kan bli ännu intressantare då priset varierar kraftigt för stål och föranleder att betongpriset blir mindre dominerande än vad det är idag. Huvudprodukten från detta arbete är att med hjälp av tabeller och nya priser kunna beräkna en preliminär totalkostnad för plattrambrons farbana för olika spännvidder och hur olika tvärsnittsalternativ påverkar denna kostnad

Managed Care’s Crimea: Medical Necessity, Therapeutic Benefit, and the Goals of Administrative Process in Health Insurance

This Essay explores the concept of medical necessity as it has evolved in the judicial and administrative oversight of managed care. The goals of the Essay are to illustrate the range of plausible rationales for establishing administrative procedures to govern medical necessity disputes, and to demonstrate the difficulty of incorporating into those procedures the most important professional and social responsibilities of managed care in today’s health care system. Part I of the Essay explains the ideological and practical significance of medical necessity as managed care has evolved. Part II examines medical necessity as a legal problem, and questions whether current independent review programs match social needs. Part III offers an alternative perspective on oversight of decisionmaking in managed care that emphasizes therapeutic effect rather than contractual enforcement. Part IV describes improvements in both independent review and overall medical necessity policy that would better serve therapeutic objectives. Among other things, the Essay suggests that independent review procedures should be different for insured individuals who are severely or chronically ill than for those who are only occasional users of health care services

(SL(N),q)(SL(N),q)-opers, the qq-Langlands correspondence, and quantum/classical duality

A special case of the geometric Langlands correspondence is given by the relationship between solutions of the Bethe ansatz equations for the Gaudin model and opers - connections on the projective line with extra structure. In this paper, we describe a deformation of this correspondence for $SL(N)$. We introduce a difference equation version of opers called $q$-opers and prove a $q$-Langlands correspondence between nondegenerate solutions of the Bethe ansatz equations for the XXZ model and nondegenerate twisted $q$-opers with regular singularities on the projective line. We show that the quantum/classical duality between the XXZ spin chain and the trigonometric Ruijsenaars-Schneider model may be viewed as a special case of the $q$-Langlands correspondence. We also describe an application of $q$-opers to the equivariant quantum $K$-theory of the cotangent bundles to partial flag varieties.Comment: v3: 32 pages, 2 figures; minor revisions, to appear in Commun. Math. Phy

Trapped-Ion Quantum Computing: Progress and Challenges

Trapped ions are among the most promising systems for practical quantum computing (QC). The basic requirements for universal QC have all been demonstrated with ions and quantum algorithms using few-ion-qubit systems have been implemented. We review the state of the field, covering the basics of how trapped ions are used for QC and their strengths and limitations as qubits. In addition, we discuss what is being done, and what may be required, to increase the scale of trapped ion quantum computers while mitigating decoherence and control errors. Finally, we explore the outlook for trapped-ion QC. In particular, we discuss near-term applications, considerations impacting the design of future systems of trapped ions, and experiments and demonstrations that may further inform these considerations.Comment: The following article has been submitted to Applied Physics Review

Isomonodromic deformations of connections with singularities of parahoric formal type

In previous work, the authors have developed a geometric theory of fundamental strata to study connections on the projective line with irregular singularities of parahoric formal type. In this paper, the moduli space of connections that contain regular fundamental strata with fixed combinatorics at each singular point is constructed as a smooth Poisson reduction. The authors then explicitly compute the isomonodromy equations as an integrable system. This result generalizes work of Jimbo, Miwa, and Ueno to connections whose singularities have parahoric formal type.Comment: 32 pages. One of the main theorems (Theorem 5.1) has been significantly strengthened. It now states that the isomonodromy equations give rise to an integrable system on the moduli space of framed connections with fixed combinatorics instead of only on a principal GL_n bundle over this space. Sections 5 and 6 have been substantially rewritte