Real space renormalization group for twisted lattice N=4 super Yang-Mills

A necessary ingredient for our previous results on the form of the long distance effective action of the twisted lattice N=4 super Yang-Mills theory is the existence of a real space renormalization group which preserves the lattice structure, both the symmetries and the geometric interpretation of the fields. In this brief article we provide an explicit example of such a blocking scheme and illustrate its practicality in the context of a small scale Monte Carlo renormalization group calculation. We also discuss the implications of this result, and the possible ways in which to use it in order to obtain further information about the long distance theory.Comment: 15 pages, 3 figure

O(a) improvement of lattice QCD with two flavors of Wilson quarks

We consider O(a) improvement for two flavor lattice QCD. The improvement term in the action is computed non-perturbatively for a large range of the bare coupling. The position of the critical line and higher order lattice artifacts remaining after improvement are estimated. We also discuss the behavior of the HMC algorithm in our simulations.Comment: Few entries in Table 1 corrected - no other change

Fundamental parameters of QCD

The theory of strong interactions, QCD, is described in terms of a few parameters, namely the strong coupling constant alpha_s and the quark masses. We show how these parameters can be determined reliably using computer simulations of QCD on a space-time lattice, and by employing a finite-size scaling method, which allows to trace the energy dependence of alpha_s and quark masses over several orders of magnitude. We also discuss methods designed to reduce the effects of finite lattice spacing and address the issue of computer resources required.Comment: Contribution to proceedings of NIC Symposium 2001, 13 pages, 7 figures, uses nic-series.cl

The Federal Reserve: A Study in Soft Constraints

In response to the greatest financial crisis since the Great Depression, the Federal Reserve (the Fed) took a number of unprecedented steps to try to minimize the adverse economic consequences that would follow. From providing liquidity injections to save companies like Bear Stearns and American International Group (AIG) to committing to a prolonged period of exceptionally low interest rates and buying massive quantities of longer-term securities to further reduce borrowing costs, the Fed\u27s response to the 2007 through 2009 financial crisis (the Crisis) has been creative and aggressive. These actions demonstrated that the Fed is uniquely powerful among federal agencies, and its authority is even greater than most had previously appreciated. They also made clear that the Fed\u27s actions can have significant distributional consequences, in addition to affecting the health of the overall economy. These developments have led many to suggest that the Fed should be far more accountable, or less powerful, than it currently is. Attacks on the Fed\u27s power are not new. Vesting so much power in the hands of an unelected few inevitably raises questions about legitimacy, for which there are no easy answers. Using traditional mechanisms to make the Fed more politically accountable could substantially impede the Fed\u27s capacity to achieve the aims assigned to it. Yet, as reflected in the demise of the First and Second Banks of the United States, ignoring these concerns can prove even more detrimental. In the United States, the outer limits of independence are delineated by the Constitution, but important questions regarding legitimacy and accountability arise far shy of the Constitution\u27s outer bounds. Many of these issues are not specific to the Fed, and there is a robust body of literature examining these dynamics. Nonetheless, this article suggests that many of the forces that influence the degree of independence that the Fed enjoys in practice are largely overlooked in much of this literature. Those overlooked forces are soft constraints, a range of forces that are not legally binding and that can even be a little fuzzy in application, but that nonetheless impose meaningful limits on how the Fed exercises its seemingly vast authority. This article illustrates the power of soft constraints by examining the role that two particular soft constraints – principled norms and the Fed Chair\u27s concern with her reputation – have played in shaping Fed action over the last hundred years

Making things happen : a model of proactive motivation

Being proactive is about making things happen, anticipating and preventing problems, and seizing opportunities. It involves self-initiated efforts to bring about change in the work environment and/or oneself to achieve a different future. The authors develop existing perspectives on this topic by identifying proactivity as a goal-driven process involving both the setting of a proactive goal (proactive goal generation) and striving to achieve that proactive goal (proactive goal striving). The authors identify a range of proactive goals that individuals can pursue in organizations. These vary on two dimensions: the future they aim to bring about (achieving a better personal fit within one’s work environment, improving the organization’s internal functioning, or enhancing the organization’s strategic fit with its environment) and whether the self or situation is being changed. The authors then identify “can do,” “reason to,” and “energized to” motivational states that prompt proactive goal generation and sustain goal striving. Can do motivation arises from perceptions of self-efficacy, control, and (low) cost. Reason to motivation relates to why someone is proactive, including reasons flowing from intrinsic, integrated, and identified motivation. Energized to motivation refers to activated positive affective states that prompt proactive goal processes. The authors suggest more distal antecedents, including individual differences (e.g., personality, values, knowledge and ability) as well as contextual variations in leadership, work design, and interpersonal climate, that influence the proactive motivational states and thereby boost or inhibit proactive goal processes. Finally, the authors summarize priorities for future researc

Non-perturbative Pion Matrix Element of a twist-2 operator from the Lattice

We give a continuum limit value of the lowest moment of a twist-2 operator in pion states from non-perturbative lattice calculations. We find that the non-perturbatively obtained renormalization group invariant matrix element is _{RGI} = 0.179(11), which corresponds to ^{MSbar}(2 GeV) = 0.246(15). In obtaining the renormalization group invariant matrix element, we have controlled important systematic errors that appear in typical lattice simulations, such as non-perturbative renormalization, finite size effects and effects of a non-vanishing lattice spacing. The crucial limitation of our calculation is the use of the quenched approximation. Another question that remains not fully clarified is the chiral extrapolation of the numerical data.Comment: 26 pages, 10 figures, v2: final version, accepted for publication in EPJ

Theorizing the Law/Politics Distinction: Neutral Principles, Affirmative Action, and the Enduring Insight of Paul Mishkin

Early in his career Mishkin saw that the law could be apprehended from two distinct and in part incompatible perspectives: from the internal perspective of a faithful practitioner and from the external perspective of the general public. If the social legitimacy of the law as a public institution resides in the latter, the legal legitimacy of the law as a principled unfolding of professional reason inheres in the former. Mishkin came to believe that although the law required both forms of legitimacy, there was nevertheless serious tension between them, and he dedicated his scholarly career to attempting to theorize this persistent but necessary tension, which he conceived almost as a form of antinomy. In this article we pay tribute to Mishkin\u27s quest for understanding. We argue that the tension identified by Mishkin is significant and unavoidable, but that it is also exaggerated because it presupposes an unduly stringent separation between professional reason and popular values. In our view the law/politics distinction is both real and suffused throughout with ambiguity and uncertainty. The existence of the law/politics distinction creates the possibility of the rule of law, but the ragged and blurred boundaries of that distinction vivify the law by infusing it with the commitments and ideals of those whom the law purports to govern