Applications of Basis Light-Front Quantization to QED

Hamiltonian light-front quantum field theory provides a framework for calculating both static and dynamic properties of strongly interacting relativistic systems. Invariant masses, correlated parton amplitudes and time-dependent scattering amplitudes, possibly with strong external time-dependent fields, represent a few of the important applications. By choosing the light-front gauge and adopting an orthonormal basis function representation, we obtain a large, sparse, Hamiltonian matrix eigenvalue problem for mass eigenstates that we solve by adapting ab initio no-core methods of nuclear many-body theory. In the continuum limit, the infinite matrix limit, we recover full covariance. Guided by the symmetries of light-front quantized theory, we adopt a two-dimensional harmonic oscillator basis for transverse modes that corresponds with eigensolutions of the soft-wall anti-de Sitter/quantum chromodynamics (AdS/QCD) model obtained from light-front holography. We outline our approach and present results for non-linear Compton scattering, evaluated non-perturbatively, where a strong and time-dependent laser field accelerates the electron and produces states of higher invariant mass i.e. final states with photon emission.Comment: 6 pages, 4 figures, proceedings for Lightcone 2012 conference at Delhi, Indi

D-SLATS: Distributed Simultaneous Localization and Time Synchronization

Through the last decade, we have witnessed a surge of Internet of Things (IoT) devices, and with that a greater need to choreograph their actions across both time and space. Although these two problems, namely time synchronization and localization, share many aspects in common, they are traditionally treated separately or combined on centralized approaches that results in an ineffcient use of resources, or in solutions that are not scalable in terms of the number of IoT devices. Therefore, we propose D-SLATS, a framework comprised of three different and independent algorithms to jointly solve time synchronization and localization problems in a distributed fashion. The First two algorithms are based mainly on the distributed Extended Kalman Filter (EKF) whereas the third one uses optimization techniques. No fusion center is required, and the devices only communicate with their neighbors. The proposed methods are evaluated on custom Ultra-Wideband communication Testbed and a quadrotor, representing a network of both static and mobile nodes. Our algorithms achieve up to three microseconds time synchronization accuracy and 30 cm localization error

Linear-Matrix-Inequality-Based Solution to Wahba’s Problem

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140644/1/1.g000132.pd

Policy Implications of Weak Patent Rights

Patents vary substantially in the degree of protection provided against unauthorized imitation. In this chapter we explore a range of work addressing the economic and policy implications of weak patents--patents that have a significant probability of being overturned or being circumvented relatively easily---on innovation and disclosure incentives, antitrust policy, and organizational incentives and entrepreneurial activity. Weak patents cause firms to rely more heavily on secrecy. Thus, the competitive environment is characterized by private information about the extent of the innovator\u27s know-how. In such an environment weak patents increase the likelihood of imitation and infringement, reduce the amount of knowledge publicly disclosed, and potentially reduce the incentives to innovate. The discussion also highlights some implications of weak patents for antitrust policy. Weak patent rights increase the likelihood of patent litigation over commercially valuable patents and raise the specter of anticompetitive settlements. Encouraging the antitrust agencies to refer some patents for re-examination by the patent office would facilitate investigation of potentially anticompetitive IP settlements. Finally, we note some implications for weak property rights in settings involving employee-inventors and employee misuse of confidential information. In the former case an increase in the strength of legal property rights such as patents reduces the employer\u27s ability to prevent employees departing with valuable know-how, in part because a stronger property right increases the value of the employee\u27s start-up option. In the latter case, an increase in legal penalties for breach of confidentiality has the expected effect of decreasing such occurrences

Delay as Agenda Setting *

Abstract In this paper we examine a class of dynamic decision-making processes that involve endogenous commitment. Our analysis is relevant to group decision making settings as well as to hierarchical decision making settings in which, for example, subordinates attempt to influence their superiors. An inability to commit leads to the possibility of strategic delay by decision participants who differ in their preferences and are limited by the resources they can allocate to influencing decisions. We focus on sources of delay caused by the strategic interaction of decision makers over time and find that the opportunity to delay decisions leads the participants to sometimes act against their short-run interests. Two classes of activity of this type emerge which we refer to as focusing and pinning. We also explore how strategic delay alters the benefits from agenda setting

High voltage coefficient piezoelectric materials and their applications

The piezoelectric dij coefficient is often regarded in materials science as the most important figure of merit of piezoelectric performance. For many applications, the piezoelectric gij coefficient which correlates to voltage output and sensitivity of a piezoelectric material can be considered of equal or increased importance, however is often an overlooked parameter in materials science literature. The aim of this review is to highlight the importance of this parameter and to provide insight into the mechanisms that drive a high piezoelectric voltage coefficient in single crystal, polycrystalline, and composite form. For bulk ceramics, special attention is given to tetragonal systems due to the availability of electrical and crystallographic data allowing for a clear structure-property relation. Orthorhombic and rhombohedral systems are mentioned and specific cases highlighted, however investigating structure-property relations is difficult due to the lack of crystallographic datasets. Composite materials have been the forefront of high gij piezoelectric materials over the decades and are therefore also considered in both ceramic-matrix and polymer-matrix form. An overview of applications in medical, energy, fishing and defence industries where a high gij is desirable are considered and the scientific and commercial considerations that must be made for the transition from laboratory to industry are discussed from the perspective of integrating new piezoelectric materials into sonar devices