Overcoming the su(2^n) sufficient condition for the coherent control of n-qubit systems

We study quantum systems with even numbers N of levels that are completely state-controlled by unitary transformations generated by Lie algebras isomorphic to sp(N) of dimension N(N+1)/2. These Lie algebras are smaller than the respective su(N) with dimension N^2-1. We show that this reduction constrains the Hamiltonian to have symmetric energy levels. An example of such a system is an n-qubit system. Using a geometric representation for the quantum wave function of a finite system, we present an explicit example that shows a two-qubit system can be controlled by the elements of the Lie algebra sp(4) (isomorphic to spin(5) and so(5)) with dimension ten rather than su(4) with dimension fifteen. These results enable one to envision more efficient algorithms for the design of fields for quantum-state engineering, and they provide more insight into the fundamental structure of quantum control.Comment: 13 pp., 2 figure

AGRI-ENVIRONMENTAL PROGRAMS IN THE UNITED STATES AND THE EUROPEAN UNION

Agricultural and Food Policy, Environmental Economics and Policy,

Agri-environmental Policy in the European Union: Who's in Charge?

The EU has argued that some agricultural subsidies are needed to provide the optimal amount of externalities (both positive and negative) produced by agriculture. The argument is that agriculture is "multifunctional" and externalities such as rural development and landscape would be underproduced, while some forms of pollution (such as nitrogen runoff) would be overproduced without government intervention. Meanwhile, the United States has raised the concern that multifunctionality is primarily an argument to transfer income to producers. One way to try and determine how much of these non-commodity payments are directed to externalities and how much is intended to distribute income to producers is to analyze the variation of the programs among the different member states of the EU. We estimate the degree to which environmental characteristics, agricultural characteristics and political economy variables determine the objective and amount of funding each member states uses to address environmental externalities (both positive and negative). Results indicate that little of the variance in agri-environmental expenditure can be explained by the difference in negative externalities, neither is there clear evidence that the payments are substituting for traditional agricultural subsidies. However, demand for environmental services and political variables seem to be the driving motivators behind a country's decision to spend money on agri-environmental programs.Environmental Economics and Policy,

CAUSES OF MULTIFUNCTIONALITY: EXTERNALITIES OR POLITICAL PRESSURE

Resource /Energy Economics and Policy,

Lightlike infinity in GCA models of Spacetime

This paper discusses a 7 dimensional conformal geometric algebra model for spacetime based on the notion that spacelike and timelike infinities are distinct. I show how naturally of the dimensions represents the lightlike infinity and appears redundant in computations, yet usefull in interpretationComment: 12 page

Event related potentials reveal that increasing perceptual load leads to increased responses for target stimuli and decreased responses for irrelevant stimuli

This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.Peer reviewedPublisher PD

Agri-environmental Policy in the European Union: Who's in Charge?

European Union (EU) agri-environmental programmes (AEPs) represent a significant step in the region's efforts to decouple agricultural output from production and export subsidies. While AEPs comprise only a small share of EU agricultural support, they have two possible external impacts: 1) the composition of the EU's imports and exports may change as their producers become more market responsive; and 2) the WTO's Green Box (subsides considered minimally trade distorting and hence not disciplined) may become increasingly contentious. Our concern is with the drivers of AEPs in the EU and their implications for Canada.Environmental Economics and Policy,

Causes of Multifunctionality: Externalities or Political Pressure?

The EU has argued that some agricultural subsidies are needed to provide the optimal amount of externalities (both positive and negative) produced by agriculture. The argument is that agriculture is "multifunctional" and externalities such as rural development and landscape would be underproduced, while some forms of pollution (such as nitrogen runoff) would be overproduced without government intervention. Meanwhile, the United States has raised the concern that multifunctionality is primarily an argument to transfer income to producers. In this paper, we discuss the motivation for the EU agri-environmental measures and empirically test for those underlying causes. We find that the programs are not targeted at those regions with the highest environmental need, but neither are they purely a substitute for traditional forms of agricultural subsidies. Demand for general environmental expenditure does influence agri-environmental expenditure as well, as does political structure.Environmental Economics and Policy,