Closed form solution of Lindblad master equations without gain

We present a closed form solution to the eigenvalue problem of a class of master equations that describe open quantum system with loss and dephasing but without gain. The method relies on the existence of a conserved number of excitation in the Hamiltonian part and that none of the Lindblad operators describe an excitation of the system. In the absence of dephasing Lindblad operators, the eigensystem of the Liouville operator can be constructed from the eigenvalues and eigenvectors of the effective non-Hermitian Hamiltonian used in the quantum jump approach. Open versions of spin chains, the Tavis-Cummings model and coupled Harmonic oscillators without gain can be solved using this technique.Comment: 9 page

Mass density of the Earth from a Gravito-Electro-Magnetic 5D vacuum

We calculate the mass density of the Earth using a Gravito-Electro-Magnetic theory on an extended 5D Schwarzschild-de Sitter metric, in which we define the vacuum. Our results are in very good agreement with that of the Dziewonski-Anderson model.Comment: 9 pages, 2 figure

THE POLITICAL ECONOMY OF LABOR REFORM IN COLOMBIA

This paper analyzes the entire reformist effort that spans from 1990 until 2002, emphasizing the second wave that ended with the issuing of a new labor code in 2002. A successful reform has to surpass a set of deals" along the streamline of design, consensus building within civil society, submission to Congress and parliamentary debate, before it gets approved. The paper presents the story of two failed attempts for producing these "deals" within the government, along with labor unions and private sector firm confederations, before the 2002 labor reform was finally enacted. It shows what economic and social considerations created the need for reform, describes the actual policy changes implemented and evaluates their impact. The paper delves deep into the political aspects of the reform effort. Public officials of two governments pursued different lines of reform, discussion strategies and mechanisms for creating consensus, before the initiative gained momentum and circumvented key obstacles. The text of the 2002 reform proposal changed little during five years, but received important additions in the floor of Congress, with little technical support. Finally, an interesting dispute between lawyers and economists is presented regarding the role of the labor code for job creation and its function in the economic cycle. In the case of this reform, economists believed more on the computed elasticities, while lawyers believed more in the stability of established rules and in the limited role of norms. Economists should pay more attention to the workings of the political economy of reform and to the "life cycle of government", both of them critical for success."labor reform