Information processing and the second law of thermodynamics: an inclusive, Hamiltonian approach

We obtain generalizations of the Kelvin-Planck, Clausius, and Carnot statements of the second law of thermodynamics, for situations involving information processing. To this end, we consider an information reservoir (representing, e.g. a memory device) alongside the heat and work reservoirs that appear in traditional thermodynamic analyses. We derive our results within an inclusive framework in which all participating elements -- the system or device of interest, together with the heat, work and information reservoirs -- are modeled explicitly by a time-independent, classical Hamiltonian. We place particular emphasis on the limits and assumptions under which cyclic motion of the device of interest emerges from its interactions with work, heat, and information reservoirs.Comment: 14 pages, 4 figure

Reconsidering Economic Relations and Political Citizenship in the New Iberia of the New Europe: Some Lessons from the Fifteenth Anniversary of the Accession of Portugal and Spain to the European Union. CES Working Paper, no. 94, 2003

The purpose of this paper is to use the fifteenth anniversary of the accession of Portugal and Spain to the European Union as an opportunity to reflect on what has happened to both countries since 1986. It examines the integration process and how it has affected political, economic and social developments in Portugal and in Spain over the last fifteen years. In our view, and on balance, Spain and Portugal have benefited from accession. Since the last century, the obsession of Spanish and Portuguese reformists has been to make up the lost ground with modernized Europe. EU membership has been a critical step in this direction. The record of the past fifteen years is that this dream is becoming an economic reality. Despite impressive achievements, however, namely, since 1986, Portugal’s average per capita income has grown from 56 percent of the EU average to about 74 percent, whereas Spain’s has grown to 83 percent—both Iberian countries still have a long way to go to reach the EU average wealth. In addition, the question of Iberian and/or European citizenship, and its impact on the Portuguese and Spanish, remains open

A Bramble-Pasciak conjugate gradient method for discrete Stokes equations with random viscosity

We study the iterative solution of linear systems of equations arising from stochastic Galerkin finite element discretizations of saddle point problems. We focus on the Stokes model with random data parametrized by uniformly distributed random variables and discuss well-posedness of the variational formulations. We introduce a Bramble-Pasciak conjugate gradient method as a linear solver. It builds on a non-standard inner product associated with a block triangular preconditioner. The block triangular structure enables more sophisticated preconditioners than the block diagonal structure usually applied in MINRES methods. We show how the existence requirements of a conjugate gradient method can be met in our setting. We analyze the performance of the solvers depending on relevant physical and numerical parameters by means of eigenvalue estimates. For this purpose, we derive bounds for the eigenvalues of the relevant preconditioned sub-matrices. We illustrate our findings using the flow in a driven cavity as a numerical test case, where the viscosity is given by a truncated Karhunen-Lo\`eve expansion of a random field. In this example, a Bramble-Pasciak conjugate gradient method with block triangular preconditioner outperforms a MINRES method with block diagonal preconditioner in terms of iteration numbers.Comment: 19 pages, 1 figure, submitted to SIAM JU

Classical and quantum shortcuts to adiabaticity for scale-invariant driving

A shortcut to adiabaticity is a driving protocol that reproduces in a short time the same final state that would result from an adiabatic, infinitely slow process. A powerful technique to engineer such shortcuts relies on the use of auxiliary counterdiabatic fields. Determining the explicit form of the required fields has generally proven to be complicated. We present explicit counterdiabatic driving protocols for scale-invariant dynamical processes, which describe for instance expansion and transport. To this end, we use the formalism of generating functions, and unify previous approaches independently developed in classical and quantum studies. The resulting framework is applied to the design of shortcuts to adiabaticity for a large class of classical and quantum, single-particle, non-linear, and many-body systems.Comment: 17 pages, 5 figure

Employment generation in rural Africa : mid-term results from an experimental evaluation of the Youth Opportunities Program in Northern Uganda

Can cash transfers promote employment and reduce poverty in rural Africa? Will lower youth unemployment and poverty reduce the risk of social instability? The authors experimentally evaluate one of Uganda's largest development programs, which provided thousands of young people nearly unconditional, unsupervised cash transfers to pay for vocational training, tools, and business start-up costs. Mid-term results after two years suggest four main findings. First, despite a lack of central monitoring and accountability, most youth invest the transfer in vocational skills and tools. Second, the economic impacts of the transfer are large: hours of non-household employment double and cash earnings increase by nearly 50 percent relative to the control group. The authors estimate the transfer yields a real annual return on capital of 35 percent on average. Third, the evidence suggests that poor access to credit is a major reason youth cannot start these vocations in the absence of aid. Much of the heterogeneity in impacts is unexplained, however, and is unrelated to conventional economic measures of ability, suggesting we have much to learn about the determinants of entrepreneurship. Finally, these economic gains result in modest improvements in social stability. Measures of social cohesion and community support improve mildly, by roughly 5 to 10 percent, especially among males, most likely because the youth becomes a net giver rather than a net taker in his kin and community network. Most strikingly, we see a 50 percent fall in interpersonal aggression and disputes among males, but a 50 percent increase among females. Neither change seems related to economic performance nor does social cohesion a puzzle to be explored in the next phase of the study. These results suggest that increasing access to credit and capital could stimulate employment growth in rural Africa. In particular, unconditional and unsupervised cash transfers may be a more effective and cost-efficient forming of large-scale aid than commonly believed. A second stage of data collection in 2012 will collect longitudinal economic impacts, additional data on political violence and behavior, and explore alternative theoretical mechanisms.Debt Markets,Labor Policies,Economic Theory&Research,Primary Education,Educational Sciences

A deep Chandra observation of Abell 4059: a new face to radio-mode AGN feedback?

A deep Chandra observation of the cooling core cluster Abell 4059 (A4059) is presented. Previous studies have found two X-ray cavities in the central regions of A4059 together with a ridge of X-ray emission 20kpc south-west of the cluster center. These features are clearly related to the radio galaxy PKS2354-35 which resides in the cD galaxy. Our new data confirm these previous findings and strengthen previous suggestions that the south-western ridge is colder and denser than, but in approximate pressure equilibrium with, the surrounding ICM atmosphere. In addition, we find evidence for a weak shock that wraps around the north and east sides of the cavity structure. Our data allow us to map the 2-dimensional distribution of metals in the ICM of A4059 for the first time. We find that the SW ridge possesses an anomalously high (super-solar) metalicity. The unusual morphology, temperature structure and metal distribution all point to significant asymmetry in the ICM atmosphere prior to the onset of radio-galaxy activity. Motivated by the very high metalicity of the SW ridge, we hypothesize that the ICM asymmetry was caused by the extremely rapid stripping of metal enriched gas from a starburst galaxy that plunged through the core of A4059. Furthermore, we suggest that the onset of powerful radio-galaxy activity in the cD galaxy may have been initiated by this starburst/stripping event, either via the tidal-shocking of cold gas native to the cD galaxy, or the accretion of cold gas that had been stripped from the starburst galaxy.Comment: Accepted for publication in the Astrophysical Journal. 12 pages, 11 figures. A version of this paper including full resolution figures can be found at http://www.astro.umd.edu/~chris/publications/papers/a4059_2008.pd

Indonesia at home and abroad: economics, politics and security

Overview: This inaugural suite of papers for the National Security College Issue Brief Series is also a component of an NSC research grant investigating the prospects, challenges and opportunities associated with Indonesia’s ascent in the political-security, economic, and socio-cultural spheres. The chief investigators for this project are Dr Christopher Roberts, Dr Ahmad Habir, and Associate Professor Leonard Sebastian. These issue briefs represent a short precursor to a fi fteen chapter edited book, titled Indonesia’s Ascent: Power, Leadership and the Regional Order, to be published by Palgrave MacMillan in late 2014. The project also involved conferences and fi eldwork in both Canberra and Jakarta between 2012 and 2013

Contract-Based General-Purpose GPU Programming

Using GPUs as general-purpose processors has revolutionized parallel computing by offering, for a large and growing set of algorithms, massive data-parallelization on desktop machines. An obstacle to widespread adoption, however, is the difficulty of programming them and the low-level control of the hardware required to achieve good performance. This paper suggests a programming library, SafeGPU, that aims at striking a balance between programmer productivity and performance, by making GPU data-parallel operations accessible from within a classical object-oriented programming language. The solution is integrated with the design-by-contract approach, which increases confidence in functional program correctness by embedding executable program specifications into the program text. We show that our library leads to modular and maintainable code that is accessible to GPGPU non-experts, while providing performance that is comparable with hand-written CUDA code. Furthermore, runtime contract checking turns out to be feasible, as the contracts can be executed on the GPU