Principles of Antifragile Software

The goal of this paper is to study and define the concept of "antifragile software". For this, I start from Taleb's statement that antifragile systems love errors, and discuss whether traditional software dependability fits into this class. The answer is somewhat negative, although adaptive fault tolerance is antifragile: the system learns something when an error happens, and always imrpoves. Automatic runtime bug fixing is changing the code in response to errors, fault injection in production means injecting errors in business critical software. I claim that both correspond to antifragility. Finally, I hypothesize that antifragile development processes are better at producing antifragile software systems.Comment: see https://refuses.github.io

Space Laser Power Transmission System Studies

Power transmission by laser technique is addressed. Space to Earth and space to space configurations are considered

Report of the Higgs Working Group of the Tevatron Run 2 SUSY/Higgs Workshop

This report presents the theoretical analysis relevant for Higgs physics at the upgraded Tevatron collider and documents the Higgs Working Group simulations to estimate the discovery reach in Run 2 for the Standard Model and MSSM Higgs bosons. Based on a simple detector simulation, we have determined the integrated luminosity necessary to discover the SM Higgs in the mass range 100-190 GeV. The first phase of the Run 2 Higgs search, with a total integrated luminosity of 2 fb-1 per detector, will provide a 95% CL exclusion sensitivity comparable to that expected at the end of the LEP2 run. With 10 fb-1 per detector, this exclusion will extend up to Higgs masses of 180 GeV, and a tantalizing 3 sigma effect will be visible if the Higgs mass lies below 125 GeV. With 25 fb-1 of integrated luminosity per detector, evidence for SM Higgs production at the 3 sigma level is possible for Higgs masses up to 180 GeV. However, the discovery reach is much less impressive for achieving a 5 sigma Higgs boson signal. Even with 30 fb-1 per detector, only Higgs bosons with masses up to about 130 GeV can be detected with 5 sigma significance. These results can also be re-interpreted in the MSSM framework and yield the required luminosities to discover at least one Higgs boson of the MSSM Higgs sector. With 5-10 fb-1 of data per detector, it will be possible to exclude at 95% CL nearly the entire MSSM Higgs parameter space, whereas 20-30 fb-1 is required to obtain a 5 sigma Higgs discovery over a significant portion of the parameter space. Moreover, in one interesting region of the MSSM parameter space (at large tan(beta)), the associated production of a Higgs boson and a b b-bar pair is significantly enhanced and provides potential for discovering a non-SM-like Higgs boson in Run 2.Comment: 185 pages, 124 figures, 55 table

Dynamical Quantum Phase Transitions in the Transverse Field Ising Model

A phase transition indicates a sudden change in the properties of a large system. For temperature-driven phase transitions this is related to non-analytic behavior of the free energy density at the critical temperature: The knowledge of the free energy density in one phase is insufficient to predict the properties of the other phase. In this paper we show that a close analogue of this behavior can occur in the real time evolution of quantum systems, namely non-analytic behavior at a critical time. We denote such behavior a dynamical phase transition and explore its properties in the transverse field Ising model. Specifically, we show that the equilibrium quantum phase transition and the dynamical phase transition in this model are intimately related.Comment: 4+4 pages, 4 figures, Appendix adde

Neutron activation analysis traces copper artifacts to geographical point of origin

Impurities remaining in the metallic copper are identified and quantified by spectrographic and neutron activation analysis. Determination of the type of ore used for the copper artifact places the geographic point of origin of the artifact

Late movement of basin-edge lobate scarps on Mercury

Basin-edge lobate scarps are a sub-type of tectonic shortening structure on the surface of Mercury that have formed at the edge of volcanic units that fill or partly fill impact basins. We have performed a global survey of these features and find that they are widespread in basins across the planet. We obtained model ages from crater size–frequency distribution analysis for a subset of our surveyed basins, for both the smooth plains infill and for the last resolvable tectonic activity on the associated basin-edge scarps. Our results indicate that some of these lobate scarps were still accumulating strain in the late Mansurian (approximately 1 Ga). From a photogeological assessment, we find that the orientations of these basin-edge lobate scarps are similar to those reported for the global population of lobate scarps in earlier studies, appearing to align ∼north–south at low latitudes and ∼east–west at higher latitudes. However, reassessing these landforms’ orientation with artificially illuminated topographic data does not allow us to rule out the effect of illumination bias. We propose that these landforms, the result of crustal shortening in response to global contraction, formed along the interface between the basin floor and the smooth plains unit, which acted as a mechanical discontinuity along which shortening strains were concentrated

Entropy and Entanglement in Quantum Ground States

We consider the relationship between correlations and entanglement in gapped quantum systems, with application to matrix product state representations. We prove that there exist gapped one-dimensional local Hamiltonians such that the entropy is exponentially large in the correlation length, and we present strong evidence supporting a conjecture that there exist such systems with arbitrarily large entropy. However, we then show that, under an assumption on the density of states which is believed to be satisfied by many physical systems such as the fractional quantum Hall effect, that an efficient matrix product state representation of the ground state exists in any dimension. Finally, we comment on the implications for numerical simulation.Comment: 7 pages, no figure

A Thin HI Circumnuclear Disk in NGC4261

We report on high sensitivity, spectral line VLBI observations of the HI absorption feature in the radio galaxy NGC4261. Although absorption is only detectable on the most sensitive baseline, it can be unambiguously associated with the counterjet and is interpreted to originate in a thin atomic circumnuclear disk. This structure is probably a continuation of the dusty accretion disk inferred from HST imaging, which could be feeding the massive black hole. HI column densities in front of the counterjet of the order of 10^{21}(T_sp/100 K) cm^{-2} are derived, consistent with X-ray data and VLBI scale free-free absorption. The data presented here are the result of the first scientific project processed on the new EVN MkIV data processor.Comment: 4 pages, 3 postscript figures, Astronomy and Astrophysics Letters, in pres