Quantum Maxwell-Bloch equations for spatially inhomogeneous semiconductor lasers

We present quantum Maxwell-Bloch equations (QMBE) for spatially inhomogeneous semiconductor laser devices. The QMBE are derived from fully quantum mechanical operator dynamics describing the interaction of the light field with the quantum states of the electrons and the holes near the band gap. By taking into account field-field correlations and field-dipole correlations, the QMBE include quantum noise effects which cause spontaneous emission and amplified spontaneous emission. In particular, the source of spontaneous emission is obtained by factorizing the dipole-dipole correlations into a product of electron and hole densities. The QMBE are formulated for general devices, for edge emitting lasers and for vertical cavity surface emitting lasers, providing a starting point for the detailed analysis of spatial coherence in the near field and far field patterns of such laser diodes. Analytical expressions are given for the spectra of gain and spontaneous emission described by the QMBE. These results are applied to the case of a broad area laser, for which the frequency and carrier density dependent spontaneous emission factor beta and the evolution of the far field pattern near threshold are derived.Comment: 22 pages RevTex and 7 figures, submitted to Phys.Rev.A, revisions in abstract and in the discussion of temporal coherenc

Building versus maintaining a perceived confidence-based tax climate: experimental evidence

A confidence-based climate between public administrations and citizens is essential. This paper argues and provides empirical evidence that depending on the perceived interaction history, different policies are needed to build versus maintain confidence. Applying the extended Slippery Slope Framework of tax compliance, an online and a laboratory experiment were conducted to explore whether tax authorities’ coercive and legitimate power have different effects depending on whether they are situated in an antagonism-based or confidence-based climate. Results showed that in an antagonism-based interaction climate, a combination of high coercive and high legitimate power changed the climate into a confidence-based interaction climate. In contrast, in a confidence-based climate the same power combination did not maintain but erode the climate. Results also suggest that confidence-based climates are maintained by low coercive power combined with high legitimate power. The paper concludes that interaction climates operate as psychological frames which guide how policy instruments affect taxpayers’ trust in the tax authorities.Social decision makin

Geochemistry and mineralogy of the phonolite lava lake, Erebus volcano, Antarctica: 1972–2004 and comparison with older lavas

Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Volcanology and Geothermal Research 177 (2008): 589-605, doi:10.1016/j.jvolgeores.2007.11.025.Mount Erebus, Antarctica, is a large (3794 m) alkaline open-conduit stratovolcano that hosts a vigorously convecting and persistently degassing lake of anorthoclase phonolite magma. The composition of the lake was investigated by analyzing glass and mineral compositions in lava bombs erupted between 1972 and 2004. Matrix glass, titanomagnetite, olivine, clinopyroxene, and fluor-apatite compositions are invariant and show that the magmatic temperature (~1000°C) and oxygen fugacity (ΔlogFMQ = -0.9) have been stable. Large temperature variations at the lake surface (ca. 400 - 500°C) are not reflected in mineral compositions. Anorthoclase phenocrysts up to 10 cm in length feature a restricted compositional range (An10.3-22.9Ab62.8-68.1Or11.4-27.2) with complex textural and compositional zoning. Anorthoclase textures and compositions indicate crystallization occurs at low degrees of effective undercooling. We propose shallow water exsolution causes crystallization to occur and shallow convection repeats this process multiple times, yielding extremely large anorthoclase crystals. Minor variations in eruptive activity from 1972 to 2004 are decoupled from magma compositions. The variations probably relate to changes in conduit geometry within the volcano and/or variable input of CO2-rich volatiles into the upper-level magma chamber from deeper in the system. Eleven bulk samples of phonolite lava from the summit plateau that range in age from 0 ± 4 ka to 17 ± 8 ka were analyzed for major and trace elements. Small compositional variations are controlled by anorthoclase content. The lavas are indistinguishable from modern bulk lava bomb compositions and demonstrate that Erebus volcano has been erupting lava and tephra from the summit region with the same bulk composition for ~17 ka.The work at Erebus volcano and the continued operation of the Mount Erebus Volcano Observatory is supported by grants (OPP-0229305, ANT-0538414) from the Office of Polar Programs, National Science Foundation

Track A Basic Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd