A Naturally Minute Quantum Correction to the Cosmological Constant Descended from the Hierarchy

We demonstrate that an extremely small but positive quantum correction, or the Casimir energy, to the cosmological constant can arise from a massive bulk fermion field in the Randall-Sundrum model. Specifically, a cosmological constant doubly descended from the Planck-electroweak hierarchy and as minute as the observed dark energy scale can be naturally achieved without fine-tuning of the bulk fermion mass. To ensure the stabilization of the system, we discuss two stabilization mechanisms under this setup. It is found that the Goldberger-Wise mechanism can be successfully introduced in the presence of a massive bulk fermion, without spoiling the smallness of the quantum correction.Comment: 5 page

Predicting the ‘Unpredictable’ General Anti-Avoidance Rule (GAAR) in EU Tax Law

General Anti-Avoidance Rule (GAAR) is a type of rule designed to combat the tax-avoidance scenarios that in a legal form lawfully but aims to circumvent the legal consequences. GAAR is necessary for a tax system to address unexpected innovative tax avoidance scenarios. In the field of tax law, GAAR has been criticized for being too abstract and thus harmful to legal certainty. In the context of EU integration, the concept of GAAR has been developed and elaborated by Court of Justice of European Union as well as secondary laws, but there are quite a few different formulations. In the existing literature, it is established that, there are the subject test and the objective test cumulatively in the GAAR, which examines the taxpayers’ subjective intension and the objective economic reality. As to the relation between these two tests, scholars have established the theory that, the formulation and the context of the subjective test is actually influenced by the tax rule involved (that is, the purpose of the norm being circumvented). This paper will revisit GAARs in the EU tax law and present that, the theory of GAAR based on the purpose of the violated tax norm is indeed supported by latest case law of CJEU as well new Directives. Furthermore, the intention of the norm reconciles the subject test and the objective test. In this regard, the unpredictability of ‘GAAR’ actually has become more predictable

Preliminary Axial Flow Turbine Design and Off-Design Performance Analysis Methods for Rotary Wing Aircraft Engines

For the preliminary design and the off-design performance analysis of axial flow turbines, a pair of intermediate level-of-fidelity computer codes, TD2-2 (design; reference 1) and AXOD (off-design; reference 2), are being evaluated for use in turbine design and performance prediction of the modern high performance aircraft engines. TD2-2 employs a streamline curvature method for design, while AXOD approaches the flow analysis with an equal radius-height domain decomposition strategy. Both methods resolve only the flows in the annulus region while modeling the impact introduced by the blade rows. The mathematical formulations and derivations involved in both methods are documented in references 3, 4 for TD2-2) and in reference 5 (for AXOD). The focus of this paper is to discuss the fundamental issues of applicability and compatibility of the two codes as a pair of companion pieces, to perform preliminary design and off-design analysis for modern aircraft engine turbines. Two validation cases for the design and the off-design prediction using TD2-2 and AXOD conducted on two existing high efficiency turbines, developed and tested in the NASA/GE Energy Efficient Engine (GE-E3) Program, the High Pressure Turbine (HPT; two stages, air cooled) and the Low Pressure Turbine (LPT; five stages, un-cooled), are provided in support of the analysis and discussion presented in this paper

Capability Extension to the Turbine Off-Design Computer Program AXOD With Applications to the Highly Loaded Fan-Drive Turbines

The axial flow turbine off-design computer program AXOD has been upgraded to include the outlet guide vane (OGV) into its acceptable turbine configurations. The mathematical bases and the techniques used for the code implementation are described and discussed in lengths in this paper. This extended capability is verified and validated with two cases of highly loaded fan-drive turbines, designed and tested in the V/STOL Program of NASA. The first case is a 4 1/2-stage turbine with an average stage loading factor of 4.66, designed by Pratt & Whitney Aircraft. The second case is a 3 1/2-stage turbine with an average loading factor of 4.0, designed in-house by the NASA Lewis Research Center (now the NASA Glenn Research Center). Both cases were experimentally tested in the turbine facility located at the Glenn Research Center. The processes conducted in these studies are described in detail in this paper, and the results in comparison with the experimental data are presented and discussed. The comparisons between the AXOD results and the experimental data are in excellent agreement

A Guide to Axial-Flow Turbine Off-Design Computer Program AXOD2

A Users Guide for the axial flow turbine off-design computer program AXOD2 is composed in this paper. This Users Guide is supplementary to the original Users Manual of AXOD. Three notable contributions of AXOD2 to its predecessor AXOD, both in the context of the Guide or in the functionality of the code, are described and discussed in length. These are: 1) a rational representation of the mathematical principles applied, with concise descriptions of the formulas implemented in the actual coding. Their physical implications are addressed; 2) the creation and documentation of an Addendum Listing of input namelist-parameters unique to AXOD2, that differ from or are in addition to the original input-namelists given in the Manual of AXOD. Their usages are discussed; and 3) the institution of proper stoppages of the code execution, encoding termination messaging and error messages of the execution to AXOD2. These measures are to safe-guard the integrity of the code execution, such that a failure mode encountered during a case-study would not plunge the code execution into indefinite loop, or cause a blow-out of the program execution. Details on these are discussed and illustrated in this paper. Moreover, this computer program has since been reconstructed substantially. Standard FORTRAN Langue was instituted, and the code was formatted in Double Precision (REAL*8). As the result, the code is now suited for use in a local Desktop Computer Environment, is perfectly portable to any Operating System, and can be executed by any FORTRAN compiler equivalent to a FORTRAN 9095 compiler. AXOD2 will be available through NASA Glenn Research Center (GRC) Software Repository

Geometric phase and quantum phase transition in an inhomogeneous periodic XY spin-1/2 model

The notion of geometric phase has been recently introduced to analyze the quantum phase transitions of many-body systems from the geometrical perspective. In this work, we study the geometric phase of the ground state for an inhomogeneous period-two anisotropic XY model in a transverse field. This model encompasses a group of familiar spin models as its special cases and shows a richer critical behavior. The exact solution is obtained by mapping on a fermionic system through the Jordan-Wigner transformation and constructing the relevant canonical transformation to realize the diagonalization of the Hamiltonian coupled in the $k$-space. The results show that there may exist more than one quantum phase transition point at some parameter regions and these transition points correspond to the divergence or extremum properties of the Berry curvature.Comment: 6 pages, 3 figures. As a backup of a previous work and some typos in the published version are fixe

Threshold Effects in the Decay of Heavy b' and t' Quarks

A sequential fourth generation is still viable, but the t' and b' quarks are constrained to be not too far apart in mass. The t'{\to}bW and b'{\to}tW decay channels are still being pursued at the Tevatron, which would soon be surpassed by the LHC. We use a convolution method with up to five-body final state to study t' and b' decays. We show how the two decay branches for m_{b'} below the tW threshold, b'{\to}tW^* and t^*W, merge with b'{\to}tW above the threshold. We then consider the heavy-to-heavy transitions b'{\to}t^{\prime(*)}W^{(*)} (or t'{\to}b^{\prime(*)}W^{(*)}), as they are not suppressed by quark mixing. We find that, because of the threshold sensitivity of the branching fraction of t'{\to}b'W^* (or b'{\to}t'W^*), it is possible to measure the strength of the CKM mixing element V_{t'b} (or V_{tb'}), especially when it is rather small. We urge the experiments to pursue and separate the t'{\to}b'W^* (or b'{\to}t'W^*) decay in their search program

SED-inferred properties and morphology of Lyman-break galaxies at z∼1z\sim 1 in the CDF-S

After carefully cross-identifying a previously discovered GALEX-selected Lyman Break Galaxy (LBG) candidates one-to-one with their optical counterparts in the field of the CDF-S, we re-estimate their photometric redshifts using multi-wavelength data from UV, optical to NIR. We refine a new updated sample of 383 LBGs at 0.7\la z \la 1.4. Most LBGs are classified as starburst and irregular types. Ages spread from several Myr to 1.5Gyr. Their dust-corrected star formation rates (SFRs) and stellar masses ($M_*$) are from 4\my to 220\my and from 2.3\times 10^8 \msun to 4 \times 10^{11} \msun. The rest-frame FUV luminosity function of LBGs are presented. LBGs of irregular types mainly distribute along the "main sequence" of star forming galaxies while most LBGs of starburst types locate in the starburst region. A "downsizing" effect is clearly found and LBGs distribute in the "blue" cloud. HST images in F606W ($V$ band) and F850LP ($z$ band) are taken from the GEMS and GOODS-S surveys. SExtractor and GALFIT are applied to get their morphological parameters. A morphological sample of 142 LBGs with reliable results of \sersic and sizes in both bands is defined. We find that LBGs at $z\sim 1$ are dominated by disk-like galaxies. Correlations between photometric and morphological properties of LBGs are investigated. Strong correlations between their half-light radii and $M_*$, i.e., size-stellar mass relations, are found in both bands. Physical connections between correlations and the "downsizing" effect are discussed.Comment: 26 pages, 30 figures, 6 tables, accepted by MNRA