Halite and stable chlorine isotopes in the Zag H3-6 breccia

Zag is an H3-6 chondrite regolith breccia within which we have studied 14 halite grains ?3mm. The purity of the associated NaCl-H2O brine is implied by freezing characteristics of fluid inclusions in the halite and EPMA analyses together with a lack of other evaporite-like phases in the Zag H3-6 component. This is inconsistent with multistage evolution of the fluid involving scavenging of cations in the Zag region of the parent body. We suggest that the halite grains are clastic and did not crystallise in situ. Halite and water-soluble extracts from Zag have light Cl isotopic compositions, ?37-Cl = -1.4 to '2.8 �. Previously reported bulk carbonaceous chondrite values are approximately ?37-Cl = +3 to +4 �. This difference is too great to be the result of fractionation during evaporation and instead we suggest that Cl isotopes in chondrites are fractionated between a light reservoir associated with fluids and a heavier reservoir associated with higher temperature phases such as phosphates and silicates. Extraterrestrial carbon released at 600 degrees Celsius from the H3-4 matrix has ?13-C = -20 �, consistent with poorly graphitised material being introduced into the matrix rather than indigenous carbonate derived from a brine. We have also examined 28 other H-chondrite falls in order to ascertain how widespread halite or evaporite-like mineral assemblages are in ordinary chondrites. We did not find any more to add to Zag (H3-6) and Monahans (H5), which suggests that such highly soluble phases were not usually preserved on the parent bodies

Spin dependent D-brane interactions and scattering amplitudes in matrix theory

Spin interactions beteween two moving Dp-branes are analyzed using the Green-Schwarz formalism of boundary states. This approach turns out to be extremely efficient to compute all the spin effects related by supersymmetry to the leading v^4/r^7-p term. All these terms are shown to be scale invariant, supporting a matrix model description of supergravity interactions. By employing the LSZ reduction formula for matrix theory and the mentioned supersymmetric effective potential for D0-branes, we compute the t-pole of graviton-graviton and three form-three form scattering in matrix theory. The results are found to be in complete agreement with tree level supergravity in the corresponding kinematical regime and provide, moreover, an explicit map between these degrees of freedom in both theories.Comment: 8 pages, no figures, talk presented at the conference "Quantum aspects of gauge theories, supergravity and unification", Corfu, Greece, to appear in the proceeding

Decoupling of Degenerate Positive-norm States in Witten's String Field Theory

We show that the degenerate positive-norm physical propagating fields of the open bosonic string can be gauged to the higher rank fields at the same mass level. As a result, their scattering amplitudes can be determined from those of the higher spin fields. This phenomenon arises from the existence of two types of zero-norm states with the same Young representations as those of the degenerate positive-norm states in the old covariant first quantized (OCFQ) spectrum. This is demonstrated by using the lowest order gauge transformation of Witten's string field theory (WSFT) up to the fourth massive level (spin-five), and is found to be consistent with conformal field theory calculation based on the first quantized generalized sigma-model approach. In particular, on-shell conditions of zero-norm states in OCFQ stringy gauge transformation are found to correspond, in a one-to-one manner, to the background ghost fields in off-shell gauge transformation of WSFT. The implication of decoupling of scalar modes on Sen's conjectures was also briefly discussed.Comment: 18 pages, use Latex with revtex

Small eigenvalues of the SU(3) Dirac operator on the lattice and in Random Matrix Theory

We have calculated complete spectra of the staggered Dirac operator on the lattice in quenched SU(3) gauge theory for \beta = 5.4 and various lattice sizes. The microscopic spectral density, the distribution of the smallest eigenvalue, and the two-point spectral correlation function are analyzed. We find the expected agreement of the lattice data with universal predictions of the chiral unitary ensemble of random matrix theory up to a certain energy scale, the Thouless energy. The deviations from the universal predictions are determined using the disconnected scalar susceptibility. We find that the Thouless energy scales with the lattice size as expected from theoretical arguments making use of the Gell-Mann--Oakes--Renner relation.Comment: REVTeX, 5 pages, 4 figure

A condensed matter interpretation of SM fermions and gauge fields

We present the bundle Aff(3) x C x /(R^3), with a geometric Dirac equation on it, as a three-dimensional geometric interpretation of the SM fermions. Each C x /(R^3) describes an electroweak doublet. The Dirac equation has a doubler-free staggered spatial discretization on the lattice space Aff(3) x C (Z^3). This space allows a simple physical interpretation as a phase space of a lattice of cells in R^3. We find the SM SU(3)_c x SU(2)_L x U(1)_Y action on Aff(3) x C x /(R^3) to be a maximal anomaly-free special gauge action preserving E(3) symmetry and symplectic structure, which can be constructed using two simple types of gauge-like lattice fields: Wilson gauge fields and correction terms for lattice deformations. The lattice fermion fields we propose to quantize as low energy states of a canonical quantum theory with Z_2-degenerated vacuum state. We construct anticommuting fermion operators for the resulting Z_2-valued (spin) field theory. A metric theory of gravity compatible with this model is presented too.Comment: Minimal modifications in comparison with the published versio

Open Heterotic Strings

We classify potential cosmic strings according to the topological charge measurable outside the string core. We conjecture that in string theory it is this charge that governs the stability of long strings. This would imply that the SO(32) heterotic string can have endpoints, but not the E_8 x E_8 heterotic string. We give various arguments in support of this conclusion.Comment: 15 pages. v.2: typos, references correcte

Non-transitive maps in phase synchronization

Concepts from the Ergodic Theory are used to describe the existence of non-transitive maps in attractors of phase synchronous chaotic systems. It is shown that for a class of phase-coherent systems, e.g. the sinusoidally forced Chua's circuit and two coupled R{\"o}ssler oscillators, phase synchronization implies that such maps exist. These ideas are also extended to other coupled chaotic systems. In addition, a phase for a chaotic attractor is defined from the tangent vector of the flow. Finally, it is discussed how these maps can be used to real time detection of phase synchronization in experimental systems

On the consistency of de Sitter vacua

In this paper the consistency of the de Sitter invariant $\alpha$-vacua, which have been introduced as simple tools to study the effects of transplanckian physics, is investigated. In particular possible non renormalization problems are discussed, as well as non standard properties of Greens functions. We also discuss the non thermal properties of the $\alpha$-vacua and the necessity of $\alpha$ to change. The conclusion is that non of these problems necessarily exclude an application of the $\alpha$-vacua to inflation.Comment: 12 pages, v2: minor clarifications and corrections to reference

An Automatic Invisible Axion In The SUSY Preon Model

It is shown that the recently proposed preon model which provides a unified origin of the diverse mass scale and an explanation of family replication as well as of inter-family mass-hierarchy, possesses a Peccei-Quinn symmetry whose spontaneous breaking leads to an automatic invisible axion. Existence of the PQ-symmetry is simply a consequence of supersymmetry and requirement of minimality in the field-content and interactions, which propose that the lagrangian should possess only those terms which are dictated by the gauge principle and no others. In addition to the axion, the model also generates two superlight Goldstone bosons and their superpartners which are cosmologically safe.Comment: (TeX file) 16 Page