1,859 research outputs found
Early differentiation of the Moon: Experimental and modeling studies
Major accomplishments include the mapping out of liquidus boundaries of lunar and meteoritic basalts at low pressure; the refinement of computer models that simulate low pressure fractional crystallization; the development of a computer model to calculate high pressure partial melting of the lunar and Martian interiors; and the proposal of a hypothesis of early lunar differentiation based upon terrestrial analogs
Workshop on Pristine Highlands Rocks and the early History of the Moon
Oxide composition of the Moon, evidence for an initially totally molten Moon, geophysical contraints on lunar composition, random sampling of a layered intrusion, lunar highland rocks, early evolution of the Moon, mineralogy and petrology of the pristine rocks, relationship of the pristine nonmore rocks to the highlands soils and breccias, ferroan anorthositic norite, early lunar igneous history, compositional variation in ferroan anosthosites, a lunar magma ocean, deposits of lunar pristine rocks, lunar and planetary compositions and early fractionation in the solar nebula, Moon composition models, petrogenesis in a Moon with a chondritic refractory lithophile pattern, a terrestrial analog of lunar ilmenite bearing camulates, and the lunar magma ocean are summarized
Classical and quantum interference in multiband optical Bloch oscillations
Classical and quantum interference of light propagating in arrays of coupled
waveguides and undergoing multiband optical Bloch oscillations (BOs) with
negligible Zener tunneling is theoretically investigated. In particular, it is
shown that Mach-Zehnder-like interference effects spontaneously arise in
multiband BOs owing to beam splitting and subsequent beam recombination
occurring in one BO cycle. As a noteworthy example of quantum interference, we
discuss the doubling of interference fringes in photon counting rates for a
correlated photon pair undergoing two-band BOs, a phenomenon analogous to the
manifestation of the de Broglie wavelength of an entangled biphoton state
observed in quantum Mach-Zehnder interferometry.Comment: 11 pages, 4 figure
Optical realization of relativistic non-Hermitian quantum mechanics
Light propagation in distributed feedback optical structures with gain/loss
regions is shown to provide an accessible laboratory tool to visualize in
optics the spectral properties of the one-dimensional Dirac equation with
non-Hermitian interactions. Spectral singularities and PT symmetry breaking of
the Dirac Hamiltonian are shown to correspond to simple observable physical
quantities and related to well-known physical phenomena like resonance
narrowing and laser oscillation.Comment: 4 page
Experimental petrology and origin of Fra Mauro rocks and soil
Melting experiments over the pressure range 0 to 20 kilobars were conducted on Apollo 14 igneous rocks 14310 and 14072 and on comprehensive fines 14259. The mineralogy and textures of rocks 14310 and 14072 are presumed to be the result of near-surface crystallization. The chemical compositions of the samples show special relationships to multiply-saturated liquids in the system: anorthite-forsterite-fayalite-silica at low pressure. Partial melting of a lunar crust consisting largely of plagioclase, low calcium pyroxene, and olivine, followed by crystal fractionation at the lunar surface is proposed as a mechanism for the production of the igneous rocks and soil glasses sampled by Apollo 14
Optical Zener-Bloch oscillations in binary waveguide arrays
Zener tunneling in a binary array of coupled optical waveguides with
transverse index gradient is shown to produce a sequence of regular or
irregular beam splitting and beam recombination events superimposed to Bloch
oscillations. These periodic or aperiodic Zener-Bloch oscillations provide a
clear and visualizable signature in an optical system of coherent multiband
dynamics encountered in solid-state or matter-wave system
Space-time Vector Supersymmetry and Massive Spinning Particle
We construct the action of a relativistic spinning particle from a non-linear
realization of a space-time odd vector extension of the Poincar\'e group. For
particular values of the parameters appearing in the lagrangian the model has a
gauge world-line supersymmetry.{As a consequence of this local symmetry there
are BPS solutions in the model preserving 1/5 of the supersymmetries.} A
supersymmetric invariant quantization produces two decoupled 4d Dirac
equations.Comment: 14 pages. Few references and two comments adde
Stability of the self-phase-locked pump-enhanced singly resonant parametric oscillator
Steady-state and dynamics of the self-phase-locked (3\omega ==> 2\omega,
\omega) subharmonic optical parametric oscillator are analyzed in the
pump-and-signal resonant configuration, using an approximate analytical model
and a full propagation model. The upper branch solutions are found always
stable, regardless of the degree of pump enhancement. The domain of existence
of stationary states is found to critically depend on the phase-mismatch of the
competing second-harmonic process.Comment: LateX2e/RevteX4, 4 pages, 5 figures. Submitted to Phys. Rev. A
(accepted on Jan. 17, 2003
Discrete diffraction and shape-invariant beams in optical waveguide arrays
General properties of linear propagation of discretized light in homogeneous
and curved waveguide arrays are comprehensively investigated and compared to
those of paraxial diffraction in continuous media. In particular, general laws
describing beam spreading, beam decay and discrete far-field patterns in
homogeneous arrays are derived using the method of moments and the steepest
descend method. In curved arrays, the method of moments is extended to describe
evolution of global beam parameters. A family of beams which propagate in
curved arrays maintaining their functional shape -referred to as discrete
Bessel beams- is also introduced. Propagation of discrete Bessel beams in
waveguide arrays is simply described by the evolution of a complex
parameter similar to the complex parameter used for Gaussian beams in
continuous lensguide media. A few applications of the parameter formalism
are discussed, including beam collimation and polygonal optical Bloch
oscillations. \Comment: 14 pages, 5 figure
Chaotic ray dynamics in an optical cavity with a beam splitter
We investigate the ray dynamics in an optical cavity when a ray splitting
mechanism is present. The cavity is a conventional two-mirror stable resonator
and the ray splitting is achieved by inserting an optical beam splitter
perpendicular to the cavity axis. Using Hamiltonian optics, we show that such a
simple device presents a surprisingly rich chaotic ray dynamics.Comment: 6 pages, 4 figure
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