Some Weyl modules of the algebraic groups of type E6E_6

Let $G$ be a simple algebraic group of type $E_6$ over an algebraically closed field of characteristic $p>0$. We determine the submodule structure of the Weyl modul es with highest weight $r\omega_1$ for $0\leq r\leq p-1$, where $\omega_1$ is the fundamental weight of the standard $27$-dimensional module. In the process, the structures of other Weyl modules with highest weights linked to $r\omega_1$ are also found. %We also give some computations for the Weyl modules with highest weights %of the form $r(\omega_1+\omega_6)$, which arise in the study of %the graph automorphism and associated twisted finite groups.Comment: 25 page

Study of large adaptive arrays for space technology applications

The research in large adaptive antenna arrays for space technology applications is reported. Specifically two tasks were considered. The first was a system design study for accurate determination of the positions and the frequencies of sources radiating from the earth's surface that could be used for the rapid location of people or vehicles in distress. This system design study led to a nonrigid array about 8 km in size with means for locating the array element positions, receiving signals from the earth and determining the source locations and frequencies of the transmitting sources. It is concluded that this system design is feasible, and satisfies the desired objectives. The second task was an experiment to determine the largest earthbound array which could simulate a spaceborne experiment. It was determined that an 800 ft array would perform indistinguishably in both locations and it is estimated that one several times larger also would serve satisfactorily. In addition the power density spectrum of the phase difference fluctuations across a large array was measured. It was found that the spectrum falls off approximately as f to the minus 5/2 power

Coherence freeze in an optical lattice investigated via pump-probe spectroscopy

Motivated by our observation of fast echo decay and a surprising coherence freeze, we have developed a pump-probe spectroscopy technique for vibrational states of ultracold $^{85}$Rb atoms in an optical lattice to gain information about the memory dynamics of the system. We use pump-probe spectroscopy to monitor the time-dependent changes of frequencies experienced by atoms and to characterize the probability distribution of these frequency trajectories. We show that the inferred distribution, unlike a naive microscopic model of the lattice, correctly predicts the main features of the observed echo decay.Comment: 4 pages, 5 figure

Experimental Investigation at M-20 of the Longitudinal Aerodynamic Characteristics, Pressure and Heat Transfer Distribution on a 50° Semivertex Angle Sphere-Cone

As part of continuing generalized overall space exploration studies, the Martin Company Space Exploration Group has been engaged in detailed study of the conceptual design of systems and configurations which ultimately would lead to development of a configuration suitable both for Mars atmosphere entry and landing an instrumented payload on the planet\u27s surface. A significant aspect of these Voyager Program Studies encompassed an experimental program devoted to obtaining detailed data concerning the aerodynamic characteristics, heat transfer, and pressure distributions on high-drag configurations at Mach numbers typical of atmospheric entry. One of our most comprehensive experimental efforts associated with the aerodynamics of atmospheric entry included investigations on a 50° semivertex angle sphere-cone equipped with varied afterbody shapes (Fig. 1 ). This configuration is the subject of this paper. It was specifically selected because it is representative of an applicable Voyager configuration and is a simple enough shape to permit comparison of the experimental results with those obtained by theoretical study. The facility utilized for these investigations was the Martin Company\u27s 25-in. Arc Heated Wind Tunnel 1 located at Middle River, Maryland. All the tests were conducted at a nominal Mach number of 20 in dry nitrogen, and data were obtained at environmental condi - tions which closely simulated portions of a typical deorbit trajectory of the Voyager Lander configuration as exemplified in Fig. 2. The trajectories superimposed on these plots are de-orbit mode trajectories into the Martian atmospheres commonly known as VM-7 and VM-8, which are based upon the Mariner N occultation experiment

Quantum Nonlocality in Two-Photon Experiments at Berkeley

We review some of our experiments performed over the past few years on two-photon interference. These include a test of Bell's inequalities, a study of the complementarity principle, an application of EPR correlations for dispersion-free time-measurements, and an experiment to demonstrate the superluminal nature of the tunneling process. The nonlocal character of the quantum world is brought out clearly by these experiments. As we explain, however, quantum nonlocality is not inconsistent with Einstein causality.Comment: 16 pages including 24 figure

Single polymer dynamics: coil-stretch transition in a random flow

By quantitative studies of statistics of polymer stretching in a random flow and of a flow field we demonstrate that the stretching of polymer molecules in a 3D random flow occurs rather sharply via the coil-stretch transition at the value of the criterion close to theoretically predicted.Comment: 4 pages, 5 figure

Coherent control of population transfer between vibrational states in an optical lattice via two-path quantum interference

We demonstrate coherent control of population transfer between vibrational states in an optical lattice by using interference between a one-phonon transition at $2\omega$ and a two-phonon transition at $\omega$. The $\omega$ and $2\omega$ transitions are driven by phase- and amplitude-modulation of the lattice laser beams, respectively. By varying the relative phase between these two pathways, we control the branching ratio of transitions to the first excited state and to the higher states. Our best result shows an improvement of the branching ratio by a factor of 3.5$\pm$0.7. Such quantum control techniques may find broad application in suppressing leakage errors in a variety of quantum information architectures.Comment: 5 pages, 4 figure

Densifying a Landfill for Commercial Development

This paper presents a case study of a dynamic compaction ( pounding ) project, undertaken in Skokie, Illinois. The purpose was to densify a 50-ft deep former municipal waste landfill for support of a one-story warehouse structure on shallow foundations. The majority of the pounding was performed utilizing a 15-ton weight falling from a height of 60 ft. In some areas, lower energy levels were used for surface compaction. All phases of the project are discussed, beginning with the subsurface exploration program and geotechnical analysis, through the experimental test pounding section, and the final check borings to observe that the production pounding was successful. A follow-up of the performance of the pounding, by monitoring foundation settlements, is discussed, as are topics such as depth of improvement, offsite vibrations, and energy input

Type 2 solar radio events observed in the interplanetary medium. Part 1: General characteristics

Twelve type 2 solar radio events were observed in the 2 MHz to 30 kHz frequency range by the radio astronomy experiment on the ISEE-3 satellite over the period from September 1978 to December 1979. These data provide the most comprehensive sample of type 2 radio bursts observed at kilometer wavelengths. Dynamic spectra of a number of events are presented. Where possible, the 12 events were associated with an initiating flare, ground based radio data, the passage of a shock at the spacecraft, and the sudden commencement of a geomagnetic storm. The general characteristics of kilometric type 2 bursts are discussed