Tectonic controls on residual oil saturation below the present-day fluid contact level in reservoirs of the Persian Gulf

Acknowledgments The authors would like to acknowledge, and gratefully appreciate the support of, the Aberdeen Formation Evaluation Society for their sponsorship, and Emerson (Paradigm) for providing the Geology software for the development of this study.Peer reviewedPostprin

Correlation induced phonon softening in low density coupled bilayer systems

We predict a possible phonon softening instability in strongly correlated coupled semiconductor bilayer systems. By studying the plasmon-phonon coupling in coupled bilayer structures, we find that the renormalized acoustic phonon frequency may be softened at a finite wave vector due to many-body local field corrections, particularly in low density systems where correlation effects are strong. We discuss experimental possibilities to search for this predicted phonon softening phenomenon.Comment: 4 pages with 2 figure

Many-body correlations probed by plasmon-enhanced drag measurements in double quantum well structures

Electron drag measurements of electron-electron scattering rates performed close to the Fermi temperature are reported. While evidence of an enhancement due to plasmons, as was recently predicted [K. Flensberg and B. Y.-K. Hu, Phys. Rev. Lett. 73, 3572 (1994)], is found, important differences with the random-phase approximation based calculations are observed. Although static correlation effects likely account for part of this difference, it is argued that correlation-induced multiparticle excitations must be included to account for the magnitude of the rates and observed density dependences.Comment: 4 pages, 3 figures, revtex Accepted in Phys. Rev.

Injection-dominated tokamak experiments at ORNL

Experiments on the Oak Ridge Tokamak (ORMAK) have demonstrated ion and electron heating and improvements in anti ..beta../sub T/, anti n/sub e/, and q(a/sub l/) with neutral beam injection. They have also emphasized the need for low impurity levels in injected plasmas and the advantages of co- as opposed to counterinjection. These results, together with the favorable confinement and impurity results obtained in the Impurity Study Experiment (ISX-A) are encouraging in terms of injection-dominated, high beta experiments planned for ISX-B. This device will use 3.0 MW of injection power to study beta limits, confinement, heating, and impurity control in noncircular cross-section plasmas

A microfabricated sensor for thin dielectric layers

We describe a sensor for the measurement of thin dielectric layers capable of operation in a variety of environments. The sensor is obtained by microfabricating a capacitor with interleaved aluminum fingers, exposed to the dielectric to be measured. In particular, the device can measure thin layers of solid frozen from a liquid or gaseous medium. Sensitivity to single atomic layers is achievable in many configurations and, by utilizing fast, high sensitivity capacitance read out in a feedback system onto environmental parameters, coatings of few layers can be dynamically maintained. We discuss the design, read out and calibration of several versions of the device optimized in different ways. We specifically dwell on the case in which atomically thin solid xenon layers are grown and stabilized, in cryogenic conditions, from a liquid xenon bath

Phases in Strongly Coupled Electronic Bilayer Liquids

The strongly correlated liquid state of a bilayer of charged particles has been studied via the HNC calculation of the two-body functions. We report the first time emergence of a series of structural phases, identified through the behavior of the two-body functions.Comment: 5 pages, RevTEX 3.0, 4 ps figures; Submitted to Phys. Rev. Let

Dynamic correlations in symmetric electron-electron and electron-hole bilayers

The ground-state behavior of the symmetric electron-electron and electron-hole bilayers is studied by including dynamic correlation effects within the quantum version of Singwi, Tosi, Land, and Sjolander (qSTLS) theory. The static pair-correlation functions, the local-field correction factors, and the ground-state energy are calculated over a wide range of carrier density and layer spacing. The possibility of a phase transition into a density-modulated ground state is also investigated. Results for both the electron-electron and electron-hole bilayers are compared with those of recent diffusion Monte Carlo (DMC) simulation studies. We find that the qSTLS results differ markedly from those of the conventional STLS approach and compare in the overall more favorably with the DMC predictions. An important result is that the qSTLS theory signals a phase transition from the liquid to the coupled Wigner crystal ground state, in both the electron-electron and electron-hole bilayers, below a critical density and in the close proximity of layers (d <~ r_sa_0^*), in qualitative agreement with the findings of the DMC simulations.Comment: 13 pages, 11 figures, 2 table

Plasmons in coupled bilayer structures

We calculate the collective charge density excitation dispersion and spectral weight in bilayer semiconductor structures {\it including effects of interlayer tunneling}. The out-of-phase plasmon mode (the ``acoustic'' plasmon) develops a long wavelength gap in the presence of tunneling with the gap being proportional to the square root (linear power) of the tunneling amplitude in the weak (strong) tunneling limit. The in-phase plasmon mode is qualitatively unaffected by tunneling. The predicted plasmon gap should be a useful tool for studying many-body effects.Comment: 10 pages, 6 figures. to appear in Phys. Rev. Let