Analysis of multiple, embedded gauge measurements of large-amplitude plane waves is addressed. Although many of the developments are general, the emphasis is on the determination of stress and density fields from particle velocity measurements. Practical considerations for embedded particle velocity and stress gauge measurements are discussed. Difficulties with existing analysis methods are described. The use of wave similarity as a criterion for determining the preferred analytic approach is emphasized. Simple waves are easily analyzed using the approaches suggested by Fowles, Cowperthwaite, and Williams J. Appl. Phys. 41, 360 (1970); 42, 456 (1971)]. Nonsimple waves, of broader interest, are best analyzed using surfaces explicitly fit to measured histories and directly integrating the conservation equations. Analytic and numerical examples of the surface-fitting procedure are presented. Uniqueness and verification of calculated results in past and present work are discussed.

No abstract

No abstract

The electron density‐functional formalism is used to compute first‐principles equations of state and charge distributions for the B1 and B2 phases of NaCl. The B1 equation of state is in excellent agreement with available static, acoustic, and shock wave data. The theoretical B2 equation of state differs significantly from available diamond anvil data but agrees well with shock wave data. Analysis of the theoretical and experimental isotherms suggest that the former may be a little low in pressure, while the latter is almost certainly too stiff. The computed charge distribution and valence band energies indicate that Cl‐Cl interaction may dominate the energetics of the B2 phase and that, consequently, the Cl ions are significantly distorted. The theoretical zero pressure Cl radius is smaller than the classical crystallographical radius, is sensitive to coordination, and expands significantly across the B1–B2 transformation. In contrast, the Na ion is insensitive to coordination and seems to retain classical ionic properties (+1 charge, spherical charge distribution) up to the highest pressures investigated (∼70 GPa). These properties are largely responsible for the failure of Born‐Mayer‐type structure independent pair potentials to account accurately for the changes in elastic properties of NaCl across the B1–B2 transformation.

We lay the foundation for a benchmarking methodology for assessing current and future quantum computers. We pose and begin addressing fundamental questions about how to fairly compare computational devices at vastly different stages of technological maturity. We critically evaluate and offer our own contributions to current quantum benchmarking efforts, in particular those involving adiabatic quantum computation and the Adiabatic Quantum Optimizers produced by D-Wave Systems, Inc. We find that the performance of D-Wave's Adiabatic Quantum Optimizers scales roughly on par with classical approaches for some hard combinatorial optimization problems; however, architectural limitations of D-Wave devices present a significant hurdle in evaluating real-world applications. In addition to identifying and isolating such limitations, we develop algorithmic tools for circumventing these limitations on future D-Wave devices, assuming they continue to grow and mature at an exponential rate for the next several years.