The notion of the weak value of a quantum mechanical observable has recently been introduced by Aharonov et al ., hereafter referred to as AAV. Their analysis led to the controversial result that the weak values for an observable can lie well outside its associated eigenvalue spectrum. We have performed an experiment similar to one proposed by Knight et al . and demonstrated that weak values can be observed and that they exhibit the properties described by AAV within the regime of validity defined by Duck et al . It is shown that these properties are produced by interference phenomena that result from the loss of 'welcher Weg' information. We have also identified an intrinsic 'weak energy' which appears in the equation of motion for the weak value of an observable and have shown that it can be non-vanishing only for systems which are both preselected and postselected. It is noted that such a 'weak spin-rotation coupling energy' can be associated with our experiment and that it is manifested in our experimental data. We suggest that preselection and postselection measurement techniques could be useful for the creation and study of physical phenomena that might be otherwise unobservable.

Order of magnitude estimates suggest that optically controlled bulk semiconductor switches should be able to withstand voltages up to the product of their thickness and the dielectric strength of their material. In reality, however, the devices fail -i.e., exhibit a behavior that resembles dielectric breakdown -already at voltages which are much lower. This deficiency threatens to limit the prospects of the device concept quite seriously and has so far not completely been understood. In our paper, we discuss several mechanisms which may underlie the observed phenomenon, and focus in particular on the dynamical aspects of it, namely on the sudden transition ("sudden breakdown" ) which takes the switch within a few ns from from the resistive off-state to a highly conductive on-state. We investigate a scenario that relates this transition to a second effect also seen during breakdown, namely to the spontaneous onset of current filamentation, and speculate that the magnetic self-contraction of the current (known as the "pinch effect") may play an essential role in the process. On the basis of a mathematical device model which incorporates the effects of particle transport and magnetic interaction, we obtain quantitative results for the speed and the threshold of magnetically driven filamentation, and find those numbers to lie in the A and the ps region, respectively. We conclude that the magnetic pinch may play a essential role in the dynamics of current filamentation and fast breakdown, but cannot explain the fast observed current rise in the ns-range by itself.

− Over the last few years, members of the electromagnetics community have used two types of models to investigate the differences in upset thresholds for multiple microsecond pulses compared to single or few shot short-pulse illuminations of complex electronic equipment. These models are: communication theory models and hybrid models. After reviewing and contrasting these models, we use a hybrid model to better understand failure modes in a SCADA trainer as a simple example. The model considers the type of failures seen in current injection testing of this SCADA. The purpose of the model is to introduce a methodology of predicting failure modes for complex infrastructure components.