Local, bulk response functions, e.g. permittivity, and the macroscopic Maxwell equations completely specify the classical electromagnetic problem, which features only wavelength λ and geometric scales. The above neglect of intrinsic electronic length scales L e leads to an eventual breakdown in the nanoscopic limit. Here, we present a general theoretical and experimental framework for treating nanoscale electromagnetic phenomena. The framework features surface-response functions-known as the Feibelman d-parameters-which reintroduce the missing electronic length scales. As a part of our framework, we establish an experimental procedure to measure these complex, dispersive surface response functions, enabled by quasi-normal-mode perturbation theory and observations of pronounced nonclassical effects-spectral shifts in excess of 30% and the breakdown of Kreibig-like broadening-in a quintessential multiscale architecture: film-coupled nanoresonators, with feature-sizes comparable to both L e and λ.

We present a classifier to predict contextual polarity of subjective phrases in a sentence. Our approach features lexical scoring derived from the Dictionary of Affect in Language (DAL) and extended through WordNet, allowing us to automatically score the vast majority of words in our input avoiding the need for manual labeling. We augment lexical scoring with n-gram analysis to capture the effect of context. We combine DAL scores with syntactic constituents and then extract ngrams of constituents from all sentences. We also use the polarity of all syntactic constituents within the sentence as features. Our results show significant improvement over a majority class baseline as well as a more difficult baseline consisting of lexical n-grams.

Low-dimensional systems with sharp features in the density of states have been proposed as a means to improving the efficiency of thermoelectric devices. Quantum dot systems, which offer the sharpest density of states achievable, however, suffer from low power outputs while bulk (3-D) thermoelectrics, while displaying high power outputs, offer very low efficiencies. Here, we analyze the use of a resonant tunneling diode structure that combines the best of both aspects, that is, density of states distortion with a finite bandwidth due to confinement that aids the efficiency and a large number of current carrying transverse modes that enhances the total power output. We show that this device can achieve a high power output (∼ 0.3 MW/m 2 ) at efficiencies of ∼ 40% of the Carnot efficiency due to the contribution from these transverse momentum states at a finite bandwidth of kT /2. We then provide a detailed analysis of the physics of charge and heat transport with insights on parasitic currents that reduce the efficiency. Finally, a comparison between the resonant tunneling diode and a quantum dot device with comparable bandwidth reveals that a similar performance requires ultra-dense areal quantum dot densities of ∼ 10 12 /cm 2 .

We demonstrate saturated internal detection efficiency at 1550 nm wavelengths for meander-shaped superconducting nanowire single-photon detectors made of 3 nm thick MoSi films with widths of 1 and 3 µm, and active areas up to 400 by 400 µm 2 . Despite hairpin turns and a large number of squares (up to 10 4 ) in the device, the dark count rate was measured to be ∼10 3 cps at 99% of the switching current. This value is about two orders of magnitude lower than results reported recently for short MoSi devices with shunt resistors. We also found that 5 nm thick MoSi detectors with the same geometry were insensitive to single near-infrared photons, which may be associated with different levels of suppression of the superconducting order parameter. However, our results obtained on 3 nm thick MoSi devices are in a good agreement with predictions in the frame of a kinetic-equation approach.