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A novel algorithm is proposed for solving coupled Maxwell and Schrödinger equations relying on the use of a length gauge form of the coupling between an electromagnetic field and electrons. Numerical simulations using codes implemented with the proposed and conventional algorithms have been performed for a harmonic model of a nanoplate subjected to a pulsed laser field whose central frequency is close to the plasmon frequency. We verify that the proposed algorithm can reduce computational time almost by half as compared with the conventional method. Figure 4. Relative error « of the time-dependent probability density measured at y = 0, | c (y = 0, t)| 2 for an electron confined by a 1D harmonic oscillator potential. in 2002. His research interest is concerned with computational electromagnetics. 544 S. OHNUKI ET AL.

A novel hybrid approach to the dynamics of electron interacting with time-dependent electromagnetic fields, namely, the Maxwell-Schrödinger approach, has been employed to study a system of electron confined in single-and multi-well electrostatic potentials subjected to pulsed laser fields. A comparison of the results of simulation to those obtained by the conventional Maxwell-Newton approach has been made by calculating the time response of the current density and the time-evolution of the electric field at an observation point. The results obtained by these two distinct approaches agree very well for the singlewell potential while disagree qualitatively for the multi-well potential. This clearly demonstrates limitation of applicability of the conventional Maxwell-Newton scheme to study electron dynamics in electromagnetic fields. IndexTerms-FDTD method, Maxwell-Schrödinger equations, multi-physics simulation, tunneling effect.

Herein, we investigate the optical properties of quantum plasmonic metasurfaces composed of metallic nano-objects with subnanometer gaps according to the time-dependent density functional theory, a fully quantum mechanical approach. When the quantum and classical descriptions are compared, the transmission, reflection, and absorption rates of the metasurface exhibit substantial differences at shorter gap distances. The differences are caused by electron transport through the gaps of the nano-objects. The electron transport has profound influences for gap distances of ≲ 0.2 nm; that is, approximately equal to half of the distance found in conventional gap plasmonics in isolated systems, such as metallic nanodimers. Furthermore, it is shown that the electron transport makes the plasmon features of the metasurface unclear and produces broad spectral structures in the optical responses. In particular, the reflection response exhibits rapid attenuation as the gap distance decreases, while the absorption response extends over a wide spectral range. ASSOCIATED CONTENT Supporting InformationDetailed theoretical descriptions of 2D coarse graining approach, the TDDFT, and classical theory with plasmonic responses are given. This material is submitted as a separate file.

In this study, a third-order nonlinear optical responses in quantum plasmonic metasurfaces composed of metallic nano-objects with subnanometer gaps were investigated using time-dependent density functional theory, a fully quantum mechanical approach. At gap distances of ≥ 0.6 nm, the third-order nonlinearities monotonically increased as the gap distance decreased, owing to enhancement of the induced charge densities at the gaps between nano-objects. Particularly, when the third harmonic generation overlapped with the plasmon resonance, a large third-order nonlinearity was achieved. At smaller gap distances down to 0.1 nm, we observed the appearance of extremely large third-order nonlinearity without the assistance of the plasmon resonance. At a gap distance of 0.1 nm, the observed third-order nonlinearity was approximately three orders of magnitude larger than that seen at longer gap distances. The extremely large third-order nonlinearities were found to originate from electron transport by quantum tunneling and/or overbarrier currents through the subnanometer gaps.

This paper proposes Isochronous-MAC (I-MAC), which utilizes low-frequency radio waves time synchronization for sensor networks. Using IMAC, based on the Low Power Listening (LPL), all sensor nodes wake and listen channel periodically and synchronously. Since a sender can easily predict wakeup time of an intended receiver, it can shorten the length of preamble to make the receiver prepare for reception of the following data packet. This saves power consumption for the sender to rendezvous with the receiver. In the paper, we use an analytical model to investigate the impact of the data transmission frequency, the number of neighboring nodes, the wakeup period, the clock drift, and the time -synchronization frequency on the power consumption for consideration of the power overhead to perform the time synchronization. Those results demonstrate that I-MAC allows determination of any arbitrary wakeup period without much difficulty, whereas LPL requires a much more careful setting of the wakeup period because its optimum wakeup period is sensitive to the frequency of data transmission as well as to the number of neighboring nodes. Therefore, IMAC has a great potential to reduce the power consumption in most situations compared with LPL, in spite of the overhead to perform time synchronization.

Abstract-A novel hybrid simulation based on the coupled Maxwell-Schrödinger equations has been utilized to investigate, accurately, the dynamics of electron confined in a one-dimensional potential and subjected to time-dependent electromagnetic fields. A detailed comparison has been made for the computational results between the Maxwell-Schrödinger and conventional Maxwell-Newton approaches, for two distinct cases, namely, characterized by harmonic and anharmonic electrostatic confining potentials. The results obtained by the two approaches agree very well for the harmonic potential while disagree quantitatively for the anharmonic potential. This clearly indicates that the MaxwellSchrödinger scheme is indispensable to multi-physics simulation particularly when the anharmonicity effect plays an essential role.