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Second harmonic generation is analyzed from a microscopical point of view using a non-equilibrium Green's function formalism. Through this approach the complete on-state of the laser can be modeled and results are compared to experiment with good agreement. In addition, higher order current response is extracted from the calculations and together with waveguide properties, these currents provide t
We study the exciton dynamics in an optically excited nanocrystal quantum dot. Multiple exciton formation is more efficient in nanocrystal quantum dots compared to bulk semiconductors due to enhanced Coulomb interactions and the absence of conservation of momentum. The formation of multiple excitons is dependent on different excitation parameters and the dissipation. We study this process within a
By measuring a linear response function directly, such as the dynamic susceptibility, one can understand fundamental material properties. However, a fresh perspective can be offered by studying fluctuations. This can be related back to the dynamic susceptibility through the fluctuation–dissipation theorem, which relates the fluctuations in a system to its response, an alternate route to access the
In this report we study systems governed by the Saint-Venant shallow water equations interacting with boundary conditions including control. We derive closed form formulas for the open-loop behavior. These formulas rely on first, second and third order approximations which are based on a perturbation that we develop. Properties of these solutions are studied and comparisons with existing non-linea
6 maj 2026 12:15 till 12:45 | Föreläsning A documentary history of the use of so-called confidential human sources by a national security service, Michael Schoenhals book "Eyes and Ears: Secret Agent Work in Cold War China" foregrunds the supremacy of access to evidence as the foundation of the historical discipline by exploring, translating, and analysing primary sources from 1947 to 1973. The bo
https://www.lu.se/evenemang/citizen-spies-our-midst - 2026-07-14
