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Inverse problems are important in quantum mechanics and involve such questions as finding which potential give a certain spectrum or which arrangement of atoms give certain properties to a molecule or solid. Inverse problems are typically very hard to solve and tend to be very compute intense. We here show that neural networks can easily solve inverse problems in quantum mechanics. It is known tha
In a quantum-mechanical system, particle-hole duality implies that instead of studying particles, we can get equivalent information by studying the missing particles, the so-called holes. Using this duality picture for fermions in a rotating trap the vortices appear as holes in the Fermi sea. Here we predict that the formation of vortices in quantum dots at high magnetic fields causes oscillations
We use a numerical model based on non-equilibrium Green's functions to investigate the influence of interface roughness (IFR) scattering in terahertz quantum cascade lasers. We confirm that IFR is an important phenomenon that affects both current and gain. The simulations indicate that IFR causes a leakage current that transfers electrons from the upper to the lower laser state. In certain cases,
Abstract is not available
Coupled cluster methods are compared to multiconfigurational second-order perturbation theory in a study of the high spin d(x)s(2) -> d(x+1)s(1) excitations in first, second, and third row transition metals. Large basis sets of the atomic natural orbital type are used. Scalar relativistic effects are included using the Douglas-Kroll-Hess Hamiltonian. The effect of spin-orbit coupling is demonstrat
Plasmonic materials have optical cross sections that exceed by 10-fold their geometric sizes, making them uniquely suitable to convert light into electrical charges. Harvesting plasmon-generated hot carriers is of interest for the broad fields of photovoltaics and photocatalysis; however, their direct utilization is limited by their ultrafast thermalization in metals. To prolong the lifetime of ho
Over the last decade it has been pointed out by several philosophers that not all Status Function Declarations are synchronic: some such declarations are directed toward the absolute past. Such Status Function Declarations are perplexing if one is an ontic realist with respect to institutional properties and states of affairs. If successful, such Status Function Declarations seem to change the absOver the last decade it has been pointed out by several philosophers that not all Status Function Declarations are synchronic: some such declarations are directed toward the absolute past. Such Status Function Declarations are perplexing if one is an ontic realist with respect to institutional properties and states of affairs. If successful, such Status Function Declarations seem to change the abs
Nobelpriset 2023 Professor Anne L’Huillier, vid avdelningen för atomfysik på fysiska institutionen, belönades med Nobelpriset i fysik 2023 tillsammans med Pierre Agostini och Ferenc Krausz för deras experiment som gett mänskligheten nya verktyg för att utforska elektronernas värld inuti atomer och molekyler.Mer om Nobelpriset och Anne L´Hullier på LTH:s webbplats. Våra forskningsavdelningar Astrof
https://www.fysik.lu.se/forskning - 2026-09-05
Coherent radiation from a relativistic electron beam is a valuable way to overcome the present limitations of conventional lasers and synchrotron radiation light sources. The typical scheme has electrons, directly from a linac, in a single-pass interaction with a laser pulse in the presence of a static undulator magnetic field. We demonstrate that a storage-ring free-electron laser can also achiev
In magnetomotive ultrasound imaging, the tissue displacement due to a magnetic force on embedded magnetic nanoparticles is measured. It was previously shown that the nanoparticle contrast agent exhibits a non-linear magnetization characteristic, which is also reflected in the magnetomotive force. However, this non-linearity was rarely taken into account for the application. Here, the implications
In this paper, we review the physics of harmonic generation in gases and production of short attosecond pulses. Different methods to ensure a sufficient degree of synchronization, for example, selecting the cutoff region of the spectrum or compressing of attosecond pulses with apertures and metallic filters are presented
High-order harmonic generation (HHG) in gases leads to short-pulse extreme ultraviolet (XUV) radiation that is useful in a number of applications, such as attosecond science and nanoscale imaging. However, this process depends on many parameters, and there is still no consensus on how to choose the target geometry to optimize the source efficiency. We review the physics of HHG with emphasis on the
Surface interactions of water with nano-TiO2 and structurally related group IV metal dioxide nanoparticles have been investigated using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The investigated clusters include 46 and 92 unit models of TiO2 (i.e., (TiO2)(46) and (TiO2)(92)) of the three low-energy polymorphs of TiO2: anatase, rutile, and brookite. The investiga
