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Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very hig
FOR EMPLOYEES AT THE DEPARTMENT OF INFORMATICS Travel bookings are made via the Cytric self-booking website. You can find out more about travel bookings on LUSEM Staff Pages. For information about travel grants, please view the page Funding and grants.Business travelFunding and grantsUsing CytricFor help with bookings and entitlements in Lucat, contact Carla Böhme.Log in to the Cytric websiteBooki
We study the radial migration of stars as a function of orbital action as well as the structural properties of a large suite of N-body simulations of isolated disc galaxies. Our goal is to establish a relationship between the radial migration efficiency of stars and their vertical action. We aim to describe how that relationship depends on the relative gravitational dominance between the disc and
Partikelkolliderare är stora maskiner som accelererar partiklar till höga energier, för att sedan låta dem kollidera. Därvid bildas ett stort antal produkter, som kan spåras i detektorer. De processer som inträffar under och efter kollisionerna beskrivs huvudsakligen av standardmodellen, en teori som klassificerar de fundamentala partiklarna och växelverkningarna mellan dessa. Även om standardmode
In this thesis, we consider a 2-Higgs-doublet model with a gauged Froggatt-Nielsen mechanism as an extension of the standard model. We assume that (i) the theory at the electroweak scale is the low energy limit of a theory defined at a scale $\Lambda_{FN}$ (ii) the Yukawa couplings at $\Lambda_{FN}$ are generated by the Froggatt-Nielsen mechanism. The first assumption is enforced by requiring that
In this thesis we investigate the properties of a specific two Higgs Doublet Model (2HDM) that can be used to explain the data on B->Dtu and B->D*tu, which deviate from the Standard Model (SM) by 3.4 sigma. The 2HDM is the simplest extension of the Standard model scalar sector. Phenomenologically it is very rich with 4 new Higgs bosons: 2 neutral and an electromagnetic charged pair. The 2HDMs exhi
This thesis gives an introduction to the basic formalism of one-dimensional supersymmetric quantum mechanics. The factorization of a Hamiltonian is used to create a supersymmetric partner Hamiltonian. The connections between the energy spectra and wave functions of these partner Hamiltonians are deduced and examined for the case of broken and unbroken supersymmetry. An extension to hierarchies of
Att bestämma omloppsbanan för en komet kan svara på många frågor omvårt solsystem, och även resten av universum. Idag använder vi oss av olika algoritmer för att preliminärt kunna beräkna omloppsbanor hos bland annat kometer, men vad krävs egentligen för att få ett någorlunda korrekt resultat? Det finns ett antal olika metoder för att bestämma omloppsbanan hos en komet, men alla är grundade i den
The multicanonical, or flat-histogram, method is a common technique to improve the sampling efficiency of molecular simulations. The idea is that free-energy barriers in a simulation can be removed by simulating from a distribution where all values of a reaction coordinate are equally likely, and subsequently reweight the obtained statistics to recover the Boltzmann distribution at the temperature
A feedback neural network approach to communication routing problems is developed, with emphasis on Multiple Shortest Path problems, with several requests for transmissions between distinct start- and endnodes. The basic ingredients are a set of Potts neurons for each request,with interactions designed to minimize path lengths and to prevent overloading of network arcs. The topological nature of
The unfolding behavior of ubiquitin under the influence of a stretching force recently was investigated experimentally by single-molecule constant-force methods. Many observed unfolding traces had a simple two-state character, whereas others showed clear evidence of intermediate states. Here, we use Monte Carlo simulations to investigate the force-induced unfolding of ubiquitin at the atomic level
This thesis will investigate the possibility to have SU(2) gauge fields as the source to the Cosmic Inflation and/or to the Dark Energy. It will be explained that, under certain conditions, the Universe can be filled with vector fields without violating its isotropy. Those conditions are naturally fulfilled within the SU(2) gauge theory. Both Einstein's equations and the equations of motion
