Mars’ climate has undergone many massive changes over the course of it’s lifetime. In order toestablish how Mars lost the vast majority of its water, we must be able to understand how Marsis losing its atmosphere today. By understanding the current escape rates of H and D and theprocesses that control them, we can extrapolate back in time to model the escape rates under pastconditions. By using the Exospheric General Model (EGM) developed by researchers at LATMOS,Sorbonne University, I have simulated the density profiles and escape rates of H, D, related isotopesand particles due to collisions with hot oxygen particles in the Martian exosphere at the currentepoch at mean solar activity. By adding H and D to the model and implementing changes to theprogram between simulations, I have improved the accuracy of the escape rate of these particlesfrom Mars in the EGM. While my results for H, H2 and HD reflect what has been observed fromin-situ Martian Satellite, MAVEN, future work is needed to include the solar wind interaction for Din the model, as it has been shown to be significant and has been left out of this work.

A study was made in order to deduce whether certain chemical species, namely water (H2O) and carbon monoxide (CO), are present in the atmosphere of the exoplanet WASP-107 b, which lies about 200 light-years away from Earth in the constellation Virgo. The project was carried out at Uppsala University at the Department of Physics and Astronomy. This was done through the use of transmission spectroscopy and executed using a cross-correlation technique, one of the leading methods available today to extract exoplanetary atmospheric information. The data used was collected during a transit which occured in March 2022, originally gathered by the spectrograph CRIRES+ stationed at Very Large Telescope (VLT) in Paranal. WASP-107 b is a warm Jupiter-type planet, and since the aforementioned chemical species exhibit spectral lines mainly in the infrared (0.95-5.3 μm), it makes CRIRES+ a desirable instrument due to its specialization for working in the infrared. The data analysis was performed using several scripts built in Python with subsequent data-reduction methods. The data-reduction methods used for this purpose was the standard ESO CRIRES+ data reduction pipeline which includes removal of systemic sources of noise such as dead pixels and cosmic rays, and SysRem, which is an algorithm used to remove any trends with time and any constant features in time for each pixel time series. SysRem is currently one of the most efficient way available for doing so, and is commonly used in these types of studies. Several detection maps were then generated and studied in order to deduce whether a detection had been made or not. For this project, one exoplanet was examined and its atmosphere was probed for H2O and CO. The cross-correlation templates utilized were a combination of both species as well as one corresponding to only CO. The detection maps generated from the cross-correlation analysis initially suggested non-detections for all combinations of SysRem iterations and templates, except for two which presented features that might imply a detection but without any strong certainty. Those results indicate the possible existence of CO in the atmosphere of WASP-107 b, but further investigation is needed in order to determine their validity. / Denna rapport beskriver en studie som utförts för att undersöka ifall vissa kemiska arter, nämligen vatten (H2O) och kolmonoxid (CO), existerar i atmosfären kring exoplaneten WASP-107 b. Exoplaneten ligger cirka 200 ljusår bort från jorden i konstellationen Jungfrun. Arbetet utfördes på Uppsala universitet på institutionen för fysik och astronomi, eller Department of Physics and Astronomy. Detta gjordes huvudsakligen med hjälp av transmissionsspektroskopi och cross-correlation - en av de ledande metoderna idag för att analysera exoplanetära atmosfärer. Datan som använts för denna studie samlades in under en transit som skedde i mars 2022 med hjälp av spektrografen CRIRES+, stationerad vid Very Large Telescope (VLT) i Paranal. WASP-107 b klassas som en varm Jupiter, och eftersom de undersökta kemiska arterna huvudsakligen uppvisar spektrallinjer i det infraröda området (0.95-5.3 μm), är CRIRES+ ett sunt val då spektrografen är specialiserad på att undersöka infrarött ljus. Dataanalysen utfördes genom användningen av flertal script, byggda i Python med påföljande datareduktion. De datareduktionsmetoder som användes i detta syfte var ESO CRIRES+ standard data reduction pipeline, vilken inkluderar avlägsnandet av systematiska källor till brus såsom döda pixlar och den kosmiska bakgrundsstrålningen, och SysRem, vilket är en algoritm som används för att ta bort trender samt konstanta drag beroende på tid utmed varje pixelserie. I nuläget är SysRem en av de mer effektiva sätten att göra detta på, och är en vanlig metod i studier som denna. I detta projekt blev en exoplanet undersökt och dess atmosfär granskad för att se ifall H2O och CO förekommer i den. De cross-correlation templates som användes bestod av en som använde en kombination av båda kemiska arter, tillika en som endast detekterade CO. De detection maps som genererats från cross-correlation analysen föreslog först en ickedetektion för alla kombinationer av SysRem iterationer och templates, förutom två, vilka uppvisade signalement som möjligtvis indikerade en detektion, men utan särskild stark säkerhet. Dessa resultat föreslog en möjlig detektion av CO i atmosfären, men för att säkerställa detta krävs vidare undersökning.

Since more and more customers switch to online purchases, the last-mile delivery problemhas created a huge burden on companies and cities. The increasing parcel delivery leads toextra operational costs in logistics and congestion in cities. IKEA, the furniture retailcompany, is going to propose a project – IKEA Urban Multi Hub to solve this problem byallowing customers to carry back orders themselves. This study collaborates with IKEA toinvestigate and formulate a robust hub that customers are willing to visit. The aim of thisresearch is to identify appropriate locations for the hub and possible future mobility that thehub should provide. Moreover, develop concepts and strategies for two cities - Shanghai cityand New York City.Research and customer interview were fundamental parts of this project. The research partincludes literature review and background that helps to preliminary clarify urban conditions,possible future mobility, and travel behavior. The customer interview part investigatescustomers’ preferences in two selected cities which helps to realize their needs and gaininspiration. The results showed that clustering with metro stations and providingautonomous mobility may create a smooth customer self-delivery experience for IKEA UrbanMulti Hub. Besides, cooperating with logistic companies can reduce the operation risk of theHub and strengthen the business model. Further concepts and strategies developed for twoselected cities are described in the thesis.

Cosmology is the study of the universe as a whole, and attempts to describe the behaviour of the universe mathematically. The simplest relativistic cosmological models are derived from Einstein's field equations with the assumptions of isotropy and homogeneity. In this thesis, a few simple cosmological models will be derived and evaluated with respect to their description of our universe i.e., how well they match observational data from e.g., the cosmic background radiation and redshift from distant supernovae. The models are derived from Einstein's field equations, which is why a large portion of the thesis will lay the ground work for the field equations by introducing and explaining the language of tensors. / Kosmologi är läran om universum i stort samt dess matematiska beskrivning. De enklaste relativistiska kosmologiska modellerna kan härledas från Einsteins fältekvationer med hjälp av antaganden om isotropi och homogenitet. I denna rapport kommer ett par av de enklaste modellerna att härledas, samt evalueras baserat på hur väl de beskriver vårt universum, det vill säga hur bra de passar de observationer som gjorts på exempelvis den kosmiska bakgrundsstrålningen och rödskifte från avlägsna supernovor. Modellerna härleds utifrån Einsteins fältekvationer, varför en stor del av rapporten består av en introduktion till tensoranalys.

Lyman continuum (LyC) photons are known to be responsible for reionising the universe after the end of the Dark Ages, which marked a period called the Epoch of Reionisation (EoR). While these high-energy photons are thought to predominantly originate from young, hot, massive stars within the earliest galaxies, and contributions from high-energy sources like quasars and AGN, the origins of these photons are yet not well known and highly debated. Detecting LyC photons from the early galaxies near the EoR is not possible as they get completely absorbed by the intergalactic medium (IGM) on their way to us, which has prompted the development of various indirect diagnostics to study the amount of LyC photons contributed by such galaxies by studying their analogues at low redshifts. In this study, we probe the ionised interstellar medium (ISM) of seven Green Pea galaxies through spatially resolved[O III] λ5007/[O II] λ3727 (O32) and [O III] λ5007/Hα λ6562 (O3Hα) emission-line ratio maps, using data from the Multi Unit Spectroscopic Explorer (MUSE) onboard the Very large telescope (VLT). Out of the two ratios, the former has proven to be a successful diagnostic in predicting Lyman continuum emitters (LCEs). Along with the line ratio maps, the surface brightness profiles of the galaxies are also studied to examine the spatial distribution of the emission lines and the regions from which they originate. The resulting maps indicate whether the ISM of the galaxies is ionization-bounded or density-bounded. Our analysis reveals that a subset of the galaxies with ionization-bounded ISM exhibits pronounced ionisation channels in the outer regions. These channels are potential pathways through which Lyman continuum photons may escape. For density-bounded ISM, the ionised ISM extends well beyond the stellar regions into the halos of the galaxies, highlighting their potential contribution to the ionising photon budget during the EoR. The findings emphasise the importance of spatially resolved ISM studies in understanding the mechanisms facilitating the escape of LyC photons.

Hawking radiation is a phenomenon where the combination of geometry of spacetime around a black hole and quantum effects near its event horizon causes particle emission. Stephen Hawking was one of the first to make computations and conclude that this is valid for every black hole in general. Therefore, the goal of the project was to understand how the presence of a black hole changes geometry of spacetime, explore some of its peculiar properties and, finally, connect it to Hawking radiation. It turns out that one way to describe geometry around a black hole is to use the Schwarzchild metric which fully describes surroundings of a non-rotating and uncharged black hole. Using the so called Klein-Gordon equation and some additional computations one then sees that there’s indeed a particle emission. However, the radiation appears to be observer dependent which is due to curvature near event horizon. Hawking radiation has temperature which happens to be extremely small to detect, but this result reveals the fact that black holes radiate faster as they shrink. However, the time it takes for an arbitrary black hole to evaporate is much longer than the age of the Universe. Encountering those and some other challenges Hawking radiation remains hypothetical. / Hawkingstrålning är ett fenomen där kombinationen av geometri av rumtid runt ett svart hål och kvantmekaniska effekter nära dess händelsehorisont leder till partikel emission. Stephen Hawking var bland de första att göra beräkningar och dra slutsatsen att detta är giltigt för alla svarta hål. Syftet med projektet var därför att förstå hur närvaron av ett svart hål ändrar geometri av rumtid, undersöka dess vissa speciella egenskaper samt anknyta det till Hawkingstrålning. Det visar sig att ett sätt att beskriva geometri kring ett svart hål är att använda Schwarzchild metriken som helt beskriver omgivningen av ett icke roterande och oladdat svart hål .Använder man sig av så kallade Klein-Gordon ekvationen och några ytterligare beräkningar så kommer man till slutsaten att det verkligen finns enemission av partiklar. Emissionen verkar dock vara observatörsberoende på grund av krökning nära händelsehorisont. Hawkingstrålning har temperatur som visar sig vara extremt liten för att upptäcka, men resultaten avslöjar faktumet att svarta hål strålar ut snabbare då de krymper. Tiden det tar för ett godtyckligt svart hål att koka bort är dock mycket längre än åldern of Universum. På grund av dessa och några andra utmanningar återstår Hawkingstrålning hypotetiskt.

The problem of how quantum mechanics gives rise to classicality has been debated for more than a century. A commonly proposed solution is decoherence, i.e. the gradual decay of superpositions in open quantum systems due to their inevitable interaction with their environment. However, the ability of decoherence to account for all aspects of the classical world is often questioned. A recently proposed model suggests that decoherence can occur even in isolated composite systems subject to gravitational time dilation, something which has sparked a debate. In this thesis we attempt to identify the precise role of decoherence in the quantum-to-classical transition (QTCT) and then use the result to analyze the validity of the newly proposed time dilation-induced decoherence mechanism. We find that the problem of the QTCT can be divided into two parts and that decoherence solves the first of these whereas the second is unsolvable without fundamental modifications to quantum theory. Moreover, we argue that the effect is fundamentally frame-dependent and we find a general formula for the rate of decoherence of macroscopic superpositions in the case where both the system and observer use Rindler coordinates. The result suggests that the frame-dependence may be utilized to increase the strength of the effect in experimental settings. Finally, the possibilities of experimental verification are discussed and we argue that recent advances in quantum measurement techniques in gravitational-wave observatories may enable tests of gravitational decoherence in the near future, finally providing an empirical glimpse into the resolution of one of the most critical debates in all of physics. / Huruvida kvantfysiken kan ge uppkomst till den klassiska fysiken på stora skalor är ett problem som diskuterats under mer än ett århundrade. En föreslagen lösning är dekoherens, alltså det gradvisa sönderfallet av superpositioner i öppna kvantsystem på grund av den oundvikliga interaktionen med deras omgivning. Dekoherensens förmåga att förklara alla delar av den klassiska världen ifrågasätts emellertid fortfarande. De senaste åren har en ny effekt uppmärksammats som tyder på att dekoherens även kan uppstå i isolerade kompositsystem under påverkan av gravitationell tidsdilatation, något som orsakat en debatt i litteraturen. I detta arbete försöker vi identifiera dekoherensens roll i övergången från det kvantmekaniska till det klassiska, och vi använder sedan resultatet för att analysera den ovannämnda gravitationella dekoherensmekanismen. Det allmänna problemet med övergången från kvantfysik till klassisk fysik delas upp i två delar, och vi visar att dekoherens löser den första delen; den andra delen visar sig vara olösbar utan fundamentala förändringar av kvantfysikens ramverk. Vidare visas den gravitationella dekoherenseffekten vara observatörsberoende och vi härleder en allmän formel för takten med vilken makroskopiska superpositioner sönderfaller i de fall då både systemet och observatören använder Rindlerkoordinater. Resultaten tyder på att observatörsberoendet eventuellt kan utnyttjas för att öka effektens styrka i experimentalla sammanhang. Slutligen diskuteras möjligheter att experimentellt verifiera effekten; vi argumenterar för att nya genombrott inom kvantmätteknik i gravitationsvågsobservatorium kan möjliggöra tester av gravitationell dekoherens inom en snar framtid, vilket skulle ge oss en första empirisk inblick i lösningen till en av fysikens mest kritiska debatter.