66 research outputs found
Optimal control for feedback cooling in cavityless levitated optomechanics
No full textWe consider feedback cooling in a cavityless levitated optomechanics setup, and we investigate the possibility to improve the feedback implementation. We apply optimal control theory to derive the optimal feedback signal both for quadratic (parametric) and linear (electric) feedback. We numerically compare optimal feedback against the typical feedback implementation used for experiments. In order to do so, we implement a state estimation scheme that takes into account the modulation of the laser intensity. We show that such an implementation allows us to increase the feedback strength, leading to faster cooling rates and lower center-of-mass temperatures
Bounds on quantum collapse models from matter-wave interferometry: Calculational details
No full textWe present a simple derivation of the interference pattern in matter-wave interferometry as predicted by a class of master equations, by using the density matrix formalism. We apply the obtained formulae to the most relevant collapse models, namely the Ghirardi-Rimini-Weber (GRW) model, the continuous spontaneous localization (CSL) model together with its dissipative (dCSL) and non-markovian generalizations (cCSL), the quantum mechanics with universal position localization (QMUPL) and the Di\'{o}si-Penrose (DP) model. We discuss the separability of the collapse models dynamics along the 3 spatial directions, the validity of the paraxial approximation and the amplification mechanism. We obtain analytical expressions both in the far field and near field limits. These results agree with those already derived in the Wigner function formalism.
We compare the theoretical predictions with the experimental data from two relevant matter-wave experiments: the 2012 far-field experiment and the 2013 Kapitza Dirac Talbot Lau (KDTL) near-field experiment of Arndt's group. We show the region of the parameter space for each collapse model, which is excluded by these experiments. We show that matter-wave experiments provide model insensitive bounds, valid for a wide family of dissipative and non-markovian generalizations
Model of self-sufficient electric energy supply
No full textV današnjem času spremljamo čedalje večje število sončnih elektrarn in baterijskih hranilnikov, kar nakazuje potrošniško nagnjenost k samooskrbi. S povečanim interesom v samooskrbo se pojavi vprašanje o vplivu samooskrbe na omrežje. Cilj te diplomske naloge je razvoj modela, ki mogoča simuliranje samooskrbe in vpliva le-te na omrežje.
Razvit model samooskrbe je napisan v programskem jeziku Python s pomočjo odprtokodne knjižnice pandapower. Model ima tri večje komponente in to so porabnik, sončna elektrarna in baterija. Simulacije so opravljene na realnih merilnih podatkih moči porabnikov in generiranih podatkih proizvodnje sončne elektrarne na podlagi realnih vremenskih podatkov.
S pomočjo modela analiziramo vpliv samooskrbe na omrežje. Z obravnavanimi parametri dosežemo 23,3% zmanjšanje obremenitve na omrežje s priključitvijo sončne elektrarne na objekt in 35,26% zmanjšanje obremenitve na omrežje s priključitvijo sončne elektrarne in baterijskega hranilnika energije.
Samooskrba tako predstavlja velik potencial pri razbremenitvi omrežja in omogoča boljše delovanje omrežja na dolgi rok, vendar ne brez izzivov. Sistemski operater se bo z večjim deležem samooskrbe srečal z izzivi stabilnosti omrežja in kakovosti energije zaradi variabilnosti in nepredvidljivosti proizvodnje samooskrbe. Z izboljšavami in raziskavami na tem področju, bomo tako prispevali k bolj trajnostni in okolju prijazni energetski prihodnosti.In recent times, we are witnessing an increasing number of solar power plants and battery storage systems, indicating a consumer inclination towards self-sufficiency. With the growing interest in self-sufficiency, questions arise about its impact on the grid. The aim of this thesis is to develop a model that allows for the simulation of self-sufficiency and its effects on the grid.
The developed self-sufficiency model is written in Python using the open-source library pandapower. The model has three major components, these being, the consumer, the solar power plant, and the battery. Simulations are conducted using real measurement data of consumer power and generated data of solar power production based on real weather data.
With the help of the model, we analyze the impact of self-sufficiency on the grid. With the parameters considered, a 23.3% reduction in grid load is achieved by connecting a solar power plant to a facility, and a 35.26% reduction in grid load is achieved by connecting both a solar power plant and an energy storage battery.
Thus, self-sufficiency represents significant potential for reducing grid load and enabling better grid performance in the long term, however, not without challenges. With a higher rates of self-sufficiency, the system operator will face challenges in grid stability and energy quality due to the variability and unpredictability of self-sufficient production. Through improvements and research in this field, we will contribute to a more sustainable and environmentally friendly energy future
Massive quantum systems as interfaces of quantum mechanics and gravity
No full textThe traditional view from particle physics is that quantum-gravity effects should become detectable only at extremely high energies and small length scales. Owing to the significant technological challenges involved, there has been limited progress in identifying experimentally detectable effects that can be accessed in the foreseeable future. However, in recent decades the size and mass of quantum systems that can be controlled in the laboratory have reached unprecedented scales, enabled by advances in ground-state cooling and quantum-control techniques. Preparations of massive systems in quantum states pave the way for the explorations of a low-energy regime in which gravity can be both sourced and probed by quantum systems. Such approaches constitute an increasingly viable alternative to accelerator-based, laser-interferometric, torsion-balance, and cosmological tests of gravity. In this review an overview of proposals where massive quantum systems act as interfaces between quantum mechanics and gravity is provided. Conceptual difficulties in the theoretical description of quantum systems in the presence of gravity are discussed, tools for modeling massive quantum systems in the laboratory are reviewed, and an overview of the current state-of-the-art experimental landscape is provided. Proposals covered in this review include precision tests of gravity, tests of gravitationally induced wave-function collapse and decoherence, and gravity-mediated entanglement. The review concludes with an outlook and summary of the key questions raised
Colored and dissipative continuous spontaneous localization model and bounds from matter-wave interferometry
No full textMatter-wave interferometry is a direct test of the quantum superposition principle for massive systems, and of collapse models. Here we show that the bounds placed by matter-wave interferometry depend weakly on the details of the collapse mechanism. Specifically, we compute the bounds on the CSL model and its variants, provided by the the KDTL interferometry experiment of Arndt's group [Phys. Chem. Chem. Phys., 2013, 15, 14696-14700], which currently holds the record of largest mass in interferometry.
We also show that the CSL family of models emerges naturally by considering a minimal set of assumptions. In particular, we construct the dynamical map for the colored and dissipative Continuous Spontaneous Localization (cdCSL) model, which reduces to the CSL model and variants in the appropriate limits. In addition, we discuss the measure of macroscopicity based on the cdCSL model
Bohmian mechanics, collapse models and the emergence of classicality
No full textWe discuss the emergence of classical trajectories in Bohmian mechanics, when a macroscopic object interacts with an external environment. We show that in such a case the conditional wave function of the system follows a dynamics which, under reasonable assumptions, corresponds to that of the Ghirardi–Rimini–Weber (GRW) collapse model. As a consequence, Bohmian trajectories evolve classically. Our analysis also shows how the GRW (istantaneous) collapse process can be derived by an underlying continuous interaction of a quantum system with an external agent, thus throwing a light on how collapses can emerge from a deeper level theory
Slovene-Friulian-Italian Literary Connections at the Beginning of the 20th Century: The Case of Alojz Gradnik and Select Friulian and Italian author
No full textBased on the case of Alojz Gradnik (1882–1967), this article deals with previously unresearched Slovene-Friulian-Italian literary connections that occurred during the last years of the Austro-Hungarian Empire and the first years after WWI along the border of today’s Slovenia (Goriška Brda) and Italy (the region of Friuli-Venezia Giulia: the Provinces of Gorizia, Udine and Trieste). The article highlights the parallels in motifs, themes, ideas and form, as well as the connections between Alojz Gradnik and select Friulian and Italian authors from this region. These links are the consequence of living in a joint cultural space and Gradnik’s Friulian family ties, especially with his cousin Maria Samer. The research uncovers certain differences in motifs, themes and ideas stemming from different national identities. Gradnik’s poetry is closest to Friulian lyrical poetry in their descriptions and experiences of a rural setting, predominantly the deep bond felt between the farming people and native land coupled with their terrible social strife. Gradnik and his contemporary Friulian authors also coincide in works with a nationalist theme – on the threshold of WWI both Slovene and Friulian authors infused their work with their personal vision for the future of their own community. They shared a negative literary depiction of the Austro-Hungarian Empire, and the wish to secure a better economic future, to protect and solidify their cultural heritage. Gradnik’s poetry and that of the contemporary Italian (irredentist) authors share a similar literary technique that depicted the national identities of today’s border between Italy and Sloveniathey were ideologically opposed however: while the Italians depicted the Italian view of the region, Gradnik highlights the presence of a Slavic element within the regio
General Galilei Covariant Gaussian Maps
No full textWe characterize general non-Markovian Gaussian maps which are covariant under Galilean transformations. In particular, we characterize translational and Galilean covariant maps and show that they reduce to the known Holevo result in the Markovian limit. We apply the results to discuss measures of macroscopicity based on classicalization maps, specifically addressing dissipation, Galilean covariance and non-Markovianity. We further suggest a possible generalization of the macroscopicity measure defined in Nimmrichter and Hornbergerl. [Phys. Rev. Lett. 110, 16 (2013)]
Marisa Madieri, Jan Morris e Irena Žerjal
No full textThis paper analyses the ways in which the town of Trieste and its surrounding area are portrayed in literary
works in the period following World War II. To this end, we have adopted a comparative approach in analysing
three novels about the town of Trieste written by Irena Žerjal, Marisa Madieri and Jan Morris, belonging to different
cultural and language traditions. Our analysis applied an interdisciplinary approachgeocriticism and literary imagology as well as the concepts of traumatic collective memory and postmemory. From a geocritical perspective,
we have interpreted the literarisation of the town of Trieste from three different perspectives: the perspective of a
Slovene author (Irena Žerjal)the Western-European perspective (Jan Morris)and the exile’s perspective (Marisa
Madieri). All three authors adopt a similar approach in their literary representations of the town of Trieste, namely
going back in time, which allows them to shift the action from the present to the past, i.e. to Trieste as they knew it
in their youth. In doing so, each author focuses on a different part of town. In those rare occurrences where action
is set in the same places, each author ascribes a different meaning to the location. While the authors acknowledge
the presence of the Other in Trieste, this has a negligible impact on the novel’s course of action
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