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Recent Submissions

Fast Qubit Control with a Quantum-Circuit Refrigerator
(Aalto University, 2024) Mörstedt, Timm Fabian; Kundu, Suman, Dr., Department of Applied Physics, Aalto University; Teknillisen fysiikan laitos; Department of Applied Physics; QCD Labs; Perustieteiden korkeakoulu; School of Science; Möttönen, Mikko, Prof., Department of Applied Physics, Aalto University
Superconducting circuits have emerged as powerful building blocks on the path toward a useful quantum computer. However, fast and accurate control over these circuits remains one of the key challenges. In particular, the fast initialization of superconducting qubits is a growing requirement in this era of constantly increasing qubit lifetimes. In this thesis, we investigate different means of qubit control in the context of dissipation engineering. We use a quantum-circuit refrigerator (QCR), an on-chip microcooler based on one or two normal-metal–insulator–superconductor junctions, to create a tunable environment for superconducting circuits. We present and compare two different realizations of this device, the double-junction QCR directly coupled to a transmon qubit and the single-junction QCR coupled to the qubit via a superconducting resonator. Beyond qubit reset, we explore other properties of the QCR, including the cooling and creation of exceptional points in superconducting resonators and the generation of thermal states in superconducting qubits. Through single-shot readout experiments, we gain insight into the quantum state of the qubit and its dynamics in response to different control signals. Combining the results of these experiments, we discuss the possible realization of a quantum heat engine using a QCR as a two-way tunable environment, extending the scope of applications toward the fundamental study of open quantum systems. This thesis sheds light on the versatile world of quantum-circuit refrigeration and presents novel insights, experiments, and applications. At the intersection of circuit quantum electrodynamics and quantum thermodynamics, the QCR promises further possibilities for advancement and increased understanding of the behavior and control of superconducting quantum systems.
Investigation of decarbonisation options for load and haul equipment in quarry mining
(2024-05-20) Kegels, Thibaud Ludo Liliane; Shishevan Soleymani, Masoud; Scrutton, Mark; Insinööritieteiden korkeakoulu; Rinne, Mikael
The importance of decarbonization in various industries is growing significantly, especially when it comes to LHD equipment in the minerals and metals industry. Conventional diesel load and haul (LHD) equipment used in quarrying and mining operations have drawbacks that result in the emissions of hydrocarbon and greenhouse gases that need to be reduced to reach the Net Zero Emissions scenario. Decarbonization options that could replace diesel equipment include battery electric vehicles, green hydrogen, and alternative fuels. This project aims to give an overview of current and near future available decarbonization methods and to analyse the environmental benefit, cost effectiveness and technological feasibility of these alternatives to diesel fuel. The case study used to simulate and compare the three different decarbonization options is a mountaintop marble quarry based in Ipoh, Malaysia. A comparison has been made with Ipoh located in Malaysia and a hypothetical situation of Ipoh located in France to show the true potential of decarbonization as Malaysia does not incentivize businesses to reduce emissions due to their subsidies on the use of fossil fuel. Malaysia’s energy mix consist of primarily unabated fossil fuels. The proposed workflow involves an extensive literature review of current and near-future decarbonisation technologies to replace diesel equipment and to create a haulage network based on block model data using the software Xpac Quarry solutions and its Haulnet package. Diesel equipment is imported from the Quarry solutions database and used as a base case to compare BEV and trolley assist simulations. Hydrogen and HVO fuel consumption have been calculated manually to obtain NPVs and associated emissions. An investigation into required infrastructure and energy requirements has been done to accurately define costs and resulting total CO2eq emissions. The results indicate that replacing diesel at Ipoh with any of the decarbonization methods will result in a negative NPV as the infrastructure requirements need extensive capital investment of which the payback period often exceeds the life of mine. The least expensive method to implement HVO fuels, followed by BEVs and green hydrogen. Furthermore, it has been found that using BEVs instead of diesel at Ipoh is more environmentally polluting because producing 1 kWh of electricity is more polluting than producing the same energy worth of diesel. Green hydrogen is the least polluting method with no greenhouse gas emissions associated with it, followed by alternative fuels. When investigating the technological feasibility of the three main decarbonization options, hydrogen is the furthest away of being technologically feasible as from now. No green hydrogen using water electrolysers has been produced at an industrial scale, and a lack of technical expertise and infrastructure is present regarding distribution, transportation, and storage. Currently, no hydrogen LHD equipment is commercially available currently, and the same applies to BEVs that could replace the current equipment used at Ipoh. To bridge this gap, alternative fuels are the best option, but the market is competitive, and supply is limited. This project has given a good overview of current possibilities and clearly shows today’s options for decarbonisation and where industries stand with respect to infrastructure and equipment.
Regulatory Reporting and Competitive Advantage for Banks
(2024-06-19) Sundström, Anders; Karhu, Kimmo; Perustieteiden korkeakoulu; Karhu, Kimmo
In the European Union banks are heavily regulated and obliged to provide extensive information about their activities to their supervisory organizations. This thesis examines whether regulatory reporting and its implementation affects banks’ competitive advantage. The research question is whether the regulatory reporting that banks do affects their competitive advantage. This question is examined through a series of interviews with employees from various teams in a medium-sized Finnish bank. The interviews are semi-structured and the results of the interviews are interpreted to yield key concepts related to the research question. The results suggest that banks might be able to use reporting data as a means to become a data-driven organization. In addition to this, banks can use the regulatory definitions in their own business and use new regulation and report data as an impetus for learning new topics that they had not engaged with before.
Content Recommendation with Knowledge Graphs in Information Management Systems
(2024-06-17) Huovila, Maria; Singh, Ramanpreet; Perustieteiden korkeakoulu; Holme, Petter
Organizations around the world are battling with vast amounts of information. With increasing amount of data, effectively finding the needed information from information management system (IMS) becomes rapidly more difficult. Users have high expectations for efficiency and experience frustration when the information isn’t readily available. Content recommendation (CR) systems have high potential in increasing efficiency and user experience. CR systems can be divided into collaborative filtering, content-based and hybrid recommendation systems. By the means of literature study characteristic of different approaches were evaluated. In IMS where even less popular information can be valuable and there are is much content compared to the number of users, content-based approach is promising. Knowledge Graphs (KG) have high potential in enhancing the quality of recommendations when structured information about the content is available. Based on network analysis conducted for the content of an IMS, it appears that integrating KG with the recommendation system could potentially be beneficial. Further analysis about the structure and performance tests of the recommendation system are needed to establish its true value.
Practical implementation of simultaneous, synchronous MEG and thalamic LFP recordings using a novel deep brain stimulation device
(2024-06-17) Järvinen, Elli; Pauls, Amande; Perustieteiden korkeakoulu; Renvall, Hanna
Epilepsy is one of the most common neurological diseases worldwide, and it is characterised by a permanent predisposition to spontaneous epileptic seizures. One third of epilepsy patients do not respond adequately to antiepileptic drugs. One potential treatment option for drug resistant epilepsy is deep brain stimulation (DBS). A novel DBS device, the Percept PC, can deliver electrical stimulation and record local field potentials (LFPs) simultaneously, and is magnetoencephalography (MEG) compatible. This allows for detailed research to identify biomarkers of treatment effects, with a long-term goal to develop closed-loop DBS protocols in epilepsy. The goal of this study was (1) to implement simultaneous MEG and LFP recordings in practise, (2) to explore how the Percept PC device records LFP data, and (3) to investigate options for synchronizing the MEG and LFP signals. The study consisted of in vitro test measurements and one patient measurement. An experimental pipeline was successfully implemented for collecting simultaneous MEG and LFP data and to guide the use of Percept PC device during the recordings. Rhythmic tapping on the implantable pulse generator appeared as the most promising synchronization method, although potential problems with repeatability should be considered, and synchronization based on cardiac signal artifact needs further investigation.