[{"date_created":"2021-09-30T07:53:49Z","citation":{"ama":"Jirovec D. Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole gases. 2021. doi:<a href=\"https://doi.org/10.15479/at:ista:10058\">10.15479/at:ista:10058</a>","ista":"Jirovec D. 2021. Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole gases. Institute of Science and Technology Austria.","ieee":"D. Jirovec, “Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole gases,” Institute of Science and Technology Austria, 2021.","chicago":"Jirovec, Daniel. “Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional Ge Hole Gases.” Institute of Science and Technology Austria, 2021. <a href=\"https://doi.org/10.15479/at:ista:10058\">https://doi.org/10.15479/at:ista:10058</a>.","short":"D. Jirovec, Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional Ge Hole Gases, Institute of Science and Technology Austria, 2021.","mla":"Jirovec, Daniel. <i>Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional Ge Hole Gases</i>. Institute of Science and Technology Austria, 2021, doi:<a href=\"https://doi.org/10.15479/at:ista:10058\">10.15479/at:ista:10058</a>.","apa":"Jirovec, D. (2021). <i>Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole gases</i>. Institute of Science and Technology Austria. <a href=\"https://doi.org/10.15479/at:ista:10058\">https://doi.org/10.15479/at:ista:10058</a>"},"has_accepted_license":"1","ddc":["621","539"],"date_published":"2021-10-05T00:00:00Z","year":"2021","supervisor":[{"last_name":"Katsaros","orcid":"0000-0001-8342-202X","id":"38DB5788-F248-11E8-B48F-1D18A9856A87","first_name":"Georgios","full_name":"Katsaros, Georgios"}],"language":[{"iso":"eng"}],"article_processing_charge":"No","day":"05","keyword":["qubits","quantum computing","holes"],"license":"https://creativecommons.org/licenses/by/4.0/","month":"10","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","author":[{"full_name":"Jirovec, Daniel","first_name":"Daniel","id":"4C473F58-F248-11E8-B48F-1D18A9856A87","last_name":"Jirovec","orcid":"0000-0002-7197-4801"}],"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","short":"CC BY (4.0)","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png"},"file":[{"date_created":"2021-09-30T14:29:14Z","file_name":"PHD_Thesis_Jirovec_Source.zip","date_updated":"2022-12-20T23:30:07Z","content_type":"application/x-zip-compressed","access_level":"closed","file_size":32397600,"relation":"source_file","checksum":"ad6bcb24083ed7c02baaf1885c9ea3d5","embargo_to":"open_access","creator":"djirovec","file_id":"10061"},{"relation":"main_file","file_id":"10087","embargo":"2022-10-06","creator":"djirovec","checksum":"5fbe08d4f66d1153e04c47971538fae8","access_level":"open_access","content_type":"application/pdf","date_updated":"2022-12-20T23:30:07Z","file_name":"PHD_Thesis_pdfa2b_1.pdf","date_created":"2021-10-05T07:56:49Z","file_size":26910829}],"department":[{"_id":"GradSch"},{"_id":"GeKa"}],"project":[{"call_identifier":"FWF","name":"Hole spin orbit qubits in Ge quantum wells","grant_number":"P30207","_id":"2641CE5E-B435-11E9-9278-68D0E5697425"}],"oa":1,"oa_version":"Published Version","file_date_updated":"2022-12-20T23:30:07Z","publication_identifier":{"issn":["2663-337X"]},"acknowledgement":"The author gratefully acknowledges support by the Austrian Science Fund (FWF), grants No P30207, and the Nomis foundation.","alternative_title":["ISTA Thesis"],"type":"dissertation","acknowledged_ssus":[{"_id":"M-Shop"},{"_id":"NanoFab"}],"date_updated":"2025-07-10T11:53:01Z","publication_status":"published","corr_author":"1","doi":"10.15479/at:ista:10058","abstract":[{"lang":"eng","text":"Quantum information and computation has become a vast field paved with opportunities for researchers and investors. As large multinational companies and international funds are heavily investing in quantum technologies it is still a question which platform is best suited for the task of realizing a scalable quantum processor. In this work we investigate hole spins in Ge quantum wells. These hold great promise as they possess several favorable properties: a small effective mass, a strong spin-orbit coupling, long relaxation time and an inherent immunity to hyperfine noise. All these characteristics helped Ge hole spin qubits to evolve from a single qubit to a fully entangled four qubit processor in only 3 years. Here, we investigated a qubit approach leveraging the large out-of-plane g-factors of heavy hole states in Ge quantum dots. We found this qubit to be reproducibly operable at extremely low magnetic field and at large speeds while maintaining coherence. This was possible because large differences of g-factors in adjacent dots can be achieved in the out-of-plane direction. In the in-plane direction the small g-factors, on the other hand, can be altered very effectively by the confinement potentials. Here, we found that this can even lead to a sign change of the g-factors. The resulting g-factor difference alters the dynamics of the system drastically and produces effects typically attributed to a spin-orbit induced spin-flip term.  The investigations carried out in this thesis give further insights into the possibilities of holes in Ge and reveal new physical properties that need to be considered when designing future spin qubit experiments."}],"status":"public","related_material":{"record":[{"status":"public","relation":"part_of_dissertation","id":"10066"},{"id":"10065","relation":"part_of_dissertation","status":"public"},{"id":"8831","relation":"part_of_dissertation","status":"public"},{"relation":"part_of_dissertation","id":"8909","status":"public"},{"id":"5816","relation":"part_of_dissertation","status":"public"}]},"title":"Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole gases","publisher":"Institute of Science and Technology Austria","_id":"10058","page":"151","degree_awarded":"PhD"},{"main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1909.11672"}],"publisher":"Oxford University Press","page":"3341-3362","_id":"11539","title":"The X-ray and radio activity of typical and luminous Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population","scopus_import":"1","status":"public","abstract":[{"lang":"eng","text":"Despite recent progress in understanding Ly α emitters (LAEs), relatively little is known regarding their typical black hole activity across cosmic time. Here, we study the X-ray and radio properties of ∼4000 LAEs at 2.2 < z < 6 from the SC4K survey in the COSMOS field. We detect 254 (⁠6.8per cent±0.4per cent⁠) LAEs individually in the X-rays (S/N > 3) with an average luminosity of 1044.31±0.01ergs−1 and average black hole accretion rate (BHAR) of 0.72±0.01 M⊙ yr−1, consistent with moderate to high accreting active galactic neuclei (AGNs). We detect 120 sources in deep radio data (radio AGN fraction of 3.2per cent±0.3per cent⁠). The global AGN fraction (⁠8.6per cent±0.4per cent⁠) rises with Ly α luminosity and declines with increasing redshift. For X-ray-detected LAEs, Ly α luminosities correlate with the BHARs, suggesting that Ly α luminosity becomes a BHAR indicator. Most LAEs (⁠93.1per cent±0.6per cent⁠) at 2 < z < 6 have no detectable X-ray emission (BHARs < 0.017 M⊙ yr−1). The median star formation rate (SFR) of star-forming LAEs from Ly α and radio luminosities is 7.6+6.6−2.8 M⊙ yr−1. The black hole to galaxy growth ratio (BHAR/SFR) for LAEs is <0.0022, consistent with typical star-forming galaxies and the local BHAR/SFR relation. We conclude that LAEs at 2 < z < 6 include two different populations: an AGN population, where Ly α luminosity traces BHAR, and another with low SFRs which remain undetected in even the deepest X-ray stacks but is detected in the radio stacks."}],"extern":"1","doi":"10.1093/mnras/staa476","publication_status":"published","volume":493,"date_updated":"2022-08-18T11:25:31Z","acknowledgement":"JM acknowledges the support of a Huygens PhD fellowship from Leiden University. We thank Camila Correa for help analysing snipshot merger trees. We thank the anonymous referee for constructive comments. We also thank Jarle Brinchmann, Rob Crain, Antonios Katsianis, Paola Popesso, and David Sobral for discussions and suggestions. We also thank the participants of the Lorentz Center workshop ‘A Decade of the Star-Forming Main Sequence’ held on 2017 September 4–8, for discussions and ideas. We have benefited from the public available programming language PYTHON, including the NUMPY, MATPLOTLIB, and SCIPY (Hunter 2007) packages and the TOPCAT analysis tool (Taylor 2013).","type":"journal_article","publication_identifier":{"issn":["0035-8711"],"eissn":["1365-2966"]},"oa_version":"Preprint","oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"last_name":"Calhau","full_name":"Calhau, João","first_name":"João"},{"last_name":"Sobral","first_name":"David","full_name":"Sobral, David"},{"last_name":"Santos","full_name":"Santos, Sérgio","first_name":"Sérgio"},{"first_name":"Jorryt J","full_name":"Matthee, Jorryt J","last_name":"Matthee","orcid":"0000-0003-2871-127X","id":"7439a258-f3c0-11ec-9501-9df22fe06720"},{"last_name":"Paulino-Afonso","full_name":"Paulino-Afonso, Ana","first_name":"Ana"},{"first_name":"Andra","full_name":"Stroe, Andra","last_name":"Stroe"},{"full_name":"Simmons, Brooke","first_name":"Brooke","last_name":"Simmons"},{"first_name":"Cassandra","full_name":"Barlow-Hall, Cassandra","last_name":"Barlow-Hall"},{"full_name":"Adams, Benjamin","first_name":"Benjamin","last_name":"Adams"}],"keyword":["Space and Planetary Science","Astronomy and Astrophysics","galaxies: active","galaxies: evolution","galaxies: high-redshift","quasars: supermassive black holes","galaxies: star formation","cosmology: observations","X-rays: galaxies"],"month":"04","issue":"3","day":"01","article_processing_charge":"No","quality_controlled":"1","language":[{"iso":"eng"}],"year":"2020","publication":"Monthly Notices of the Royal Astronomical Society","article_type":"original","intvolume":"       493","citation":{"ista":"Calhau J, Sobral D, Santos S, Matthee JJ, Paulino-Afonso A, Stroe A, Simmons B, Barlow-Hall C, Adams B. 2020. The X-ray and radio activity of typical and luminous Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population. Monthly Notices of the Royal Astronomical Society. 493(3), 3341–3362.","ama":"Calhau J, Sobral D, Santos S, et al. The X-ray and radio activity of typical and luminous Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population. <i>Monthly Notices of the Royal Astronomical Society</i>. 2020;493(3):3341-3362. doi:<a href=\"https://doi.org/10.1093/mnras/staa476\">10.1093/mnras/staa476</a>","ieee":"J. Calhau <i>et al.</i>, “The X-ray and radio activity of typical and luminous Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population,” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 493, no. 3. Oxford University Press, pp. 3341–3362, 2020.","short":"J. Calhau, D. Sobral, S. Santos, J.J. Matthee, A. Paulino-Afonso, A. Stroe, B. Simmons, C. Barlow-Hall, B. Adams, Monthly Notices of the Royal Astronomical Society 493 (2020) 3341–3362.","chicago":"Calhau, João, David Sobral, Sérgio Santos, Jorryt J Matthee, Ana Paulino-Afonso, Andra Stroe, Brooke Simmons, Cassandra Barlow-Hall, and Benjamin Adams. “The X-Ray and Radio Activity of Typical and Luminous Ly α Emitters from z ∼ 2 to z ∼ 6: Evidence for a Diverse, Evolving Population.” <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press, 2020. <a href=\"https://doi.org/10.1093/mnras/staa476\">https://doi.org/10.1093/mnras/staa476</a>.","apa":"Calhau, J., Sobral, D., Santos, S., Matthee, J. J., Paulino-Afonso, A., Stroe, A., … Adams, B. (2020). The X-ray and radio activity of typical and luminous Ly α emitters from z ∼ 2 to z ∼ 6: Evidence for a diverse, evolving population. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press. <a href=\"https://doi.org/10.1093/mnras/staa476\">https://doi.org/10.1093/mnras/staa476</a>","mla":"Calhau, João, et al. “The X-Ray and Radio Activity of Typical and Luminous Ly α Emitters from z ∼ 2 to z ∼ 6: Evidence for a Diverse, Evolving Population.” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 493, no. 3, Oxford University Press, 2020, pp. 3341–62, doi:<a href=\"https://doi.org/10.1093/mnras/staa476\">10.1093/mnras/staa476</a>."},"date_created":"2022-07-08T07:34:10Z","date_published":"2020-04-01T00:00:00Z","external_id":{"arxiv":["1909.11672"]},"arxiv":1}]