--- _id: '12213' abstract: - lang: eng text: 'Motivated by properties-controlling potential of the strain, we investigate strain dependence of structure, electronic, and magnetic properties of Sr2IrO4 using complementary theoretical tools: ab-initio calculations, analytical approaches (rigid octahedra picture, Slater-Koster integrals), and extended t−J model. We find that strain affects both Ir-Ir distance and Ir-O-Ir angle, and the rigid octahedra picture is not relevant. Second, we find fundamentally different behavior for compressive and tensile strain. One remarkable feature is the formation of two subsets of bond- and orbital-dependent carriers, a compass-like model, under compression. This originates from the strain-induced renormalization of the Ir-O-Ir superexchange and O on-site energy. We also show that under compressive (tensile) strain, Fermi surface becomes highly dispersive (relatively flat). Already at a tensile strain of 1.5%, we observe spectral weight redistribution, with the low-energy band acquiring almost purely singlet character. These results can be directly compared with future experiments.' acknowledgement: E.M.P. thanks Eugenio Paris, Thorsten Schmitt, Krzysztof Wohlfeld, and other coauthors for an inspiring previous collaboration23, and is grateful to Gang Cao, Ambrose Seo, and Jungho Kim for insightful discussions. R.R. acknowledges helpful discussion with Sanjeev Kumar and Manuel Richter. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 754411. C.C.C. acknowledges support from the U.S. National Science Foundation Award No. DMR-2142801. article_number: '90' article_processing_charge: No article_type: original author: - first_name: Ekaterina full_name: Paerschke, Ekaterina id: 8275014E-6063-11E9-9B7F-6338E6697425 last_name: Paerschke orcid: 0000-0003-0853-8182 - first_name: Wei-Chih full_name: Chen, Wei-Chih last_name: Chen - first_name: Rajyavardhan full_name: Ray, Rajyavardhan last_name: Ray - first_name: Cheng-Chien full_name: Chen, Cheng-Chien last_name: Chen citation: ama: Paerschke E, Chen W-C, Ray R, Chen C-C. Evolution of electronic and magnetic properties of Sr₂IrO₄ under strain. npj Quantum Materials. 2022;7. doi:10.1038/s41535-022-00496-w apa: Paerschke, E., Chen, W.-C., Ray, R., & Chen, C.-C. (2022). Evolution of electronic and magnetic properties of Sr₂IrO₄ under strain. Npj Quantum Materials. Springer Nature. https://doi.org/10.1038/s41535-022-00496-w chicago: Paerschke, Ekaterina, Wei-Chih Chen, Rajyavardhan Ray, and Cheng-Chien Chen. “Evolution of Electronic and Magnetic Properties of Sr₂IrO₄ under Strain.” Npj Quantum Materials. Springer Nature, 2022. https://doi.org/10.1038/s41535-022-00496-w. ieee: E. Paerschke, W.-C. Chen, R. Ray, and C.-C. Chen, “Evolution of electronic and magnetic properties of Sr₂IrO₄ under strain,” npj Quantum Materials, vol. 7. Springer Nature, 2022. ista: Paerschke E, Chen W-C, Ray R, Chen C-C. 2022. Evolution of electronic and magnetic properties of Sr₂IrO₄ under strain. npj Quantum Materials. 7, 90. mla: Paerschke, Ekaterina, et al. “Evolution of Electronic and Magnetic Properties of Sr₂IrO₄ under Strain.” Npj Quantum Materials, vol. 7, 90, Springer Nature, 2022, doi:10.1038/s41535-022-00496-w. short: E. Paerschke, W.-C. Chen, R. Ray, C.-C. Chen, Npj Quantum Materials 7 (2022). date_created: 2023-01-16T09:46:01Z date_published: 2022-09-10T00:00:00Z date_updated: 2023-08-04T09:23:43Z day: '10' ddc: - '530' department: - _id: MiLe doi: 10.1038/s41535-022-00496-w ec_funded: 1 external_id: isi: - '000852381200003' file: - access_level: open_access checksum: d93b477b5b95c0d1b8f9fef90a81f565 content_type: application/pdf creator: dernst date_created: 2023-01-27T07:59:27Z date_updated: 2023-01-27T07:59:27Z file_id: '12414' file_name: 2022_NPJ_Paerschke.pdf file_size: 1852598 relation: main_file success: 1 file_date_updated: 2023-01-27T07:59:27Z has_accepted_license: '1' intvolume: ' 7' isi: 1 keyword: - Condensed Matter Physics - Electronic - Optical and Magnetic Materials language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '09' oa: 1 oa_version: Published Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: npj Quantum Materials publication_identifier: eissn: - 2397-4648 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: link: - relation: erratum url: https://doi.org/10.1038/s41535-022-00510-1 scopus_import: '1' status: public title: Evolution of electronic and magnetic properties of Sr₂IrO₄ under strain tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 7 year: '2022' ... --- _id: '12154' abstract: - lang: eng text: We review our theoretical results of the sound propagation in two-dimensional (2D) systems of ultracold fermionic and bosonic atoms. In the superfluid phase, characterized by the spontaneous symmetry breaking of the U(1) symmetry, there is the coexistence of first and second sound. In the case of weakly-interacting repulsive bosons, we model the recent measurements of the sound velocities of 39K atoms in 2D obtained in the weakly-interacting regime and around the Berezinskii–Kosterlitz–Thouless (BKT) superfluid-to-normal transition temperature. In particular, we perform a quite accurate computation of the superfluid density and show that it is reasonably consistent with the experimental results. For superfluid attractive fermions, we calculate the first and second sound velocities across the whole BCS-BEC crossover. In the low-temperature regime, we reproduce the recent measurements of first-sound speed with 6Li atoms. We also predict that there is mixing between sound modes only in the finite-temperature BEC regime. acknowledgement: "This research is partially supported by University of Padova, BIRD grant “Ultracold atoms\r\nin curved geometries”. KF is supported by Fondazione CARIPARO with a PhD fellowship. AT is\r\npartially supported by French National Research Agency ANR Grant Droplets N. ANR-19-CE30-0003-02. LS thanks Herwig Ott and Sandro Wimberger for their kind invitation to the\r\nInternational Workshop “Quantum Transport with ultracold atoms” (2022)." article_number: '2182' article_processing_charge: Yes article_type: original author: - first_name: Luca full_name: Salasnich, Luca last_name: Salasnich - first_name: Alberto full_name: Cappellaro, Alberto id: 9d13b3cb-30a2-11eb-80dc-f772505e8660 last_name: Cappellaro orcid: 0000-0001-6110-2359 - first_name: Koichiro full_name: Furutani, Koichiro last_name: Furutani - first_name: Andrea full_name: Tononi, Andrea last_name: Tononi - first_name: Giacomo full_name: Bighin, Giacomo id: 4CA96FD4-F248-11E8-B48F-1D18A9856A87 last_name: Bighin orcid: 0000-0001-8823-9777 citation: ama: Salasnich L, Cappellaro A, Furutani K, Tononi A, Bighin G. First and second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. 2022;14(10). doi:10.3390/sym14102182 apa: Salasnich, L., Cappellaro, A., Furutani, K., Tononi, A., & Bighin, G. (2022). First and second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. MDPI. https://doi.org/10.3390/sym14102182 chicago: Salasnich, Luca, Alberto Cappellaro, Koichiro Furutani, Andrea Tononi, and Giacomo Bighin. “First and Second Sound in Two-Dimensional Bosonic and Fermionic Superfluids.” Symmetry. MDPI, 2022. https://doi.org/10.3390/sym14102182. ieee: L. Salasnich, A. Cappellaro, K. Furutani, A. Tononi, and G. Bighin, “First and second sound in two-dimensional bosonic and fermionic superfluids,” Symmetry, vol. 14, no. 10. MDPI, 2022. ista: Salasnich L, Cappellaro A, Furutani K, Tononi A, Bighin G. 2022. First and second sound in two-dimensional bosonic and fermionic superfluids. Symmetry. 14(10), 2182. mla: Salasnich, Luca, et al. “First and Second Sound in Two-Dimensional Bosonic and Fermionic Superfluids.” Symmetry, vol. 14, no. 10, 2182, MDPI, 2022, doi:10.3390/sym14102182. short: L. Salasnich, A. Cappellaro, K. Furutani, A. Tononi, G. Bighin, Symmetry 14 (2022). date_created: 2023-01-12T12:08:31Z date_published: 2022-10-17T00:00:00Z date_updated: 2023-08-09T10:13:17Z day: '17' ddc: - '530' department: - _id: MiLe doi: 10.3390/sym14102182 external_id: isi: - '000875039200001' file: - access_level: open_access checksum: 9b6bd0e484834dd76d7b26e3c5fba8bd content_type: application/pdf creator: dernst date_created: 2023-01-24T10:56:12Z date_updated: 2023-01-24T10:56:12Z file_id: '12361' file_name: 2022_Symmetry_Salsnich.pdf file_size: 843723 relation: main_file success: 1 file_date_updated: 2023-01-24T10:56:12Z has_accepted_license: '1' intvolume: ' 14' isi: 1 issue: '10' keyword: - Physics and Astronomy (miscellaneous) - General Mathematics - Chemistry (miscellaneous) - Computer Science (miscellaneous) language: - iso: eng month: '10' oa: 1 oa_version: Published Version publication: Symmetry publication_identifier: issn: - 2073-8994 publication_status: published publisher: MDPI quality_controlled: '1' scopus_import: '1' status: public title: First and second sound in two-dimensional bosonic and fermionic superfluids tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2022' ... --- _id: '10759' abstract: - lang: eng text: In this Thesis, I study composite quantum impurities with variational techniques, both inspired by machine learning as well as fully analytic. I supplement this with exploration of other applications of machine learning, in particular artificial neural networks, in many-body physics. In Chapters 3 and 4, I study quasiparticle systems with variational approach. I derive a Hamiltonian describing the angulon quasiparticle in the presence of a magnetic field. I apply analytic variational treatment to this Hamiltonian. Then, I introduce a variational approach for non-additive systems, based on artificial neural networks. I exemplify this approach on the example of the polaron quasiparticle (Fröhlich Hamiltonian). In Chapter 5, I continue using artificial neural networks, albeit in a different setting. I apply artificial neural networks to detect phases from snapshots of two types physical systems. Namely, I study Monte Carlo snapshots of multilayer classical spin models as well as molecular dynamics maps of colloidal systems. The main type of networks that I use here are convolutional neural networks, known for their applicability to image data. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Wojciech full_name: Rzadkowski, Wojciech id: 48C55298-F248-11E8-B48F-1D18A9856A87 last_name: Rzadkowski orcid: 0000-0002-1106-4419 citation: ama: Rzadkowski W. Analytic and machine learning approaches to composite quantum impurities. 2022. doi:10.15479/at:ista:10759 apa: Rzadkowski, W. (2022). Analytic and machine learning approaches to composite quantum impurities. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:10759 chicago: Rzadkowski, Wojciech. “Analytic and Machine Learning Approaches to Composite Quantum Impurities.” Institute of Science and Technology Austria, 2022. https://doi.org/10.15479/at:ista:10759. ieee: W. Rzadkowski, “Analytic and machine learning approaches to composite quantum impurities,” Institute of Science and Technology Austria, 2022. ista: Rzadkowski W. 2022. Analytic and machine learning approaches to composite quantum impurities. Institute of Science and Technology Austria. mla: Rzadkowski, Wojciech. Analytic and Machine Learning Approaches to Composite Quantum Impurities. Institute of Science and Technology Austria, 2022, doi:10.15479/at:ista:10759. short: W. Rzadkowski, Analytic and Machine Learning Approaches to Composite Quantum Impurities, Institute of Science and Technology Austria, 2022. date_created: 2022-02-16T13:27:37Z date_published: 2022-02-21T00:00:00Z date_updated: 2024-02-28T13:01:59Z day: '21' ddc: - '530' degree_awarded: PhD department: - _id: GradSch - _id: MiLe doi: 10.15479/at:ista:10759 ec_funded: 1 file: - access_level: closed checksum: 0fc54ad1eaede879c665ac9b53c93e22 content_type: application/zip creator: wrzadkow date_created: 2022-02-21T13:58:16Z date_updated: 2022-02-22T07:20:12Z file_id: '10785' file_name: Rzadkowski_thesis_final_source.zip file_size: 17668233 relation: source_file - access_level: open_access checksum: 22d2d7af37ca31f6b1730c26cac7bced content_type: application/pdf creator: wrzadkow date_created: 2022-02-21T14:02:54Z date_updated: 2022-02-21T14:02:54Z file_id: '10786' file_name: Rzadkowski_thesis_final.pdf file_size: 13307331 relation: main_file success: 1 file_date_updated: 2022-02-22T07:20:12Z has_accepted_license: '1' language: - iso: eng month: '02' oa: 1 oa_version: Published Version page: '120' project: - _id: 2564DBCA-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '665385' name: International IST Doctoral Program publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '10762' relation: part_of_dissertation status: public - id: '8644' relation: part_of_dissertation status: public - id: '7956' relation: part_of_dissertation status: public - id: '415' relation: part_of_dissertation status: public status: public supervisor: - first_name: Mikhail full_name: Lemeshko, Mikhail id: 37CB05FA-F248-11E8-B48F-1D18A9856A87 last_name: Lemeshko orcid: 0000-0002-6990-7802 title: Analytic and machine learning approaches to composite quantum impurities type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2022' ... --- _id: '10585' abstract: - lang: eng text: Recently it was shown that anyons on the two-sphere naturally arise from a system of molecular impurities exchanging angular momentum with a many-particle bath (Phys. Rev. Lett. 126, 015301 (2021)). Here we further advance this approach and rigorously demonstrate that in the experimentally realized regime the lowest spectrum of two linear molecules immersed in superfluid helium corresponds to the spectrum of two anyons on the sphere. We develop the formalism within the framework of the recently experimentally observed angulon quasiparticle acknowledgement: D. Lundholm acknowledges financial support from the Göran Gustafsson Foundation (grant no. 1804). article_number: '106' article_processing_charge: Yes article_type: original author: - first_name: Morris full_name: Brooks, Morris id: B7ECF9FC-AA38-11E9-AC9A-0930E6697425 last_name: Brooks orcid: 0000-0002-6249-0928 - first_name: Mikhail full_name: Lemeshko, Mikhail id: 37CB05FA-F248-11E8-B48F-1D18A9856A87 last_name: Lemeshko orcid: 0000-0002-6990-7802 - first_name: Douglas full_name: Lundholm, Douglas last_name: Lundholm - first_name: Enderalp full_name: Yakaboylu, Enderalp id: 38CB71F6-F248-11E8-B48F-1D18A9856A87 last_name: Yakaboylu orcid: 0000-0001-5973-0874 citation: ama: Brooks M, Lemeshko M, Lundholm D, Yakaboylu E. Emergence of anyons on the two-sphere in molecular impurities. Atoms. 2021;9(4). doi:10.3390/atoms9040106 apa: Brooks, M., Lemeshko, M., Lundholm, D., & Yakaboylu, E. (2021). Emergence of anyons on the two-sphere in molecular impurities. Atoms. MDPI. https://doi.org/10.3390/atoms9040106 chicago: Brooks, Morris, Mikhail Lemeshko, Douglas Lundholm, and Enderalp Yakaboylu. “Emergence of Anyons on the Two-Sphere in Molecular Impurities.” Atoms. MDPI, 2021. https://doi.org/10.3390/atoms9040106. ieee: M. Brooks, M. Lemeshko, D. Lundholm, and E. Yakaboylu, “Emergence of anyons on the two-sphere in molecular impurities,” Atoms, vol. 9, no. 4. MDPI, 2021. ista: Brooks M, Lemeshko M, Lundholm D, Yakaboylu E. 2021. Emergence of anyons on the two-sphere in molecular impurities. Atoms. 9(4), 106. mla: Brooks, Morris, et al. “Emergence of Anyons on the Two-Sphere in Molecular Impurities.” Atoms, vol. 9, no. 4, 106, MDPI, 2021, doi:10.3390/atoms9040106. short: M. Brooks, M. Lemeshko, D. Lundholm, E. Yakaboylu, Atoms 9 (2021). date_created: 2022-01-02T23:01:33Z date_published: 2021-12-02T00:00:00Z date_updated: 2023-06-15T14:51:49Z day: '02' ddc: - '530' department: - _id: MiLe - _id: RoSe doi: 10.3390/atoms9040106 external_id: arxiv: - '2108.06966' file: - access_level: open_access checksum: d0e44b95f36c9e06724f66832af0f8c3 content_type: application/pdf creator: alisjak date_created: 2022-01-03T10:15:05Z date_updated: 2022-01-03T10:15:05Z file_id: '10592' file_name: 2021_Atoms_Brooks.pdf file_size: 303070 relation: main_file success: 1 file_date_updated: 2022-01-03T10:15:05Z has_accepted_license: '1' intvolume: ' 9' issue: '4' keyword: - anyons - quasiparticles - Quantum Hall Effect - topological states of matter language: - iso: eng month: '12' oa: 1 oa_version: Published Version publication: Atoms publication_identifier: eissn: - 2218-2004 publication_status: published publisher: MDPI quality_controlled: '1' scopus_import: '1' status: public title: Emergence of anyons on the two-sphere in molecular impurities tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 9 year: '2021' ... --- _id: '8816' abstract: - lang: eng text: Area-dependent quantum field theory is a modification of two-dimensional topological quantum field theory, where one equips each connected component of a bordism with a positive real number—interpreted as area—which behaves additively under glueing. As opposed to topological theories, in area-dependent theories the state spaces can be infinite-dimensional. We introduce the notion of regularised Frobenius algebras in Hilbert spaces and show that area-dependent theories are in one-to-one correspondence to commutative regularised Frobenius algebras. We also provide a state sum construction for area-dependent theories. Our main example is two-dimensional Yang–Mills theory with compact gauge group, which we treat in detail. acknowledgement: The authors thank Yuki Arano, Nils Carqueville, Alexei Davydov, Reiner Lauterbach, Pau Enrique Moliner, Chris Heunen, André Henriques, Ehud Meir, Catherine Meusburger, Gregor Schaumann, Richard Szabo and Stefan Wagner for helpful discussions and comments. We also thank the referees for their detailed comments which significantly improved the exposition of this paper. LS is supported by the DFG Research Training Group 1670 “Mathematics Inspired by String Theory and Quantum Field Theory”. Open access funding provided by Institute of Science and Technology (IST Austria). article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Ingo full_name: Runkel, Ingo last_name: Runkel - first_name: Lorant full_name: Szegedy, Lorant id: 7943226E-220E-11EA-94C7-D59F3DDC885E last_name: Szegedy orcid: 0000-0003-2834-5054 citation: ama: Runkel I, Szegedy L. Area-dependent quantum field theory. Communications in Mathematical Physics. 2021;381(1):83–117. doi:10.1007/s00220-020-03902-1 apa: Runkel, I., & Szegedy, L. (2021). Area-dependent quantum field theory. Communications in Mathematical Physics. Springer Nature. https://doi.org/10.1007/s00220-020-03902-1 chicago: Runkel, Ingo, and Lorant Szegedy. “Area-Dependent Quantum Field Theory.” Communications in Mathematical Physics. Springer Nature, 2021. https://doi.org/10.1007/s00220-020-03902-1. ieee: I. Runkel and L. Szegedy, “Area-dependent quantum field theory,” Communications in Mathematical Physics, vol. 381, no. 1. Springer Nature, pp. 83–117, 2021. ista: Runkel I, Szegedy L. 2021. Area-dependent quantum field theory. Communications in Mathematical Physics. 381(1), 83–117. mla: Runkel, Ingo, and Lorant Szegedy. “Area-Dependent Quantum Field Theory.” Communications in Mathematical Physics, vol. 381, no. 1, Springer Nature, 2021, pp. 83–117, doi:10.1007/s00220-020-03902-1. short: I. Runkel, L. Szegedy, Communications in Mathematical Physics 381 (2021) 83–117. date_created: 2020-11-29T23:01:17Z date_published: 2021-01-01T00:00:00Z date_updated: 2023-08-04T11:13:35Z day: '01' ddc: - '510' department: - _id: MiLe doi: 10.1007/s00220-020-03902-1 external_id: isi: - '000591139000001' file: - access_level: open_access checksum: 6f451f9c2b74bedbc30cf884a3e02670 content_type: application/pdf creator: dernst date_created: 2021-02-03T15:00:30Z date_updated: 2021-02-03T15:00:30Z file_id: '9081' file_name: 2021_CommMathPhys_Runkel.pdf file_size: 790526 relation: main_file success: 1 file_date_updated: 2021-02-03T15:00:30Z has_accepted_license: '1' intvolume: ' 381' isi: 1 issue: '1' language: - iso: eng month: '01' oa: 1 oa_version: Published Version page: 83–117 project: - _id: B67AFEDC-15C9-11EA-A837-991A96BB2854 name: IST Austria Open Access Fund publication: Communications in Mathematical Physics publication_identifier: eissn: - '14320916' issn: - '00103616' publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Area-dependent quantum field theory tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 381 year: '2021' ...