--- _id: '14553' abstract: - lang: eng text: Quantum state tomography is an essential component of modern quantum technology. In application to continuous-variable harmonic-oscillator systems, such as the electromagnetic field, existing tomography methods typically reconstruct the state in discrete bases, and are hence limited to states with relatively low amplitudes and energies. Here, we overcome this limitation by utilizing a feed-forward neural network to obtain the density matrix directly in the continuous position basis. An important benefit of our approach is the ability to choose specific regions in the phase space for detailed reconstruction. This results in a relatively slow scaling of the amount of resources required for the reconstruction with the state amplitude, and hence allows us to dramatically increase the range of amplitudes accessible with our method. article_number: '042430' article_processing_charge: No article_type: original author: - first_name: Ekaterina full_name: Fedotova, Ekaterina id: c1bea5e1-878e-11ee-9dff-d7404e4422ab last_name: Fedotova orcid: 0000-0001-7242-015X - first_name: Nikolai full_name: Kuznetsov, Nikolai last_name: Kuznetsov - first_name: Egor full_name: Tiunov, Egor last_name: Tiunov - first_name: A. E. full_name: Ulanov, A. E. last_name: Ulanov - first_name: A. I. full_name: Lvovsky, A. I. last_name: Lvovsky citation: ama: Fedotova E, Kuznetsov N, Tiunov E, Ulanov AE, Lvovsky AI. Continuous-variable quantum tomography of high-amplitude states. Physical Review A. 2023;108(4). doi:10.1103/PhysRevA.108.042430 apa: Fedotova, E., Kuznetsov, N., Tiunov, E., Ulanov, A. E., & Lvovsky, A. I. (2023). Continuous-variable quantum tomography of high-amplitude states. Physical Review A. American Physical Society. https://doi.org/10.1103/PhysRevA.108.042430 chicago: Fedotova, Ekaterina, Nikolai Kuznetsov, Egor Tiunov, A. E. Ulanov, and A. I. Lvovsky. “Continuous-Variable Quantum Tomography of High-Amplitude States.” Physical Review A. American Physical Society, 2023. https://doi.org/10.1103/PhysRevA.108.042430. ieee: E. Fedotova, N. Kuznetsov, E. Tiunov, A. E. Ulanov, and A. I. Lvovsky, “Continuous-variable quantum tomography of high-amplitude states,” Physical Review A, vol. 108, no. 4. American Physical Society, 2023. ista: Fedotova E, Kuznetsov N, Tiunov E, Ulanov AE, Lvovsky AI. 2023. Continuous-variable quantum tomography of high-amplitude states. Physical Review A. 108(4), 042430. mla: Fedotova, Ekaterina, et al. “Continuous-Variable Quantum Tomography of High-Amplitude States.” Physical Review A, vol. 108, no. 4, 042430, American Physical Society, 2023, doi:10.1103/PhysRevA.108.042430. short: E. Fedotova, N. Kuznetsov, E. Tiunov, A.E. Ulanov, A.I. Lvovsky, Physical Review A 108 (2023). date_created: 2023-11-19T23:00:54Z date_published: 2023-10-30T00:00:00Z date_updated: 2023-11-20T10:26:51Z day: '30' department: - _id: JoFi doi: 10.1103/PhysRevA.108.042430 external_id: arxiv: - '2212.07406' intvolume: ' 108' issue: '4' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.48550/arXiv.2212.07406 month: '10' oa: 1 oa_version: Preprint publication: Physical Review A publication_identifier: eissn: - 2469-9934 issn: - 2469-9926 publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Continuous-variable quantum tomography of high-amplitude states type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 108 year: '2023' ... --- _id: '13227' abstract: - lang: eng text: Currently available quantum processors are dominated by noise, which severely limits their applicability and motivates the search for new physical qubit encodings. In this work, we introduce the inductively shunted transmon, a weakly flux-tunable superconducting qubit that offers charge offset protection for all levels and a 20-fold reduction in flux dispersion compared to the state-of-the-art resulting in a constant coherence over a full flux quantum. The parabolic confinement provided by the inductive shunt as well as the linearity of the geometric superinductor facilitates a high-power readout that resolves quantum jumps with a fidelity and QND-ness of >90% and without the need for a Josephson parametric amplifier. Moreover, the device reveals quantum tunneling physics between the two prepared fluxon ground states with a measured average decay time of up to 3.5 h. In the future, fast time-domain control of the transition matrix elements could offer a new path forward to also achieve full qubit control in the decay-protected fluxon basis. acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: The authors thank J. Koch for discussions and support with the scQubits python package, I. Rozhansky and A. Poddubny for important insights into photon-assisted tunneling, S. Barzanjeh and G. Arnold for theory, E. Redchenko, S. Pepic, the MIBA workshop and the IST nanofabrication facility for technical contributions, as well as L. Drmic, P. Zielinski and R. Sett for software development. We acknowledge the prompt support of Quantum Machines to implement active state preparation with their OPX+. This work was supported by a NOMIS foundation research grant (J.F.), the Austrian Science Fund (FWF) through BeyondC F7105 (J.F.) and IST Austria. article_number: '3968' article_processing_charge: No article_type: original author: - first_name: Farid full_name: Hassani, Farid id: 2AED110C-F248-11E8-B48F-1D18A9856A87 last_name: Hassani orcid: 0000-0001-6937-5773 - first_name: Matilda full_name: Peruzzo, Matilda id: 3F920B30-F248-11E8-B48F-1D18A9856A87 last_name: Peruzzo orcid: 0000-0002-3415-4628 - first_name: Lucky full_name: Kapoor, Lucky id: 84b9700b-15b2-11ec-abd3-831089e67615 last_name: Kapoor - first_name: Andrea full_name: Trioni, Andrea id: 42F71B44-F248-11E8-B48F-1D18A9856A87 last_name: Trioni - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: Hassani F, Peruzzo M, Kapoor L, Trioni A, Zemlicka M, Fink JM. Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nature Communications. 2023;14. doi:10.1038/s41467-023-39656-2 apa: Hassani, F., Peruzzo, M., Kapoor, L., Trioni, A., Zemlicka, M., & Fink, J. M. (2023). Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-023-39656-2 chicago: Hassani, Farid, Matilda Peruzzo, Lucky Kapoor, Andrea Trioni, Martin Zemlicka, and Johannes M Fink. “Inductively Shunted Transmons Exhibit Noise Insensitive Plasmon States and a Fluxon Decay Exceeding 3 Hours.” Nature Communications. Springer Nature, 2023. https://doi.org/10.1038/s41467-023-39656-2. ieee: F. Hassani, M. Peruzzo, L. Kapoor, A. Trioni, M. Zemlicka, and J. M. Fink, “Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours,” Nature Communications, vol. 14. Springer Nature, 2023. ista: Hassani F, Peruzzo M, Kapoor L, Trioni A, Zemlicka M, Fink JM. 2023. Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours. Nature Communications. 14, 3968. mla: Hassani, Farid, et al. “Inductively Shunted Transmons Exhibit Noise Insensitive Plasmon States and a Fluxon Decay Exceeding 3 Hours.” Nature Communications, vol. 14, 3968, Springer Nature, 2023, doi:10.1038/s41467-023-39656-2. short: F. Hassani, M. Peruzzo, L. Kapoor, A. Trioni, M. Zemlicka, J.M. Fink, Nature Communications 14 (2023). date_created: 2023-07-16T22:01:08Z date_published: 2023-07-05T00:00:00Z date_updated: 2023-12-13T11:32:25Z day: '05' ddc: - '530' department: - _id: JoFi doi: 10.1038/s41467-023-39656-2 external_id: isi: - '001024729900009' pmid: - '37407570' file: - access_level: open_access checksum: a85773b5fe23516f60f7d5d31b55c200 content_type: application/pdf creator: dernst date_created: 2023-07-18T08:43:07Z date_updated: 2023-07-18T08:43:07Z file_id: '13248' file_name: 2023_NatureComm_Hassani.pdf file_size: 2899592 relation: main_file success: 1 file_date_updated: 2023-07-18T08:43:07Z has_accepted_license: '1' intvolume: ' 14' isi: 1 language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '07' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 26927A52-B435-11E9-9278-68D0E5697425 call_identifier: FWF grant_number: F07105 name: Integrating superconducting quantum circuits - _id: 2622978C-B435-11E9-9278-68D0E5697425 name: Hybrid Semiconductor - Superconductor Quantum Devices publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Inductively shunted transmons exhibit noise insensitive plasmon states and a fluxon decay exceeding 3 hours 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: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2023' ... --- _id: '14872' abstract: - lang: eng text: We entangled microwave and optical photons for the first time as verified by a measured two-mode vacuum squeezing of 0.7 dB. This electro-optic entanglement is the key resource needed to connect cryogenic quantum circuits. article_number: LM1F.3 article_processing_charge: No author: - first_name: Rishabh full_name: Sahu, Rishabh id: 47D26E34-F248-11E8-B48F-1D18A9856A87 last_name: Sahu orcid: 0000-0001-6264-2162 - first_name: Liu full_name: Qiu, Liu last_name: Qiu - first_name: William J full_name: Hease, William J id: 29705398-F248-11E8-B48F-1D18A9856A87 last_name: Hease orcid: 0000-0001-9868-2166 - first_name: Georg M full_name: Arnold, Georg M id: 3770C838-F248-11E8-B48F-1D18A9856A87 last_name: Arnold orcid: 0000-0003-1397-7876 - first_name: Yuri full_name: Minoguchi, Yuri last_name: Minoguchi - first_name: Peter full_name: Rabl, Peter last_name: Rabl - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X citation: ama: 'Sahu R, Qiu L, Hease WJ, et al. Entangling microwaves and telecom wavelength light. In: Frontiers in Optics + Laser Science 2023. Optica Publishing Group; 2023. doi:10.1364/ls.2023.lm1f.3' apa: 'Sahu, R., Qiu, L., Hease, W. J., Arnold, G. M., Minoguchi, Y., Rabl, P., & Fink, J. M. (2023). Entangling microwaves and telecom wavelength light. In Frontiers in Optics + Laser Science 2023. Tacoma, WA, United States: Optica Publishing Group. https://doi.org/10.1364/ls.2023.lm1f.3' chicago: Sahu, Rishabh, Liu Qiu, William J Hease, Georg M Arnold, Yuri Minoguchi, Peter Rabl, and Johannes M Fink. “Entangling Microwaves and Telecom Wavelength Light.” In Frontiers in Optics + Laser Science 2023. Optica Publishing Group, 2023. https://doi.org/10.1364/ls.2023.lm1f.3. ieee: R. Sahu et al., “Entangling microwaves and telecom wavelength light,” in Frontiers in Optics + Laser Science 2023, Tacoma, WA, United States, 2023. ista: Sahu R, Qiu L, Hease WJ, Arnold GM, Minoguchi Y, Rabl P, Fink JM. 2023. Entangling microwaves and telecom wavelength light. Frontiers in Optics + Laser Science 2023. Laser Science, LM1F.3. mla: Sahu, Rishabh, et al. “Entangling Microwaves and Telecom Wavelength Light.” Frontiers in Optics + Laser Science 2023, LM1F.3, Optica Publishing Group, 2023, doi:10.1364/ls.2023.lm1f.3. short: R. Sahu, L. Qiu, W.J. Hease, G.M. Arnold, Y. Minoguchi, P. Rabl, J.M. Fink, in:, Frontiers in Optics + Laser Science 2023, Optica Publishing Group, 2023. conference: end_date: 2023-10-12 location: Tacoma, WA, United States name: Laser Science start_date: 2023-10-09 date_created: 2024-01-22T12:29:41Z date_published: 2023-10-01T00:00:00Z date_updated: 2024-01-24T08:43:28Z day: '01' department: - _id: JoFi doi: 10.1364/ls.2023.lm1f.3 language: - iso: eng month: '10' oa_version: None publication: Frontiers in Optics + Laser Science 2023 publication_identifier: isbn: - '9781957171296' publication_status: published publisher: Optica Publishing Group quality_controlled: '1' status: public title: Entangling microwaves and telecom wavelength light type: conference user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 year: '2023' ... --- _id: '14032' abstract: - lang: eng text: Arrays of Josephson junctions are governed by a competition between superconductivity and repulsive Coulomb interactions, and are expected to exhibit diverging low-temperature resistance when interactions exceed a critical level. Here we report a study of the transport and microwave response of Josephson arrays with interactions exceeding this level. Contrary to expectations, we observe that the array resistance drops dramatically as the temperature is decreased—reminiscent of superconducting behaviour—and then saturates at low temperature. Applying a magnetic field, we eventually observe a transition to a highly resistive regime. These observations can be understood within a theoretical picture that accounts for the effect of thermal fluctuations on the insulating phase. On the basis of the agreement between experiment and theory, we suggest that apparent superconductivity in our Josephson arrays arises from melting the zero-temperature insulator. acknowledged_ssus: - _id: M-Shop - _id: NanoFab acknowledgement: We thank D. Haviland, J. Pekola, C. Ciuti, A. Bubis and A. Shnirman for helpful feedback on the paper. This research was supported by the Scientific Service Units of IST Austria through resources provided by the MIBA Machine Shop and the Nanofabrication Facility. Work supported by the Austrian FWF grant P33692-N (S.M., J.S. and A.P.H.), the European Union’s Horizon 2020 Research and Innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 754411 (J.S.) and a NOMIS foundation research grant (J.M.F. and A.P.H.). article_processing_charge: Yes (in subscription journal) article_type: original author: - first_name: Soham full_name: Mukhopadhyay, Soham id: FDE60288-A89D-11E9-947F-1AF6E5697425 last_name: Mukhopadhyay - first_name: Jorden L full_name: Senior, Jorden L id: 5479D234-2D30-11EA-89CC-40953DDC885E last_name: Senior orcid: 0000-0002-0672-9295 - first_name: Jaime full_name: Saez Mollejo, Jaime id: e0390f72-f6e0-11ea-865d-862393336714 last_name: Saez Mollejo - first_name: Denise full_name: Puglia, Denise id: 4D495994-AE37-11E9-AC72-31CAE5697425 last_name: Puglia orcid: 0000-0003-1144-2763 - first_name: Martin full_name: Zemlicka, Martin id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87 last_name: Zemlicka - first_name: Johannes M full_name: Fink, Johannes M id: 4B591CBA-F248-11E8-B48F-1D18A9856A87 last_name: Fink orcid: 0000-0001-8112-028X - first_name: Andrew P full_name: Higginbotham, Andrew P id: 4AD6785A-F248-11E8-B48F-1D18A9856A87 last_name: Higginbotham orcid: 0000-0003-2607-2363 citation: ama: Mukhopadhyay S, Senior JL, Saez Mollejo J, et al. Superconductivity from a melted insulator in Josephson junction arrays. Nature Physics. 2023;19:1630-1635. doi:10.1038/s41567-023-02161-w apa: Mukhopadhyay, S., Senior, J. L., Saez Mollejo, J., Puglia, D., Zemlicka, M., Fink, J. M., & Higginbotham, A. P. (2023). Superconductivity from a melted insulator in Josephson junction arrays. Nature Physics. Springer Nature. https://doi.org/10.1038/s41567-023-02161-w chicago: Mukhopadhyay, Soham, Jorden L Senior, Jaime Saez Mollejo, Denise Puglia, Martin Zemlicka, Johannes M Fink, and Andrew P Higginbotham. “Superconductivity from a Melted Insulator in Josephson Junction Arrays.” Nature Physics. Springer Nature, 2023. https://doi.org/10.1038/s41567-023-02161-w. ieee: S. Mukhopadhyay et al., “Superconductivity from a melted insulator in Josephson junction arrays,” Nature Physics, vol. 19. Springer Nature, pp. 1630–1635, 2023. ista: Mukhopadhyay S, Senior JL, Saez Mollejo J, Puglia D, Zemlicka M, Fink JM, Higginbotham AP. 2023. Superconductivity from a melted insulator in Josephson junction arrays. Nature Physics. 19, 1630–1635. mla: Mukhopadhyay, Soham, et al. “Superconductivity from a Melted Insulator in Josephson Junction Arrays.” Nature Physics, vol. 19, Springer Nature, 2023, pp. 1630–35, doi:10.1038/s41567-023-02161-w. short: S. Mukhopadhyay, J.L. Senior, J. Saez Mollejo, D. Puglia, M. Zemlicka, J.M. Fink, A.P. Higginbotham, Nature Physics 19 (2023) 1630–1635. date_created: 2023-08-11T07:41:17Z date_published: 2023-11-01T00:00:00Z date_updated: 2024-01-29T11:27:49Z day: '01' ddc: - '530' department: - _id: GradSch - _id: AnHi - _id: JoFi doi: 10.1038/s41567-023-02161-w ec_funded: 1 external_id: isi: - '001054563800006' file: - access_level: open_access checksum: 1fc86d71bfbf836e221c1e925343adc5 content_type: application/pdf creator: dernst date_created: 2024-01-29T11:25:38Z date_updated: 2024-01-29T11:25:38Z file_id: '14899' file_name: 2023_NaturePhysics_Mukhopadhyay.pdf file_size: 1977706 relation: main_file success: 1 file_date_updated: 2024-01-29T11:25:38Z has_accepted_license: '1' intvolume: ' 19' isi: 1 keyword: - General Physics and Astronomy language: - iso: eng month: '11' oa: 1 oa_version: Published Version page: 1630-1635 project: - _id: 0aa3608a-070f-11eb-9043-e9cd8a2bd931 grant_number: P33692 name: Cavity electromechanics across a quantum phase transition - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships - _id: eb9b30ac-77a9-11ec-83b8-871f581d53d2 name: Protected states of quantum matter - _id: bd5b4ec5-d553-11ed-ba76-a6eedb083344 name: Protected states of quantum matter publication: Nature Physics publication_identifier: eissn: - 1745-2481 issn: - 1745-2473 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Superconductivity from a melted insulator in Josephson junction arrays 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: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 19 year: '2023' ... --- _id: '14489' abstract: - lang: eng text: Microwave-optics entanglement is a vital component for building hybrid quantum networks. Here, a new mechanism for preparing stationary entanglement between microwave and optical cavity fields in a cavity optomagnomechanical system is proposed. It consists of a magnon mode in a ferrimagnetic crystal that couples directly to a microwave cavity mode via the magnetic dipole interaction and indirectly to an optical cavity through the deformation displacement of the crystal. The mechanical displacement is induced by the magnetostrictive force and coupled to the optical cavity via radiation pressure. Both the opto- and magnomechanical couplings are dispersive. Magnon–phonon entanglement is created via magnomechanical parametric down-conversion, which is further distributed to optical and microwave photons via simultaneous optomechanical beamsplitter interaction and electromagnonic state-swap interaction, yielding stationary microwave-optics entanglement. The microwave-optics entanglement is robust against thermal noise, which will find broad potential applications in quantum networks and quantum information processing with hybrid quantum systems. acknowledgement: This work was supported by the National Key Research and Development Program of China (Grant no. 2022YFA1405200), the National Natural Science Foundation of China (Nos. 92265202), and the European Research Council (ERC CoG Q-ECHOS, 101001005). article_number: '2200866' article_processing_charge: No article_type: original author: - first_name: Zhi Yuan full_name: Fan, Zhi Yuan last_name: Fan - first_name: Liu full_name: Qiu, Liu id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac last_name: Qiu orcid: 0000-0003-4345-4267 - first_name: Simon full_name: Gröblacher, Simon last_name: Gröblacher - first_name: Jie full_name: Li, Jie last_name: Li citation: ama: Fan ZY, Qiu L, Gröblacher S, Li J. Microwave-optics entanglement via cavity optomagnomechanics. Laser and Photonics Reviews. 2023;17(12). doi:10.1002/lpor.202200866 apa: Fan, Z. Y., Qiu, L., Gröblacher, S., & Li, J. (2023). Microwave-optics entanglement via cavity optomagnomechanics. Laser and Photonics Reviews. Wiley. https://doi.org/10.1002/lpor.202200866 chicago: Fan, Zhi Yuan, Liu Qiu, Simon Gröblacher, and Jie Li. “Microwave-Optics Entanglement via Cavity Optomagnomechanics.” Laser and Photonics Reviews. Wiley, 2023. https://doi.org/10.1002/lpor.202200866. ieee: Z. Y. Fan, L. Qiu, S. Gröblacher, and J. Li, “Microwave-optics entanglement via cavity optomagnomechanics,” Laser and Photonics Reviews, vol. 17, no. 12. Wiley, 2023. ista: Fan ZY, Qiu L, Gröblacher S, Li J. 2023. Microwave-optics entanglement via cavity optomagnomechanics. Laser and Photonics Reviews. 17(12), 2200866. mla: Fan, Zhi Yuan, et al. “Microwave-Optics Entanglement via Cavity Optomagnomechanics.” Laser and Photonics Reviews, vol. 17, no. 12, 2200866, Wiley, 2023, doi:10.1002/lpor.202200866. short: Z.Y. Fan, L. Qiu, S. Gröblacher, J. Li, Laser and Photonics Reviews 17 (2023). date_created: 2023-11-05T23:00:54Z date_published: 2023-12-01T00:00:00Z date_updated: 2024-01-30T14:36:42Z day: '01' department: - _id: JoFi doi: 10.1002/lpor.202200866 external_id: arxiv: - '2208.10703' intvolume: ' 17' issue: '12' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.48550/arXiv.2208.10703 month: '12' oa: 1 oa_version: Preprint publication: Laser and Photonics Reviews publication_identifier: eissn: - 1863-8899 issn: - 1863-8880 publication_status: published publisher: Wiley quality_controlled: '1' scopus_import: '1' status: public title: Microwave-optics entanglement via cavity optomagnomechanics type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 17 year: '2023' ...