BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:QSE Quantum Seminar - Novel Pockels materials beyond Lithium nioba te and barium titanate for quantum electro-optical applications & Hybrid T echnologies with high-performance superconducting circuits DTSTART:20250226T120000 DTEND:20250226T133000 DTSTAMP:20260525T203050Z UID:6f3cef541451125835f2f785a59a4389a02ff646b18b26e75eac8dee CATEGORIES:Conferences - Seminars DESCRIPTION:Christian Haffner\, Atsushi Noguchi\nPlease join us for the  QSE Center Quantum Seminar with Christian Haffner from IMEC\, who wi ll give the talk "Novel Pockels materials beyond Lithium niobate and bari um titanate for quantum electro-optical applications" and Atsushi Noguchi from University of Tokyo\, who will give the talk "Hybrid Technologies wi th high-performance superconducting circuits" on Wednesday February 26th.  \nLocation: BS 270.\n\nPizzas will be available before the seminar at 1 2:00. All PhDs\, postdocs\, students\, and PIs are welcome to join us.\n\n TITLE: Novel Pockels materials beyond Lithium niobate and barium titanate for quantum electro-optical applications & Hybrid Technologies with high -performance superconducting circuits\n\nABSTRACT:\n\n Quantum computers f ace many challenges towards upscaling the number of qubits and increasing their computational power. For superconducting qubits\, this is the radio frequency (RF) -bottleneck between the qubit processor inside the cryosta t and the room temperature control and readout electronics. And like for t heir classical counterparts\, hope lies in replacing the RF-links by optic al fibers\, resulting in a hybrid situation where RF-qubits will be used f or computation and optical qubits will serve for remote communication. How ever\, electro-optical (EO) transducers that parametrically amplify RF-qu bits directly to optical qubits with a unity efficiency have thus far rem ained elusive. Key to a unity efficiency are materials that feature low lo sses\, strong nonlinearities and that allow to squeeze down the electro-ma gnetic field to smallest volumes. Current research focuses on devices base d on opto-electro-mechanics or on lithium niobate devices - the classical workhorse of long-range optical communication. In this talk\, we discuss h igh-k strontium titanate as a potential new material that could provide no nlinearities larger than lithium niobate\, its unique challenges for EO-tr ansduction and our progress on thin-film integration.\n Quantum informatio n science has evolved with the discovery and proposal of promising applica tions and is now entering the phase of testing them using actual quantum h ardware. However\, currently available quantum systems are still vulnerabl e to environmental noise and energy loss. Hence\, implementing quantum err or correction [1] in a scalable approach is essential to demonstrate their potential and real-time error corrections beyond break-even have been rec ently demonstrated with superconducting quantum circuits [2\,3]. There is still a huge overhead toward large-scale fault tolerance quantum computing \, which can be suppressed by achieving ultra-small-error quantum manipula tion [4]. In addition to the advancements in quantum information science t hrough superconducting qubits\, the performance of superconducting circuit s has improved by several orders of magnitude over decades. These supercon ducting technologies are not only applicable to superconducting qubits but also to other types of quantum hardware\, contributing to the reduction o f error rates. \n   We investigated the high Q microwave resonator using epitaxial grown TiN film on silicon substrates [5]. Our two-dimensional m icrowave resonator reaches a quality factor of 10 million at the single ph oton level and 100 million at the high-power input\, which is limited by t he surface loss of the interface between the material. We also develop hig h Q membrane oscillators with the highly-stressed epitaxial TiN film\, whi ch can be an ultra-long life quantum memory of the superconducting qubit. We evaluated its quality factor as ~10 million with an optical interferome ter at 2 K. These technologies increase not only the performance of the su perconducting qubit\, but also other quantum systems like ion traps. Ion t rap quantum system is another promising candidate of the quantum system fo r quantum information processing. The ultra-precise quantum manipulations have been achieved with trapped ions and especially a fidelity of 99.97% h as been reported for a microwave-based two-qubit gate [6] by the strong ma gnetic RF/MW field gradient. We recently fabricated the ion trap chip inte grated with a high-Q superconducting resonator\, which can be applied to t he ion trap experiment [7]. A microwave current is amplified by the high-Q superconducting resonator\, and a power-efficient two-qubit gate will be achieved. We also discuss the other applications of the superconducting ci rcuits to other isolated quantum systems. \n  \n Reference: \n [1] S.  B. Bravyi and A. Y. Kitaev\, arXiv:9811052 (1998). \n [2] Google Qua ntum AI\, Nature 614\, 676 (2023). \n [3] V. V. Sivak\, A. Eickbusch\, B. Royer\, S. Singh\, I. Tsioutsios\, S. Ganjam\, A. Miano\, B. L. Brock\, A . Z. Ding\, L. Frunzio\, S. M. Girvin\, R. J. Schoelkopf & M. H. Devoret\, Nature 616\, 50 (2023). \n [4] A. G. Fowler\, M. Mariantoni\, J. M. Mart inis\, and A. N. Cleland\, Phys. Rev. A 86\, 032324 (2012) \n [5] R. Sun\ , K. Makise\, W. Qiu\, H. Terai and Z. Wang\, in IEEE Transactions on Appl ied Superconductivity\, 25\, 1 (2015). \n [6] C. M. Löschnauer\, J. Mosc a Toba\, A. C. Hughes\, S. A. King\, M. A. Weber\, R. Srinivas\, R. Matt\, R. Nourshargh\, D. T. C. Allcock\, C. J. Ballance\, C. Matthiesen\, M. Ma linowski\, T. P. Harty\, arXiv:2407.07694 (2024). \n [7] Y. Tsuchimoto\, I. Nakamura\, S. Shirai and A. Noguchi\, EPJ Quantum Technology 11\, 56 (2 024). \n\n\nBIO:\n\n Christian Haffner is a Principal Member of Technical Staff and the first one to receive IMEC’s tenure track. His tenure proj ect investigates the fundamental limits of electro-optical devices for cla ssical and quantum applications. In 2022\, he received an ERC starting gra nt to support this research. In 2019\, he joined the 5-year Branco-Weiss F ellowship program. He did his Postdoc research on nano-scale opto-mechanic al switches at NIST\, Gaithersburg and ETH\, Zurich. He earned his Ph.D. d egree from ETH Zurich in 2018\, which was recognized with the ETH Medal an d Hans-Eggenberger Prize. He received his B.Sc. and M.Sc. degree in electr ical engineering from the Karlsruhe Institute of Technology (Germany)in 20 12 and in 2013\, respectively.\n Atsushi Noguchi is Associate Professor at the University of Tokyo\, and Team Leader of Riken Center for Quantum Com puting. He received his Ph.D. for Ion Trap Quantum Technology from Osaka U niversity in 2013. After a postdoctoral fellowship at Osaka University in 2014\, he has working on hybrid quantum systems with superconducting circu its at RCAST\, the University of Tokyo\, since 2015. He has been an associ ate professor of the Department of Basic Science at the University of Toky o since 2019. He is also a Fellow of InaRIS at Inamori Institute of Scienc e from 2020\, and a Team Leader at RIKEN Center for Quantum Computing from 2021. \n LOCATION:BS 270 https://plan.epfl.ch/?room==BS%20270 STATUS:CONFIRMED END:VEVENT END:VCALENDAR