KIT (Karlsuher Institute für Technologie)

Ioan Pop

Ioan Pop is a researcher in quantum engineering, working on quantum superconducting microelectronic circuits with Josephson junctions, towards the goal of implementing quantum coherent hardware for information processing and ultra-sensitive detection. In particular, Ioan’s research group is interested in high characteristic impedance circuits, such as thin-film disordered superconductors and Josephson junction arrays, for the implementation of quantum detectors, amplifiers, and processors. In AvaQus, Ioan’s group is focusing on the implementation of high characteristic impedance qubits, with high coherence and control over the coupling, to be used for quantum annealing.

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Daria Gusenkova

Daria Gusenkova, PhD student in Ioan Pop's group at KIT, contributed to the AVaQus project during 2021. She designed, fabricated and measured a gradiometric fluxonium qubit which can be locked at the flux sweet spots by cooling it down in the appropriate magnetic field. Remarkably, Daria uncovered a destruction mechanism of trapped flux in superconducting quantum circuits. By monitoring the stability of the initialization at the sweet spot in the KIT laboratory, and together with our INFN collaborators in the underground laboratory of Gran Sasso, Italy, Daria demonstrated that ionizing radiation can lead to the collapse of persistent currents in flux qubits. These catastrophic events occur every hour in the above ground laboratory, and their amount is reduced by an order of magnitude in the underground facility.

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Patrick Winkel

From July 2020 to January 2022 Patrick Winkel worked in the group of Ioan Pop as post-doc. In the context of the AVaQus project, he was responsible for the design, fabrication, and characterization of high impedance generalized flux qubits using granular aluminum for their application in a multi-qubit quantum processor. He coordinated a team of master and PhD students to develop a two-qubit processor design based on a flip-chip integration technique. The goal was to engineer the energy spectra and coupling of the qubits for the requirements of AVaQus, and to study their coherence. At the same time, he realized a dispersive readout technique for persistent current states in flux qubits using superconducting quantum interference devices.

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Simon Geisert

Simon Geisert is a PhD student under supervision of Ioan Pop at the Institute for Quantum Materials and Technologies at Karlsruhe Institute of Technology (KIT), where he also studied physics and graduated his Masters in 2021. His scientific interests revolve around superconductivity and the physics of quantum information as well as the technical challenges that come along with the realisation of superconducting circuits. His work therefore has a strong emphasis on finding novel architectures for scalable circuit designs that preserve coherence and enable versatile controllability of individual circuit parts such as tunable qubit-qubit coupling, which is paramount to building a coherent quantum annealing device.

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Soeren Ihssen

Soeren studied Physics at the University of Heidelberg. For his Bachelor's thesis in Prof. Klingeler's group, he did research on lithium-ion batteries. For his Master's thesis in Prof. Kempf's group, he investigated the use of different types of superconducting resonators in microwave SQUID multiplexers. Soeren started his PhD at KIT on 1st October 2021 in the group of Ioan Pop. His goal is to design a modular quantum processor.

In his free time, Soeren likes to play football, since he was a professional goalkeeper for over a year. He also loves hiking and to go on long cycling trips all over Europe. Besides, he enjoys reading/watching science fiction books/series to relax from work.

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