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IQUIST Young Researchers Seminar: “Developing Phase Slip Fluxonium Qubits," presented by Cheeranjeev Purmessur, Kou Group

Event Type
190 Engineering Sciences Building, 1101 W Springfield Ave, Urbana, IL 61801
Dec 7, 2022   12:00 - 12:50 pm  
Cheeranjeev Purmessur, Kou Group, Department of Physics, UIUC
Wolfgang Pfaff
Originating Calendar
IQUIST Young Researchers Seminar

Developing Phase Slip Fluxonium Qubits 

: The Josephson junction (JJ) is an essential component of superconducting qubits. They provide nonlinearity in transmon qubits and allow for tunneling of the energy barrier in fluxonium qubits. However, aluminum-based JJs have a low Tc (1.2 K), limiting the operating temperature to << 1 K and the frequency range of photons to << 70 GHz. In this talk, I will introduce thin films of disordered superconducting wires as an alternative to JJs. These disordered films have large intrinsic quality factors and thus could potentially lead to high coherence in superconducting qubits. I will focus on thin films made of titanium nitride (TiN), which relative to aluminum, has a large superconducting gap, allowing for a wider range in operating temperature and frequency space. Furthermore, I will demonstrate how JJs could be replaced in both the superinductance and phase slip components of the fluxonium qubit through the kinetic inductance and the phase slip phenomena in nanowires. Finally, I will describe our experimental progress in characterizing the quality of our TiN film and the nonlinearity of our superconducting nanowires. 

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