Quantum Devices and Circuits Using Hybrid Nanowires – QUADIC

Project Overview
This project will support a collaboration between researchers in the United States and France that will both explore and enhance the potential of nanowire-based devices for quantum information science. The project will design, create, and characterize nanowire-based quantum-limited nonlinear quantum circuits such as parametric amplifiers that leverage the unique features of the hybrid materials platform. The devices will offer unique operational advantages such as large gate-tunability exceeding 1 GHz, gains of up to 20 dB, dynamic bandwidth of order 40 MHz, and magnetic field compatibility up to 1 Tesla. The applications of these devices include pump-efficient quantum-limited amplification, as well as potential use in novel two-qubit gate schemes. Magnetic field compatibility offers opportunities for integration into spin qubit and future topological quantum computing platforms. Device design will be based on the unconventional Josephson effects such as non-inversion symmetric current-phase relations. Intrinsic spin-orbit interaction and large effective Landé g-factors in InAs will be used to induce strong third-order nonlinearities in Josephson inductive elements, realizing in a single junction the equivalent of quantum circuits such as the Superconducting Nonlinear Asymmetric Inductive eLement (SNAIL).
The project will operate as a rapid and tight feedback loop between collaborators in the US and France. InAs nanowires will be grown and studied at Institut Néel/CNRS and Pheliqs/CEA in Grenoble, France. Quantum devices will be fabricated and measured in Pittsburgh, while device and first principles theory will be done in France.

Intellectual Merit
The hybrid platform offers electric field tunability of Josephson characteristics which is a modality with potential for scaling quantum circuits. Quantum parametric amplifiers are prominently featured in schemes for quantum-limited detection, as well as coupling of distant quantum circuits. Nanowire quality metrics, such as defect-free, epitaxial growth are believed to directly translate into the performance of quantum devices.

Broader Impacts
The significance of this work for quantum technologies goes beyond new modalities for quantum circuits. Development of magnetic field-compatible superconducting quantum circuits impacts the domains of quantum dot spin qubits as well as topological quantum experiments. Research into the growth and characterization of hybrid nanowires benefits the Majorana search where crystal growth in the current bottleneck.
The program will train graduate students in the topics of quantum science and technology and prepare them for careers in quantum-related academia and industry. The project will facilitate bilateral internships, for US students in France, and vice versa, with the aim of enhancing their academic, research and cultural experience. The team has a track record of student exchanges in the framework of GIANT International Internship Program based in Grenoble. A conference on hybrid devices will be organized in Grenoble.