The superconducting quantum computing architecture has seen rapid improvements over the last two decades. However, the coherence time of superconducting qubits is limited by unknown noise sources presumably existent at the interface between the insulator and the superconducting film. Carbon nanotubes (CNTs) are a promising material for use in Josephson-Junctions (JJs) given their unique properties, such as high electrical conductivity, pristine surface, inherent nanoscale dimension, and silicon-compatible processing. In this project, we are building gate-controlled JJs composed of CNT thin films (down-to-monolayer) positioned between two superconducting electrodes to act as a promising superconducting qubit for quantum computers. Aside from gate-controllability, this approach offers superb interface engineering capability, small integration footprint, and high-temperature operation. We expect the CNT film – JJ superconducting qubit will achieve superior performance relative to current state-of-the-art JJs and enable the development of scalable superconducting computation with extensions to arrays of CNT-JJs coupled to microwave and optical photon-waveguides.
Figure 1. Cooper pairs interacting with gate-controlled Jospehson-Junctions composed of CNT thin films
Inverse Photoemission Spectroscopy of Quantum Materials
Summary Quantum materials that exhibit strong electron correlations lead to phenomena, such as superconductivity and topologically protected states, that are important for quantum computation, sensing, and other applications. For example, we may utilize symmetry protected topological states to make qubits that are robust against decoherence, while advances in high temperature superconductors may significantly reduce […]
September 20, 2018
Distributing Multimode Entanglement with Microwave Photons
Microwaves have enabled numerous classical technologies, in part because they propagate through air with little energy loss.
March 6, 2017
Ultrafast Dynamical Studies of Valley-Based Qubits
Summary As monolayers, transition metal dichalcogenides (TMDCs) – such as tungsten diselenide (WSe2) – become direct-bandgap semiconductors capable of emitting light. Compared to conventional direct-bandgap semiconductors, such as III-V semiconductors like GaAs, excitons (quasiparticles made of an electron hole bound with an electron) and single-layer TMDCs (SL-TMDCs) have much stronger binding energy. Excitons and […]
June 29, 2018
Cryo-CMOS to Control and Operate 2D Fault-Tolerant Qubit Network
Summary Large-scale, fault-tolerant quantum computation requires precise and stable control of individual qubits. This project will use complementary metal-oxide-semiconductor (CMOS) technology to provide a cost-effective scalable platform for reliable and high-density control infrastructure for silicon spin qubits. We will use sub-micron CMOS technology to address device and circuit-level challenges and explore the integration of […]
June 14, 2018