Controlling Superconducting Qubits

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Controlling the quantum state of very small devices is important for future technology. In particular, controlling the state of superconducting (SC) qubits (i.e., artificial atoms) offers the opportunity to study fundamental quantum mechanics and illuminating analogies with atomic physics. In addition, new forms of computing might be possible when controlling the quantum mechanical state of SC qubits. This research studies several aspects of the physics of SC qubits. Projects studied in this project include: (1) quantum computing (QC) schemes based on Josephson qubits coupled through nonclassical microwave fields; (2) switchable and scalable circuit designs involving inductive couplings, as opposed to the usual capacitor-based couplings for charge qubits; (3) circuits with a Current-Biased Josephson Junction (CBJJ) acting as a bus (a SC JJ qubit analog of the ion-trap QC set-up, with the CBJJ acting as the ?information bus? between qubits); (4) quantum tomography; (5) several properties of SC qubits inside a cavity (which we first proposed in 2001, and which was implemented experimentally in 2004) as well as how to generate single photons on demand by placing a SC JJ qubit inside a micro-cavity; (6) explore ways to generate an arbitrary superposition of photon states, including cat states, using SC JJ qubits. All of this while simultaneously interacting with experimentalists trying to implement these.