Variable Electrostatic Transformer: Controllable Coupling of Two Charge Qubits

2003/04/30 by D. V. Averin, Christoph Bruder, C. Bruder · 2 citations
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum and electron transport phenomena #Spectroscopy and Quantum Chemical Studies #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevlett.91.057003

published as Phys. Rev. Lett. 91, 057003 (2003). · final version, to appear in Phys. Rev. Lett

arxiv created 2003/07/28 · openalex publication_date 2003/07/30 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We propose and investigate a novel method for the controlled coupling of two Josephson charge qubits by means of a variable electrostatic transformer. The value of the coupling capacitance is given by the discretized curvature of the lowest energy band of a Josephson junction, which can be positive, negative, or zero. We calculate the charging diagram of the two-qubit system that reflects the transition from positive to negative through vanishing coupling. We also discuss how to implement a phase gate making use of the controllable coupling.

Citations

• Coherent control of macroscopic quantum states in a single-Cooper-pair box
• Gigahertz Electron Spin Manipulation Using Voltage-Controlled g-Tensor Modulation
• Quantum Manipulations of Small Josephson Junctions
• Coherent Quantum Dynamics of a Superconducting Flux Qubit
• Scalable Quantum Computing with Josephson Charge Qubits
• Josephson-junction qubits with controlled couplings
• RSFQ logic/memory family: a new Josephson-junction technology for sub-terahertz-clock-frequency digital systems

Cited by

• Interqubit coupling mediated by a high-excitation-energy quantum object
• Tunable coupling of qubits: Nonadiabatic corrections