2005/09/22 by Kyungsun Moon, K. Moon, S. M. Girvin · 99 citations
Computer Science · Physics and Astronomy · #Charge qubit #Circuit quantum electrodynamics #Cooper pair #Coupling (piping) #Electrical engineering #Microwave #Noise (video) #Optoelectronics #Parametric statistics #Phase qubit #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum electrodynamics #Quantum mechanics #Qubit #Resonator #Superconductivity #Transmission line #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.95.140504
published in Physical Review Letters 95(14), 140504 (American Physical Society) · 4 pages, accepted for publication in Phys. Rev. Lett
arxiv created 2005/09/22 · openalex publication_date 2005/09/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study theoretically the parametric down-conversion and squeezing of microwaves using cavity quantum electrodynamics of a superconducting Cooper-pair box (CPB) qubit located inside a transmission line resonator. The nonlinear susceptibility chi2 describing three-wave mixing can be tuned by dc gate voltage applied to the CPB and vanishes by symmetry at the charge degeneracy point. We show that the coherent coupling of different cavity modes through the qubit can generate a squeezed state. Based on parameters realized in recent successful circuit QED experiments, squeezing of 95% approximately 13 dB below the vacuum noise level should be readily achievable.