2006/04/04 by J. Leppäkangas, Juha Leppäkangas, E. Thuneberg +5
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.74.054504
published as Phys. Rev. B 74 054504 (2006) · 9 pages, 9 figures, Revtex4
arxiv created 2006/04/04 · openalex publication_date 2006/08/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We analyze tunneling of Cooper pairs across voltage biased asymmetric single-Cooper-pair transistors. Also tunneling of Cooper pairs across two capacitively coupled Cooper-pair boxes is considered, when the capacitive coupling and Cooper pair tunneling are provided by a small Josephson junction between the islands. The theoretical analysis is done at subgap voltages, where the current-voltage characteristics depend strongly on the macroscopic eigenstates of the island(s) and their coupling to the dissipative environment. As the environment we use an impedance which satisfies Re[Z(\ensuremathω)]⪡RQ and a few LC oscillators in series with Z(\ensuremathω). The numerically calculated I\text\ensuremath-V curves are compared with experiments where the quantum states of mesoscopic SQUIDs are probed with inelastic Cooper pair tunneling. The main features of the observed I\text\ensuremath-V data are reproduced. Especially, we find traces of band structure in the higher excited states of the Cooper-pair boxes as well as traces of multiphoton processes between two Cooper-pair boxes in the regime of large Josephson coupling EJ⪢EC.