Josephson-Junction Qubits and the Readout Process by Single-Electron Transistors
| dc.creator | Makhlin, Yuriy | |
| dc.creator | Schoen, Gerd | |
| dc.creator | Shnirman, Alexander | |
| dc.date | 1998-11-03 | |
| dc.date | 1999-12-02 | |
| dc.date.accessioned | 2026-07-07T03:11:52Z | |
| dc.date.available | 2026-07-07T03:11:52Z | |
| dc.description | Several physical realizations of quantum bits have been proposed. Of those, nano-electronic devices appear most suitable for large-scale integration and potential applications. We suggest to use low-capacitance Josephson junctions, exploiting the coherence of tunneling in the superconducting state combined with the possibility to control individual charges by Coulomb blockade effects (cond-mat/9706016,cond-mat/9808067). These systems constitute quantum bits, with logical states differing by one Cooper-pair charge. Single- and two-bit operations can be performed by applying a sequence of gate voltages. The phase coherence time is sufficiently long to allow a series of these steps. In addition to the manipulation of qubits the resulting quantum state has to be read out. This can be accomplished by coupling a single-electron transistor capacitively to the qubit (cond-mat/9801125). To describe this quantum measurement process we study the time evolution of the density matrix of the coupled system. Only when a transport voltage is turned on, the transistor destroys the phase coherence of the qubit; in this case within a short time. The measurement is accomplished after a longer time scale, when the signal resolves the different quantum states. At still longer times the measurement process itself destroys the information about the initial state. We present a suitable set of system parameters, which can be realized by present-day technology. | |
| dc.description | RevTex, 19 pages, 9 figures; contribution to "Exploring the Quantum-Classical Frontier: Recent Advances in Macroscopic and Mesoscopic Quantum Phenomena." Eds. J.R.Friedman and S.Han Presentation improved | |
| dc.identifier | https://arxiv.org/abs/cond-mat/9811029 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/9811029 | |
| dc.identifier | In: Exploring the Quantum-Classical Frontier, pp. 405-440. Eds. J.R. Friedman and S. Han, Nova Science, Commack, NY, 2002 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/28741 | |
| dc.subject | Mesoscale and Nanoscale Physics | |
| dc.subject | Quantum Physics | |
| dc.title | Josephson-Junction Qubits and the Readout Process by Single-Electron Transistors | |
| dc.type | text |