Share Email Print
cover

Proceedings Paper

Quantum coherent dynamics of two coupled superconducting charge qubits
Author(s): Yu. A. Pashkin; O. Astafiev; T. Yamamoto; Y. Nakamura; D. V. Averin; T. Tilma; F. Nori; J. S. Tsai
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

We have analyzed and measured the quantum coherent dynamics of a circuit containing two coupled superconducting charge qubits. Each qubit is based on a Cooper pair box connected to a reservoir electrode through a Josephson junction. Two qubits are coupled electrostatically by a small island overlapping both Cooper pair boxes. Quantum state manipulation ofthe qubit circuit is done by applying non-adiabatic voltage pulses to the common gate. We read out each qubit by means of probe electrodes connected to Cooper pair boxes through high-Ohmic tunnel junctions. With such a setup the measured pulse-induced probe currents are proportional to the probability for each qubit to have an extra Cooper pai1r after the manipulation. As expected from theory and observed experimentally the measured pulse-induced current in each probe has two frequency components whose position on the frequency axis can be externally controlled. This is a result ofthe inter-qubit coupling which is also responsible for the avoided level crossing that we observed in the qubits' spectra. Our simulations show that in the absence of decoherence and with a rectangular pulse shape the system remains entangled most ofthe time reaching maximally entangled states at certain instances.

Paper Details

Date Published: 1 June 2005
PDF: 11 pages
Proc. SPIE 5833, Quantum Informatics 2004, (1 June 2005); doi: 10.1117/12.620486
Show Author Affiliations
Yu. A. Pashkin, RIKEN-The Institute of Physical and Chemical Research (Japan)
O. Astafiev, RIKEN-The Institute of Physical and Chemical Research (Japan)
T. Yamamoto, RIKEN-The Institute of Physical and Chemical Research (Japan)
NEC Fundamental Research Labs. (Japan)
Y. Nakamura, RIKEN-The Institute of Physical and Chemical Research (Japan)
NEC Fundamental Research Labs. (Japan)
D. V. Averin, Stony Brook Univ./SUNY (United States)
T. Tilma, RIKEN-The Institute of Physical and Chemical Research (Japan)
Univ. of Michigan/Ann Arbor (United States)
F. Nori, RIKEN-The Institute of Physical and Chemical Research (Japan)
Univ. of Michigan/Ann Arbor (United States)
J. S. Tsai, RIKEN-The Institute of Physical and Chemical Research (Japan)
NEC Fundamental Research Labs. (Japan)


Published in SPIE Proceedings Vol. 5833:
Quantum Informatics 2004
Yuri I. Ozhigov, Editor(s)

© SPIE. Terms of Use
Back to Top