Research output: Book/Report/Proceedings › Proceedings
Research output: Book/Report/Proceedings › Proceedings
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TY - BOOK
T1 - Quantum coherent dynamics of two coupled superconducting charge qubits
AU - Pashkin, Yu. A.
AU - Astafiev, O.
AU - Yamamoto, T.
AU - Nakamura, Y.
AU - Averin, D. V.
AU - Tilma, T.
AU - Nori, F.
AU - Tsai, J. S.
PY - 2005
Y1 - 2005
N2 - 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.
AB - 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.
U2 - 10.1117/12.620486
DO - 10.1117/12.620486
M3 - Proceedings
VL - 5833
BT - Quantum coherent dynamics of two coupled superconducting charge qubits
PB - SPIE
T2 - 18TH INTERNATIONAL CONFERENCE ON PHOTOELECTRONICS AND NIGHT VISION DEVICES AND QUANTUM INFORMATICS 2004
Y2 - 10 January 2004 through 10 October 2004
ER -