Measurement of the entanglement of two superconducting qubits via state tomography.
Demonstration of quantum entanglement, a key resource in quantum computation arising from a nonclassical correlation of states, requires complete measurement of all states in varying bases. By using simultaneous measurement and state tomography, we demonstrated entanglement between two solid-state qubits. Single qubit operations and capacitive coupling between two super-conducting phase qubits were used to generate a Bell-type state. Full two-qubit tomography yielded a density matrix showing an entangled state with fidelity up to 87%. Our results demonstrate a high degree of unitary control of the system, indicating that larger implementations are within reach.
Steffen
Matthias
M
Department of Physics and California Nano Systems Institute, University of California, Santa Barbara, CA 93106, USA.
Ansmann
M
M
Bialczak
Radoslaw C
RC
Katz
N
N
Lucero
Erik
E
McDermott
R
R
Neeley
Matthew
M
Weig
E M
EM
Cleland
A N
AN
Martinis
John M
JM