Two-qubit state tomography using a joint dispersive readout.
Quantum state tomography is an important tool in quantum information science for complete characterization of multiqubit states and their correlations. Here we report a method to perform a joint simultaneous readout of two superconducting qubits dispersively coupled to the same mode of a microwave transmission line resonator. The nonlinear dependence of the resonator transmission on the qubit state dependent cavity frequency allows us to extract the full two-qubit correlations without the need for single-shot readout of individual qubits. We employ standard tomographic techniques to reconstruct the density matrix of two-qubit quantum states.
Filipp
S
S
Department of Physics, ETH Zurich, CH-8093 Zurich, Switzerland. filipp@phys.ethz.ch
Maurer
P
P
Leek
P J
PJ
Baur
M
M
Bianchetti
R
R
Fink
J M
JM
Göppl
M
M
Steffen
L
L
Gambetta
J M
JM
Blais
A
A
Wallraff
A
A