Decoherence dynamics of complex photon states in a superconducting circuit.
Quantum states inevitably decay with time into a probabilistic mixture of classical states due to their interaction with the environment and measurement instrumentation. We present the first measurement of the decoherence dynamics of complex photon states in a condensed-matter system. By controllably preparing a number of distinct quantum-superposed photon states in a superconducting microwave resonator, we show that the subsequent decay dynamics can be quantitatively described by taking into account only two distinct decay channels: energy relaxation and pure dephasing. Our ability to prepare specific initial quantum states allows us to measure the evolution of specific elements in the quantum density matrix in a very detailed manner that can be compared with theory.
Wang
H
H
Department of Physics, University of California, Santa Barbara, California 93106, USA.
Hofheinz
M
M
Ansmann
M
M
Bialczak
R C
RC
Lucero
Erik
E
Neeley
M
M
O'Connell
A D
AD
Sank
D
D
Weides
M
M
Wenner
J
J
Cleland
A N
AN
Martinis
John M
JM