Measurement of the excited-state lifetime of a microelectronic circuit.
We demonstrate that a continuously measured microelectronic circuit, the Cooper-pair box measured by a radio-frequency single-electron transistor, approximates a quantum two-level system. We extract the Hamiltonian of the circuit through resonant spectroscopy and measure the excited-state lifetime. The lifetime is more than 10(5) times longer than the inverse transition frequency of the two-level system, even though the measurement is active. This lifetime is also comparable to an estimate of the known upper limit, set by spontaneous emission, for this circuit.
Lehnert
K W
KW
Department of Applied Physics and Physics, Yale University, New Haven, Connecticut 06511, USA. konrad.lehnert@yale.edu
Bladh
K
K
Spietz
L F
LF
Gunnarsson
D
D
Schuster
D I
DI
Delsing
P
P
Schoelkopf
R J
RJ