Ultrafast quantum nondemolition measurements based on a diamond-shaped artificial atom

作者：Diniz I^*; Dumur E; Buisson O; Auffeves A

来源：Physical Review A, 2013, 87(3): 033837.

DOI：10.1103/PhysRevA.87.033837

We propose a quantum nondemolition (QND) readout scheme for a superconducting artificial atom coupled to a resonator in a circuit QED architecture, for which we estimate a very high measurement fidelity without Purcell effect limitations. The device consists of two transmons coupled by a large inductance, giving rise to a diamond-shaped artificial atom with a logical qubit and an ancilla qubit interacting through a cross-Kerr-like term. The ancilla is strongly coupled to a transmission line resonator. Depending on the qubit state, the ancilla is resonantly or dispersively coupled to the resonator, leading to a large contrast in the transmitted microwave signal amplitude. This original method can be implemented with a state-of-the-art Josephson parametric amplifier, leading to QND measurements in a few tens of nanoseconds with fidelity as large as 99.9%. DOI: 10.1103/PhysRevA.87.033837

• 出版日期2013-3-28