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Stochastic-master-equation analysis of optimized three-qubit nondemolition parity measurements

Lars Tornberg (Institutionen för mikroteknologi och nanovetenskap, Tillämpad kvantfysik) ; S. Barzanjeh ; D. P. DiVincenzo
Physical Review A. Atomic, Molecular, and Optical Physics (1050-2947). Vol. 89 (2014), 3, p. 11.
[Artikel, refereegranskad vetenskaplig]

We analyzea direct parity measurement of the state of three superconducting qubits in circuit quantum electrodynamics. The parity is inferred from a homodyne measurement of the reflected and transmitted microwave radiation, and the measurement is direct in the sense that the parity is measured without the need for any quantum circuit operations or for ancilla qubits. Qubits are coupled to two resonant-cavity modes, allowing the steady state of the emitted radiation to satisfy the necessary conditions to act as a pointer state for the parity. However, the transient dynamics violates these conditions, and we analyze this detrimental effect and show that it can be overcome in the limit of a weak measurement signal. Our analysis shows that, with a moderate degree of postselection, it is possible to achieve postmeasurement states with fidelity of order 95%. We believe that this type of measurement could serve as a benchmark for future error correction protocols in a scalable architecture.



Denna post skapades 2014-05-21. Senast ändrad 2015-01-21.
CPL Pubid: 198394

 

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Institutioner (Chalmers)

Institutionen för mikroteknologi och nanovetenskap, Tillämpad kvantfysik

Ämnesområden

Fysik

Chalmers infrastruktur