We realize entanglement-by-measurement of two superconducting transmon qubits on separate 2D circuit QED chips. Two qubit-resonator pairs are tuned such that a microwave driving field bouncing successively from the two resonators does not distinguish the two odd-parity states of the qubits [1]. Thus, a half-parity measurement is realized, projecting the qubits onto the $\vert 00 \rangle$ state, the $\vert 11 \rangle$ state or the odd subspace. We use it to project an initial superposition state to a Bell state. The entanglement-by-measurement dynamics are verified via quantum state tomography. Conditioning the post-measurement state on the odd-subspace measurement outcome shows clear signatures of entanglement. Engineering the time-dependent resonator driving fields can reduce the distinguishability within the odd subspace, improving the entanglement. This scheme enables linking up 2D circuit QED processors in a quantum network. [1] N. Roche et al., Phys. Rev. Lett. 112, 170501 (2014)
*Research funded by the Netherlands Organisation for Scientific Research (NWO), the Dutch Foundation for Fundamental Research on Matter (FOM), and the ERC Synergy grant QC-lab.
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Authors
Christian Dickel
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
Sarwan Peiter
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
Ramiro Sagastizabal
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
Nathan Langford
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
Ben Criger
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
David Thoen
Department of Microelectronics and Kavli Institute of Nanoscience, Delft University of Technology
Akira Endo
Department of Microelectronics and Kavli Institute of Nanoscience, Delft University of Technology
Alessandro Bruno
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
Leonardo DiCarlo
QuTech and Kavli Institute of Nanoscience, TU Delft, The Netherlands
QuTech and Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands
QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
QuTech and Kavli Institute of Nanoscience, Delft University of Technology and Intel Corporation
QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
QuTech and Kavli Institute of Nanoscience, Delft University of Technology
