2015/02/13 by H. S. Ku, William Kindel, W. F. Kindel +8
Computer Science · Physics and Astronomy · #Beam splitter #Entanglement witness #Laser #Microwave #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #W state #quant-ph
paper · pdf · doi:10.1103/physreva.91.042305
arxiv created 2015/02/13 · openalex publication_date 2015/04/08 · arxiv updated 2015/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
By combining a squeezed propagating microwave field and an unsqueezed vacuum field on a hybrid (microwave beam splitter), we generate entanglement between the two output modes. We verify that we have generated entangled states by making independent and efficient single-quadrature measurements of the two output modes. We observe the entanglement witness EW=\ensuremath-0.263_\ensuremath-0.036+0.001 and the negativity N=0.0824_\ensuremath-0.0004+0.01 with measurement efficiencies at least 26\ifmmode±\else\textpm\fi0.1% and 41\ifmmode±\else\textpm\fi0.2% for channels 1 and 2, respectively. These measurements show that the output two-mode state violates the separability criterion and therefore demonstrates entanglement. This shared entanglement between propagating microwaves provides an important resource for building quantum networks with superconducting microwave systems.