تقرير
Deterministic entanglement of superconducting qubits by parity measurement and feedback
| العنوان: | Deterministic entanglement of superconducting qubits by parity measurement and feedback |
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| المؤلفون: | Ristè, D., Dukalski, M., Watson, C. A., de Lange, G., Tiggelman, M. J., Blanter, Ya. M., Lehnert, K. W., Schouten, R. N., DiCarlo, L. |
| المصدر: | Nature 502, 350-354 (2013) |
| سنة النشر: | 2013 |
| المجموعة: | Condensed Matter Quantum Physics |
| مصطلحات موضوعية: | Condensed Matter - Mesoscale and Nanoscale Physics, Quantum Physics |
| الوصف: | The stochastic evolution of quantum systems during measurement is arguably the most enigmatic feature of quantum mechanics. Measuring a quantum system typically steers it towards a classical state, destroying any initial quantum superposition and any entanglement with other quantum systems. Remarkably, the measurement of a shared property between non-interacting quantum systems can generate entanglement starting from an uncorrelated state. Of special interest in quantum computing is the parity measurement, which projects a register of quantum bits (qubits) to a state with an even or odd total number of excitations. Crucially, a parity meter must discern the two parities with high fidelity while preserving coherence between same-parity states. Despite numerous proposals for atomic, semiconducting, and superconducting qubits, realizing a parity meter creating entanglement for both even and odd measurement results has remained an outstanding challenge. We realize a time-resolved, continuous parity measurement of two superconducting qubits using the cavity in a 3D circuit quantum electrodynamics (cQED) architecture and phase-sensitive parametric amplification. Using postselection, we produce entanglement by parity measurement reaching 77% concurrence. Incorporating the parity meter in a feedback-control loop, we transform the entanglement generation from probabilistic to fully deterministic, achieving 66% fidelity to a target Bell state on demand. These realizations of a parity meter and a feedback-enabled deterministic measurement protocol provide key ingredients for active quantum error correction in the solid state. Comment: 7 pages, 4 figures, and 9 supplementary figures |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1038/nature12513 |
| URL الوصول: | http://arxiv.org/abs/1306.4002 |
| رقم الأكسشن: | edsarx.1306.4002 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1038/nature12513 |
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