Profile
Outputs
| Title | Category | Date | Authors |
| Remote Preparation of a Single-Mode Photonic Qubit by Measuring Field Quadrature Noise University of Calgary, Universitat Konstanz | Publication | 2004-01-01 | S. Babichev, B. Brezger, A. Lvovsky | | Continuous-variable experiments with a nonlocal single photon A two-mode optical qubit is generated when a single photon from a parametric down conversion source entangles itself with a vacuum on a beam splitter. We have characterized this dual-rail state by means of homodyne tomography. From the quadrature statistics, applying the maximum likelihood method, density matrix is calculated which extends over the entire Hilbert space and thus reveals, for the first time, complete information about the qubit as a state of the electromagnetic field. A nonlocal nature of the reconstructed state is shown by a violation of the Bell inequality for the experimental data converted to a dichotomic format. This experiment can be interpreted as remote preparation of an arbitrary single-mode optical qubit. By measuring a quadrature on one of the spatial modes of the entangled state, we project the other mode onto a coherent superposition of the single-photon and vacuum states. Surprisingly, the state obtained in this manner can be of higher purity than the single-photon resource we started with.
University of Calgary | Presentation | 2004-07-20 | S. Babichev, J. Appel, A. Lvovsky | | Continuous-variable experiments with optical qubits University of Calgary | Publication | 2005-01-01 | A. Lvovsky, S. Babichev, J. Appel | | Continuous-variable experiments with optical qubits University of Calgary | Presentation | 2004-11-11 | A. Lvovsky, S. Babichev, J. Appel | | Universal homodyne detector with high bandwidthWir stellen einen Homodyne-Detektor mit einer Bandbreite >
200 MHz vor. Ein Ti:Sa Laser (Coherent Mira, 76 MHz Pulswiederholrate)
dient als Lokaloszillator in einem balancierten Detektionsschema. Die
Pulse werden mittels zweier vorgespannter Si-PIN Fotodioden detektiert,
deren Differenzstrom in einem als Transimpedanzwandler geschalteten
Operationsverst¨arker verst¨arkt wird. Bei einer Leistung von 10 mW des
Lokaloszillators liegt das optische Schrotrauschen bis zu 15 dB ¨uber dem
elektronischen Rauschen des Detektors. Die hohe Bandbreite des Detektors
erlaubt Messungen sowohl im Frequenz- als auch im Zeitraum bei
der vollen Pulswiederholrate des Lokaloszillators, z.B. f¨ur Quantenkommunikation
mit kontinuierlichen Variablen. University of Calgary | Presentation | 2006-03-13 | F. Vewinger, S. Babichev, J. Appel, A. Lvovsky | | Instant single-photon Fock state tomography University of Calgary | Publication | 2009-01-01 | S. R. Huisman, N. Jain, S. Babichev, F. Vewinger, A. -. Zhang, S. -. Youn, A. Lvovsky |
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