Abstract
Deterministic optical quantum logic requires a nonlinear quantum process that alters the phase of a quantum optical state by π through interaction with only one photon. Here, we demonstrate a large conditional cross-phase modulation between a signal field, stored inside an atomic quantum memory, and a control photon that traverses a high-finesse optical cavity containing the atomic memory. This approach avoids fundamental limitations associated with multimode effects for traveling optical photons. We measure a conditional cross-phase shift of π=6 (and up to π=3 by postselection on photons that remain in the system longer than average) between the retrieved signal and control photons, and confirm deterministic entanglement between the signal and control modes by extracting a positive concurrence. By upgrading to a state-of-the-art cavity, our system can reach a coherent phase shift of π at low loss, enabling deterministic and universal photonic quantum logic.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9740-9744 |
| Number of pages | 5 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 113 |
| Issue number | 35 |
| DOIs | |
| State | Published - Aug 30 2016 |
Funding
We thank M. Lukin and J. Thompson for enlightening discussions. This work was supported by the National Science Foundation (NSF), and Multidisciplinary University Research Initiative grants through Air Force Office of Scientific Research and Army Research Office. K.M.B. acknowledges support from NSF Integrative Graduate Education and Research Traineeship under Grant 0801525.
Keywords
- Cavity quantum electrodynamics
- Cross-phase modulation
- Electromagnetically induced transparency
- Photonic quantum gate
- Single-photon kerr nonlinearity
ASJC Scopus subject areas
- General