Entangled systems display correlations that are stronger than can be obtained classically. This makes entanglement an essential resource for a number of applications, such as quantum information processing, quantum computing and quantum communications1,2. The ability to control the transfer of entanglement between different locations will play a key role in these quantum protocols and enable quantum networks3. Such a transfer requires a system that can delay quantum correlations without significant degradation, effectively acting as a short-term quantum memory. An important benchmark for such systems is the ability to delay Einstein–Podolsky–Rosen (EPR) levels of entanglement and to be able to tune the delay. EPR entanglement is the basis for a number of quantum protocols, allowing the remote inference of the properties of one system (to better than its standard quantum limit) through measurements on the other correlated system. Here we show that a four-wave mixing process based on a double-lambda scheme in hot 85Rb vapour allows us to obtain an optically tunable delay for EPR entangled beams of light. A significant maximum delay, of the order of the width of the cross-correlation function, is achieved. The four-wave mixing also preserves the quantum spatial correlations of the entangled beams. We take advantage of this property to delay entangled images, making this the first step towards a quantum memory for images4.
This is a preview of subscription content, access via your institution
Open Access articles citing this article.
Scientific Reports Open Access 13 January 2022
Light: Science & Applications Open Access 12 May 2021
Nature Communications Open Access 03 August 2020
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Galindo, A. & Martin-Delgado, M. A. Information and computation: Classical and quantum aspects. Rev. Mod. Phys. 74, 347–423 (2002)
Braunstein, S. L. & van Loock, P. Quantum information with continuous variables. Rev. Mod. Phys. 77, 513–577 (2005)
Kimble, H. J. The quantum internet. Nature 453, 1023–1030 (2008)
Vasilyev, D. V., Sokolov, I. V. & Polzik, E. S. Quantum memory for images: A quantum hologram. Phys. Rev. A 77, 020302(R) (2008)
Hau, L. V., Harris, S. E., Dutton, Z. & Behroozi, C. H. Light speed reduction to 17 metres per second in an ultracold atomic gas. Nature 397, 594–598 (1999)
Camacho, R. M., Pack, M. V., Howell, J. C., Schweinsberg, A. & Boyd, R. W. Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor. Phys. Rev. Lett. 98, 153601 (2007)
Boyer, V., McCormick, C. F., Arimondo, E. & Lett, P. D. Ultraslow propagation of matched pulses by four-wave mixing in an atomic vapor. Phys. Rev. Lett. 99, 143601 (2007)
Broadbent, C. J., Camacho, R. M., Xin, R. & Howell, J. C. Preservation of energy-time entanglement in a slow light medium. Phys. Rev. Lett. 100, 133602 (2008)
Chaneliere, T. et al. Storage and retrieval of single photons transmitted between remote quantum memories. Nature 438, 833–836 (2005)
Eisaman, M. D. et al. Electromagnetically induced transparency with tunable single-photon pulses. Nature 438, 837–841 (2005)
Choi, K. S., Deng, H., Laurat, J. & Kimble, H. J. Mapping photonic entanglement into and out of a quantum memory. Nature 452, 67–71 (2008)
Akamatsu, D. et al. Ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. Phys. Rev. Lett. 99, 153602 (2007)
Honda, K. et al. Storage and retrieval of a squeezed vacuum. Phys. Rev. Lett. 100, 093601 (2008)
Appel, J., Figueroa, E., Korystov, D., Lobino, M. & Lvovsky, A. I. Quantum memory for squeezed light. Phys. Rev. Lett. 100, 093602 (2008)
Hétet, G. et al. Delay of squeezing and entanglement using electromagnetically induced transparency in a vapour cell. Opt. Express 16, 7369–7381 (2008)
Duan, L. M., Giedke, G., Cirac, J. I. & Zoller, P. Inseparability criterion for continuous variable systems. Phys. Rev. Lett. 84, 2722–2725 (2000)
Reid, M. D. Demonstration of the Einstein-Podolsky-Rosen paradox using nondegenerate parametric amplification. Phys. Rev. A 40, 913–923 (1989)
McCormick, C. F., Marino, A. M., Boyer, V. & Lett, P. D. Strong low-frequency quantum correlations from a four-wave-mixing amplifier. Phys. Rev. A 78, 043816 (2008)
Boyer, V., Marino, A. M., Pooser, R. C. & Lett, P. D. Entangled images from four-wave mixing. Science 321, 544–547 (2008)
Ou, Z. Y., Pereira, S. F., Kimble, H. J. & Peng, K. C. Realization of the Einstein-Podolsky-Rosen paradox for continuous-variables. Phys. Rev. Lett. 68, 3663–3666 (1992)
Bowen, W. P., Schnabel, R., Lam, P. K. & Ralph, T. C. Experimental characterization of continuous-variable entanglement. Phys. Rev. A 69, 012304 (2004)
Weedbrook, C., Grosse, N. B., Symul, T., Lam, P. K. & Ralph, T. C. Quantum cloning of continuous-variable entangled states. Phys. Rev. A 77, 052313 (2008)
Tan, S. M. Confirming entanglement in continuous variable quantum teleportation. Phys. Rev. A 60, 2752–2758 (1999)
Grosshans, F. & Grangier, P. Quantum cloning and teleportation criteria for continuous quantum variables. Phys. Rev. A 64, 010301(R) (2001)
Boyd, R. W., Gauthier, D. J., Gaeta, A. L. & Willner, A. E. Maximum time delay achievable on propagation through a slow-light medium. Phys. Rev. A 71, 023801 (2005)
Vudyasetu, P. K., Camacho, R. M. & Howell, J. C. Storage and retrieval of multimode transverse images in hot atomic rubidium vapor. Phys. Rev. Lett. 100, 123903 (2008)
Shuker, M., Firstenberg, O., Pugatch, R., Ron, A. & Davidson, N. Storing images in warm atomic vapor. Phys. Rev. Lett. 100, 223601 (2008)
Boyer, V., Marino, A. M. & Lett, P. D. Generation of spatially broadband twin beams for quantum imaging. Phys. Rev. Lett. 100, 143601 (2008)
Collins, O. A., Jenkins, S. D., Kuzmich, A. & Kennedy, T. A. B. Multiplexed memory insensitive quantum repeaters. Phys. Rev. Lett. 98, 060502 (2007)
Tordrup, K., Negretti, A. & Molmer, K. Holographic quantum computing. Phys. Rev. Lett. 101, 040501 (2008)
R.C.P. is supported by the Intelligence Community Postdoctoral Program.
About this article
Cite this article
Marino, A., Pooser, R., Boyer, V. et al. Tunable delay of Einstein–Podolsky–Rosen entanglement. Nature 457, 859–862 (2009). https://doi.org/10.1038/nature07751
This article is cited by
Scientific Reports (2022)
Generation of enhanced entanglement of directly and indirectly coupled modes in a two-cavity magnomechanical system
Quantum Information Processing (2022)
Light: Science & Applications (2021)
Nature Communications (2020)
Atomic dispensers for thermoplasmonic control of alkali vapor pressure in quantum optical applications
Nature Communications (2019)