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Quantum memory with strong and controllable Rydberg-level interactions

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ABSTRACT

Realization of distributed quantum systems requires fast generation and long-term storage of quantum states. Ground atomic states enable memories with storage times in the range of a minute, however their relatively weak interactions do not allow fast creation of non-classical collective states. Rydberg atomic systems feature fast preparation of singly excited collective states and their efficient mapping into light, but storage times in these approaches have not yet exceeded a few microseconds. Here we demonstrate a system that combines fast quantum state generation and long-term storage. An initially prepared coherent state of an atomic memory is transformed into a non-classical collective atomic state by Rydberg-level interactions in less than a microsecond. By sheltering the quantum state in the ground atomic levels, the storage time is increased by almost two orders of magnitude. This advance opens a door to a number of quantum protocols for scalable generation and distribution of entanglement.

No MeSH data available.


Single-photon excitation to Rydberg p state.(a) Single-photon spectroscopy of /b>←/r>=/62p3/2, mJ=−3/2> transition. The normalized photoelectric detection rate Sn of the retrieved field is shown as a function of detuning (δr). The data are fit with a Lorentzian profile. (b) N, the population of prepared single excitation (with Ω1 and Ω2 fields ) is shown as a function of Raman excitation population NR. Error bars, ±1 s.d.
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f2: Single-photon excitation to Rydberg p state.(a) Single-photon spectroscopy of /b>←/r>=/62p3/2, mJ=−3/2> transition. The normalized photoelectric detection rate Sn of the retrieved field is shown as a function of detuning (δr). The data are fit with a Lorentzian profile. (b) N, the population of prepared single excitation (with Ω1 and Ω2 fields ) is shown as a function of Raman excitation population NR. Error bars, ±1 s.d.

Mentions: Single-photon excitation from the ground state /b> to the Rydberg state /r> (62p3/2) is studied in Fig. 2. The normalized sum Sn of the D1 and D2 detection rates is shown in Fig. 2a as a function of single-photon detuning δr from the /b>←/r> resonance. The measured (fwhm) width of the spectrum γ/2π=1.3 MHz is largely determined by the 0.7 μs duration of the excitation pulse Ω1. The population of single excitation prepared in /b>, N (at δr=0) is shown in Fig. 2b as a function of Raman excitation population NR in /b> (no coupling to the Rydberg state). N and NR are obtained by normalizing the corresponding probabilities of photoelectric detection by the retrieval, transmission and detection efficiencies (Supplementary Note 3). The data are fit with a function of N=ζχNR exp(−χNR), where ζ=0.20(1) and χ=0.87(4) are adjustable parameters. The fit is suggested by the dephasing mechanism of multi-particle Rydberg excitations put forward in ref. 25. Here ζ corresponds to the population transfer efficiency of the /b>→/r>→/b> process in the absence of loss due to multi-particle dephasing, whereas the maximum single excitation preparation efficiency (including multi-particle dephasing loss) in state /b> is ξm=ζ/e.


Quantum memory with strong and controllable Rydberg-level interactions
Single-photon excitation to Rydberg p state.(a) Single-photon spectroscopy of /b>←/r>=/62p3/2, mJ=−3/2> transition. The normalized photoelectric detection rate Sn of the retrieved field is shown as a function of detuning (δr). The data are fit with a Lorentzian profile. (b) N, the population of prepared single excitation (with Ω1 and Ω2 fields ) is shown as a function of Raman excitation population NR. Error bars, ±1 s.d.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121357&req=5

f2: Single-photon excitation to Rydberg p state.(a) Single-photon spectroscopy of /b>←/r>=/62p3/2, mJ=−3/2> transition. The normalized photoelectric detection rate Sn of the retrieved field is shown as a function of detuning (δr). The data are fit with a Lorentzian profile. (b) N, the population of prepared single excitation (with Ω1 and Ω2 fields ) is shown as a function of Raman excitation population NR. Error bars, ±1 s.d.
Mentions: Single-photon excitation from the ground state /b> to the Rydberg state /r> (62p3/2) is studied in Fig. 2. The normalized sum Sn of the D1 and D2 detection rates is shown in Fig. 2a as a function of single-photon detuning δr from the /b>←/r> resonance. The measured (fwhm) width of the spectrum γ/2π=1.3 MHz is largely determined by the 0.7 μs duration of the excitation pulse Ω1. The population of single excitation prepared in /b>, N (at δr=0) is shown in Fig. 2b as a function of Raman excitation population NR in /b> (no coupling to the Rydberg state). N and NR are obtained by normalizing the corresponding probabilities of photoelectric detection by the retrieval, transmission and detection efficiencies (Supplementary Note 3). The data are fit with a function of N=ζχNR exp(−χNR), where ζ=0.20(1) and χ=0.87(4) are adjustable parameters. The fit is suggested by the dephasing mechanism of multi-particle Rydberg excitations put forward in ref. 25. Here ζ corresponds to the population transfer efficiency of the /b>→/r>→/b> process in the absence of loss due to multi-particle dephasing, whereas the maximum single excitation preparation efficiency (including multi-particle dephasing loss) in state /b> is ξm=ζ/e.

View Article: PubMed Central - PubMed

ABSTRACT

Realization of distributed quantum systems requires fast generation and long-term storage of quantum states. Ground atomic states enable memories with storage times in the range of a minute, however their relatively weak interactions do not allow fast creation of non-classical collective states. Rydberg atomic systems feature fast preparation of singly excited collective states and their efficient mapping into light, but storage times in these approaches have not yet exceeded a few microseconds. Here we demonstrate a system that combines fast quantum state generation and long-term storage. An initially prepared coherent state of an atomic memory is transformed into a non-classical collective atomic state by Rydberg-level interactions in less than a microsecond. By sheltering the quantum state in the ground atomic levels, the storage time is increased by almost two orders of magnitude. This advance opens a door to a number of quantum protocols for scalable generation and distribution of entanglement.

No MeSH data available.