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Microcavity controlled coupling of excitonic qubits.

Albert F, Sivalertporn K, Kasprzak J, Strauß M, Schneider C, Höfling S, Kamp M, Forchel A, Reitzenstein S, Muljarov EA, Langbein W - Nat Commun (2013)

Bottom Line: This is enabled by two-dimensional spectroscopy of the sample's coherent response, a sensitive probe of the coherent coupling.The results are quantitatively understood in a rigorous description of the cavity-mediated coupling of the quantum dot excitons.This mechanism can be used, for instance in photonic crystal cavity networks, to enable a long-range, non-local coherent coupling.

View Article: PubMed Central - PubMed

Affiliation: Technische Physik, Physikalisches Institut, and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, Würzburg D-97074, Germany.

ABSTRACT
Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. This process is intuitively pictured by a pair of mechanical oscillators, coupled by a spring, allowing for a reversible exchange of excitation. On a microscopic level, the most relevant mechanism of coherent coupling of distant quantum bits--like trapped ions, superconducting qubits or excitons confined in semiconductor quantum dots--is coupling via the electromagnetic field. Here we demonstrate the controlled coherent coupling of spatially separated quantum dots via the photon mode of a solid state microresonator using the strong exciton-photon coupling regime. This is enabled by two-dimensional spectroscopy of the sample's coherent response, a sensitive probe of the coherent coupling. The results are quantitatively understood in a rigorous description of the cavity-mediated coupling of the quantum dot excitons. This mechanism can be used, for instance in photonic crystal cavity networks, to enable a long-range, non-local coherent coupling.

No MeSH data available.


Related in: MedlinePlus

Coherent dynamics measured in four-wave mixing.Delay time dependence of the coherent response for T=19 K (top) and T=13.5 K (bottom). Spectrally resolved FWM power , measured (a,f) and predicted (b,g), on a logarithmic colour scale over four orders of magnitude. Time-resolved FWM power , measured (c,h) and predicted (d,i) over three orders. (e,j) Time-integrated FWM power , measured (black circles) and predicted (red line), and measured  (blue triangles). The noise of  is given as open circles.
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f3: Coherent dynamics measured in four-wave mixing.Delay time dependence of the coherent response for T=19 K (top) and T=13.5 K (bottom). Spectrally resolved FWM power , measured (a,f) and predicted (b,g), on a logarithmic colour scale over four orders of magnitude. Time-resolved FWM power , measured (c,h) and predicted (d,i) over three orders. (e,j) Time-integrated FWM power , measured (black circles) and predicted (red line), and measured (blue triangles). The noise of is given as open circles.

Mentions: The resulting measurements and corresponding predictions of FWM of the system are given in Fig. 3 as function of time delay τ for two different detuning parameters. The FWM power for eV (T=19 K) is shown spectrally resolved in Fig. 3a and time resolved in Fig. 3c. A dynamics significantly richer than in a single exciton case10 is observed, as expected from the larger number of levels in the first and second rungs, providing 32 instead of 6 transitions contributing to the FWM (see Fig. 2). The time-integrated FWM power and the power at a given time tm=21 ps corresponding to the build-up lag of the FWM in such strongly coupled exciton-cavity systems10 are presented in Fig. 3e. On a qualitative level, we notice the FWM beat as a function of τ with a period of about 17 ps, corresponding to a spectral splitting of 243 μeV. This is much larger than the Rabi splitting of any individual exciton, indicating that all four polaritons contribute towards the coherent dynamics. In Fig. 3b we present the predicted FWM corresponding to Fig. 3a, using the exciton and cavity parameters retrieved from the μPL data (see Fig. 1 and Supplementary Note 2). The prediction, which takes into account the coherent evolution in the Tavis-Cummings ladder shown in Fig. 2, reproduces the rich features of the measurements quantitatively.


Microcavity controlled coupling of excitonic qubits.

Albert F, Sivalertporn K, Kasprzak J, Strauß M, Schneider C, Höfling S, Kamp M, Forchel A, Reitzenstein S, Muljarov EA, Langbein W - Nat Commun (2013)

Coherent dynamics measured in four-wave mixing.Delay time dependence of the coherent response for T=19 K (top) and T=13.5 K (bottom). Spectrally resolved FWM power , measured (a,f) and predicted (b,g), on a logarithmic colour scale over four orders of magnitude. Time-resolved FWM power , measured (c,h) and predicted (d,i) over three orders. (e,j) Time-integrated FWM power , measured (black circles) and predicted (red line), and measured  (blue triangles). The noise of  is given as open circles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3644086&req=5

f3: Coherent dynamics measured in four-wave mixing.Delay time dependence of the coherent response for T=19 K (top) and T=13.5 K (bottom). Spectrally resolved FWM power , measured (a,f) and predicted (b,g), on a logarithmic colour scale over four orders of magnitude. Time-resolved FWM power , measured (c,h) and predicted (d,i) over three orders. (e,j) Time-integrated FWM power , measured (black circles) and predicted (red line), and measured (blue triangles). The noise of is given as open circles.
Mentions: The resulting measurements and corresponding predictions of FWM of the system are given in Fig. 3 as function of time delay τ for two different detuning parameters. The FWM power for eV (T=19 K) is shown spectrally resolved in Fig. 3a and time resolved in Fig. 3c. A dynamics significantly richer than in a single exciton case10 is observed, as expected from the larger number of levels in the first and second rungs, providing 32 instead of 6 transitions contributing to the FWM (see Fig. 2). The time-integrated FWM power and the power at a given time tm=21 ps corresponding to the build-up lag of the FWM in such strongly coupled exciton-cavity systems10 are presented in Fig. 3e. On a qualitative level, we notice the FWM beat as a function of τ with a period of about 17 ps, corresponding to a spectral splitting of 243 μeV. This is much larger than the Rabi splitting of any individual exciton, indicating that all four polaritons contribute towards the coherent dynamics. In Fig. 3b we present the predicted FWM corresponding to Fig. 3a, using the exciton and cavity parameters retrieved from the μPL data (see Fig. 1 and Supplementary Note 2). The prediction, which takes into account the coherent evolution in the Tavis-Cummings ladder shown in Fig. 2, reproduces the rich features of the measurements quantitatively.

Bottom Line: This is enabled by two-dimensional spectroscopy of the sample's coherent response, a sensitive probe of the coherent coupling.The results are quantitatively understood in a rigorous description of the cavity-mediated coupling of the quantum dot excitons.This mechanism can be used, for instance in photonic crystal cavity networks, to enable a long-range, non-local coherent coupling.

View Article: PubMed Central - PubMed

Affiliation: Technische Physik, Physikalisches Institut, and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, Würzburg D-97074, Germany.

ABSTRACT
Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. This process is intuitively pictured by a pair of mechanical oscillators, coupled by a spring, allowing for a reversible exchange of excitation. On a microscopic level, the most relevant mechanism of coherent coupling of distant quantum bits--like trapped ions, superconducting qubits or excitons confined in semiconductor quantum dots--is coupling via the electromagnetic field. Here we demonstrate the controlled coherent coupling of spatially separated quantum dots via the photon mode of a solid state microresonator using the strong exciton-photon coupling regime. This is enabled by two-dimensional spectroscopy of the sample's coherent response, a sensitive probe of the coherent coupling. The results are quantitatively understood in a rigorous description of the cavity-mediated coupling of the quantum dot excitons. This mechanism can be used, for instance in photonic crystal cavity networks, to enable a long-range, non-local coherent coupling.

No MeSH data available.


Related in: MedlinePlus