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DESCRIPTION:Near-unity entanglement from an indium-rich nanowire quantum dot source compatible with efficient quantum key distribution\n\nThus far\, the workhorse platform for generating entangled photons for many quantum information experiments has been spontaneous parametric down conversion (SPDC). However\, due to their Poissonian photon statistics\, these sources cannot operate in the high efficiency limit without a significant reduction in the degree of entanglement. In contrast\, there are no such limits placed on semiconductor quantum dots (QDs) embedded in photonic nanostructures. To date\, near-unity entanglement fidelity has not yet been measured from indium-rich QDs\, which are promising candidates for realizing such as source. We performed quantum state tomography using single-photon detectors with ultra-low timing jitter and employ two-photon resonant excitation. We measure a raw peak concurrence and fidelity of 95.3 +/- 0.5% and 97.5 +/- 0.8%\, respectively\, as well as lifetime-weighted average concurrence and fidelity of 0.90 +/- 0.04% and 0.94 +/- 0.04%\, respectively. These results conclusively demonstrate that most of the degradation from unity-measured entanglement fidelity in earlier studies was not due to spin dephasing. Additionally\, we show that the exciton fine structure splitting\, contrary to common understanding\, is not in principle a fundamental barrier to implementing QKD with semiconductor QD entangled photon sources.
X-ALT-DESC;FMTTYPE=text/html:<strong>Near-unity entanglement from an indium-rich nanowire quantum dot source compatible with efficient quantum key distribution</strong><br><br>Thus far, the workhorse platform for generating entangled photons for many quantum information experiments has been spontaneous parametric down conversion (SPDC). However, due to their Poissonian photon statistics, these sources cannot operate in the high efficiency limit without a significant reduction in the degree of entanglement. In contrast, there are no such limits placed on semiconductor quantum dots (QDs) embedded in photonic nanostructures. To date, near-unity entanglement fidelity has not yet been measured from indium-rich QDs, which are promising candidates for realizing such as source. We performed quantum state tomography using single-photon detectors with ultra-low timing jitter and employ two-photon resonant excitation. We measure a raw peak concurrence and fidelity of 95.3 +/- 0.5% and 97.5 +/- 0.8%, respectively, as well as lifetime-weighted average concurrence and fidelity of 0.90 +/- 0.04% and 0.94 +/- 0.04%, respectively. These results conclusively demonstrate that most of the degradation from unity-measured entanglement fidelity in earlier studies was not due to spin dephasing. Additionally, we show that the exciton fine structure splitting, contrary to common understanding, is not in principle a fundamental barrier to implementing QKD with semiconductor QD entangled photon sources.
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SUMMARY:IQC Student Seminar featuring Matteo Pennacchietti
DTSTART;TZID=America/New_York:20230614T120000
DTEND;TZID=America/New_York:20230614T130000
DTSTAMP:20260421T220808Z
TRANSP:OPAQUE
STATUS:CONFIRMED
SEQUENCE:0
LOCATION:QNC 1201
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