Quantum Networking II and Quantum Memories

Transduction of the state of a matter qubit to a flying qubit coupled with an architecture agnostic interconnect would allow the application of photon-based entanglement generation protocols to be used to realize hybrid quantum systems. Indistinguishability of photons produced by each node determines fidelity for these protocols. Control of the temporal waveform of the photons produced by emitters of different lifetimes is therefore a crucial step towards the realization of mixed architecture networks. We present a novel technique to produce photons of any temporal profile from any architecture with access to a state that undergoes radiative decay with the only requirements being control of the phase-parity and amplitude of a single driving field. 

Previous approaches to generating indistinguishable photons have made use of post-emission tools such as gating photon time of arrival or circuit based pulse shaping, which suffer from low efficiency as the difference in lifetime between emitters grows. Alternatively, cavity-based Stimulated Raman Adiabatic Passage experiments modulate fields to control photon shape during emission but are limited by the adiabatic condition, require specialized optics and are coupled to the cavity mode. The technique presented here avoids these constraints and represents a complementary tool for quantum networking. 

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We implement this experiment in a trapped ion system, and describe laser pulse optimization and measurement of photon temporal waveforms. We estimate a process fidelity >0.996. This work opens new avenues for hybrid quantum systems with additional applications for same-qubit type protocols such as selecting waveforms which are insensitive to interferometric instability. 

Funding acknowledgement

This research is supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, under Award No. DESC0020378