11,476 research outputs found
Magnon dark modes and gradient memory
Extensive efforts have been expended in developing hybrid quantum systems to
overcome the short coherence time of superconducting circuits by introducing
the naturally long-lived spin degree of freedom. Among all the possible
materials, single-crystal yttrium iron garnet has shown up very recently as a
promising candidate for hybrid systems, and various highly coherent
interactions, including strong and even ultra-strong coupling, have been
demonstrated. One distinct advantage of these systems is that the spins are in
the form of well-defined magnon modes, which allows flexible and precise
tuning. Here we demonstrate that by dissipation engineering, a non-Markovian
interaction dynamics between the magnon and the microwave cavity photon can be
achieved. Such a process enables us to build a magnon gradient memory to store
information in the magnon dark modes, which decouple from the microwave cavity
and thus preserve a long life-time. Our findings provide a promising approach
for developing long-lifetime, multimode quantum memories.Comment: 18 pages, 12 figure
Multi-pulse addressing of a Raman quantum memory: configurable beam splitting and efficient readout
Quantum memories are vital to the scalability of photonic quantum information
processing (PQIP), since the storage of photons enables repeat-until-success
strategies. On the other hand the key element of all PQIP architectures is the
beam splitter, which allows to coherently couple optical modes. Here we show
how to combine these crucial functionalities by addressing a Raman quantum
memory with multiple control pulses. The result is a coherent optical storage
device with an extremely large time-bandwidth product, that functions as an
array of dynamically configurable beam splitters, and that can be read out with
arbitrarily high efficiency. Networks of such devices would allow fully
scalable PQIP, with applications in quantum computation, long-distance quantum
communications and quantum metrology.Comment: 4 pages, 3 figure
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