In the next decade, quantum technologies will provide revolutionary advances in communications, sensing and metrology, information processing, timekeeping, and navigation. Of particular interest to this NASA solicitation is the transformative potential of quantum technology in the realm of communications. Furthermore, transmission of quantum information over arbitrary distances raises new possibilities in sensing, networked clocks, and distributed quantum computation. The entanglement distribution at the heart of all these applications relies on the same underlying “quantum repeater” technology. ColdQuanta’s objective in this Phase II SBIR is to produce a critical enabling quantum repeater component: a long-lived quantum memory that is strongly coupled to optical fields for storage and recall of single photons.
During Phase I, ColdQuanta investigated generation of atomic ensembles with ultra-high optical density (OD>100) for generation and storage of quantum information because high OD is critical for attaining high memory efficiency. However, the residual atomic motion in the Phase I ensemble results in dephasing of the quantum memory on a timescale of several microseconds, rather than the many milliseconds required for long-range quantum networking. Nevertheless, the Phase I study demonstrated ColdQuanta’s ability to produce high OD ensembles of cold atoms to boost memory efficiency. The remaining task, proposed for Phase II, is to modify the Phase I atom ensemble generation scheme by trapping the atoms in an optical lattice, which limits residual motion and therefore motional dephasing allowing memory lifetimes up to 0.3 seconds to be observed. Development and fabrication of the photon-coupled quantum memory system in Phase II will be highly efficient because the system can be produced by minor modification of ColdQuanta’s existing DoubleMOT commercial product, which comprises the vacuum cell, magnetics, and optics needed to produce cold atom ensembles.
While the explicitly stated NASA application of interest from the solicitation is in quantum communication, the proposed technology enables distribution of entanglement between remote locations which introduces new possibilities not only in quantum communication (long-range secure communication over unsecured channels) but also in quantum networked arrays of clocks (for improved stability, accuracy, and security) and sensors (for example, extension of telescope interferometric baselines improving measurement angular resolution).
An important open question in practical quantum computing is scaling existing systems to vastly larger numbers of qubits than have been demonstrated today. Among the promising candidate solutions to this scaling problem is the idea of employing distributed quantum computing, which extends the achievable size of quantum computing systems in a manner analogous to multi-core classical computing.