SBIR-STTR Award

The future of secure ground-space and space-space communications relies on development of quantum secure communications (QSC) systems. ColdQuanta proposes to develop QSC devices based on compact, robust vacuum systems containing dense ensembles of cold, trapped rubidium atoms. In particular, we propose to develop a source of high-flux, high-coherence entangled photon pairs (biphotons). These biphotons can be used to transmit information in a provably secure manner that is consistent with existing QKD protocols and other real-time secure information transfer protocols. The proposed atomically sourced biphotons outperform photon pairs from existing solid-state sources by over a factor of 1000 in coherence time and spectral linewidth. The narrow spectral linewidth of the atomically sourced biphotons makes them compatible with direct interfacing with downstream atomic systems, opening vast new vistas in the potential for long-range QSC and quantum networking. A second direction that further pushes the state-of-the-art in highly-coherent quantum optical systems for QSC is our second proposed device that provides efficient storage and recall of single-photon states. The single photons are stored in a coherent collective excitation of a cold atomic ensemble and can later be retrieved when the downstream QSC system is ready. Together, these devices represent a dramatic step forward in the quality of commercially available QSC hardware components. Nevertheless, the parallel development of the devices will be highly efficient due to their shared reliance on identical underlying cold atom hardware. These devices (and potentially several other related quantum optical devices) will be different laser and optical packages wrapped around an identical vacuum system for production of atomic ensembles with extremely high optical density. Phase I will demonstrate the underlying atom ensemble hardware and will complete system-level designs of the proposed QSC hardware components. Potential NASA Applications Quantum communications provides provably secure transmission of information, something that can’t be ensured in any other way. Thus, the future of ground-space and space-space communication will be performed over quantum links. The Chinese MICIUS satellite has paved the initial path in the direction of employing quantum protocols for secure communications. The innovation proposed here would provide part of the necessary package for NASA to return to the fore-front of secure space communications. Potential Non-NASA Applications Implementing and utilizing quantum communication technologies (QCT) is of great interest to companies and governmental entities that transfer highly sensitive information as part of their operations (such as government agencies, financial and research firms, medical companies, stock trading services, etc.). The benefits provided by the proposed technology position it well for rapid integration into existing quantum communications applications.

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. Potential NASA Applications (Limit 1500 characters, approximately 150 words) 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). Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) 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.