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Blind quantum computing is a promising application of distributed quantum systems, in which a client can perform computations on a remote server without revealing any details of the applied circuit. Although the most promising realizations of quantum computers are based on various matter-qubit platforms, implementing blind quantum computing on matter qubits remains a challenge. Using silicon-vacancy (SiV) centers in nanophotonic diamond cavities with an efficient optical interface, we demonstrated a universal quantum gate set consisting of single- and two-qubit blind gates over a distributed two-node network. Using these ingredients, we performed a distributed algorithm with blind operations across our two-node network, proving a route to develop blind quantum computation with matter qubits in distributed, modular architectures. 

Color centers have emerged as a leading qubit candidate for realizing hybrid spin-photon quantum information technology. One major limitation of the platform, however, is that the characteristics of individual color centers are often strain dependent. As an illustrative case, the silicon-vacancy center in diamond typically requires millikelvin temperatures in order to achieve long coherence properties, but strained silicon-vacancy centers have been shown to operate at temperatures beyond 1 K without phonon-mediated decoherence. In this work, we combine high-stress silicon-nitride thin films with diamond nanostructures to reproducibly create statically strained silicon-vacancy color centers (mean ground state splitting of 608 GHz) with strain magnitudes of ∼4×10−4. Based on modeling, this strain should be sufficient to allow for operation of a majority silicon-vacancy centers within the measured sample at elevated temperatures (1.5 K) without any degradation of their spin properties. This method offers a scalable approach to fabricate high-temperature operation quantum memories. Beyond silicon-vacancy centers, this method is sufficiently general that it can be easily extended to other platforms as well. 

A quantum network node combining a long-lived memory, robust optical interface, and integrated error detection is realized.