Several algorithms that would theoretically provide a significant speed-up when performed on a quantum computer over a classical computer require random access memory (RAM). A RAM enables quick retrieval, in any order, of data stored in a memory array. Unlike a classical RAM, the input and output registers of a quantum RAM (QRAM) use quantum bits rather than conventional bits, the memory array in a QRAM can be classical or quantum depending on the usage, and a QRAM can address a superposition of memory cells and return a superposition of the data. No such QRAM currently exists. The availability of a QRAM would enable implementation of various quantum algorithms and herald potentially ground-breaking capabilities impossible to achieve classically.
The aim of this Department of Defense (DoD) Multidisciplinary University Research Initiative (MURI) topic is to understand and create an efficient QRAM with quantum addressing of data stored in an array of memory cells. This will include close collaboration between theory and experiment to develop and implement novel protocols to perform fundamental QRAM operations with minimal computational complexity.