Grant: Discovery Grants Program - Individual

This project is to implement fully quantum control over spin-based quantum devices. Spins are some of the most versatile quantum systems and have found applications in sensing, entanglement generation, and as testbeds for quantum computers. The first examples of teleportation, Shor's algorithm and error correction were all done with spins. Today there are a wealth of quantum spin-based sensors being developed for everything from medical devices to navigational tools. Yet despite these developments, much of the power of quantum has not been available with spin processors since spins interact only very weakly with their control system. So weakly in fact, that it is a good approximation to think of the controls as classical. We have developed new control elements and schemes where the spin/controller interaction is strong and the interaction is fully quantum. Having these new tools enables quantum devices that are more efficient, precise and sensitive. The controls are superconducting circuits and, when interacting with spins, provide faster gates and can cool and squeeze spin states on demand. Cooling allows parallel removal of entropy, a key step for all quantum devices and an essential one for quantum error correction. Squeezing allows entanglement generation, more precise sensing, and is the foundation for quantum computing with continuous variables. This advance brings high cooperativity to spin physics. Beyond enabling new control elements for spins it also opens the new area of cavity quantum electrodynamics (QED) in the large-N domain, or spin/cavity physics with lots of spins. We anticipate that this system will become a tool for condensed matter and materials science simulations. The new physics we can experimentally explore include areas of multi-body physics where the theory is intractable. Having a first example of a testbed to explore such physics should bring new insight.Finally, spins are some of the most coherent quantum systems and should make excellent photon storage elements. Having a high cooperativity is a path to using these for microwave storage and potentially photon transduction. It is a possible path to a quantum repeater.