Quantum mechanics describes the physical world around us with exquisite precision, with no known violations of the theory. Ironically, this precision comes with some additional baggage: the theory permits the existence of a host of complex, delicate entangled states of the physical world, many of which have yet to be produced or observed. The debate of whether their quantum entanglement really captures the fundamental nature of the physical world and is an engineering resource is reaching a critical moment. Quantum processors with of order 100 qubits based on superconducting circuitry have recently demonstrated computing power on par with the most advanced classical supercomputers for select problems. Current hardware is, however, prone to errors from materials defects, imperfect control systems, and the leakage of quantum information into unwanted modes in the solid-state. I will describe the major decoherence pathways present in state-of-the-art superconducting quantum processors, illustrate techniques to maximize the computing power of imperfect qubits, and introduce including new architectures using qutrits and ququarts.
