Ions, atoms, and bits: An architectural approach to quantum computing

Computing with quantum states may be the most efficient approach to solving some problems that take exponential time on conventional computers. Quantum states, however, are short-lived without constant error correction. Furthermore, the classical control required by proposed quantum schemes imposes constraints on how a quantum computer can be built. This chapter focuses on a basic architectural requirement for any computation-communication. Unlike classical signals, quantum data cannot be simply transmitted over a wire, but must be moved step-wise from location to adjacent location. We start with a brief overview of quantum computing operations, error correction, and algorithms. Next we analyze a straightforward communication mechanism-the swapping channel. We compare the swapping channel with a longer-range communication mechanism-the teleportation channel. We finish out the chapter with a discussion of error correction. Error correction is necessary to avoid data corruption. We look in detail at its architectural implications and analyze the associated overhead.