Quantum computer with CPU and memory breakthrough

To date, quantum computers have been implemented so that programming their operation was, in essence, hardwired into their essential structure. Although many useful demonstrations of quantum computing have resulted from such special-purpose devices, they are basically one-problem computers which cannot easily be reprogrammed or scaled to attack larger problems. As early models of practical quantum computers, they don’t make the grade.
The basis of essentially all practical classical computers is the Von Neumann architecture, which comprises a central processing unit (CPU) to do calculations, a memory which holds both data and CPU instructions, and an interface which allows the input and output of the CPU to change the information in memory. This architecture is easily scalable to nearly any size and capacity desired.
Recently, John Martinis’ research group at the University of California at Santa Barbara has created the first general-purpose programmable quantum computer.
Their quantum computer uses superconducting circuits to form quantum computer equivalent of a Von Neumann architecture.
The result is the first universal (general purpose) quantum computer. To illustrate the importance of this design, the UCSB circuit, which has two qubit registers and two entangled memories, has been used to simulate a three-qubit logic gate. Such ability to solve problems having more active information than the capacity of the CPU is enabled by implementation of the Von Neumann architecture.
How quantum computers work
The irreducible carrier of quantum information is the qubit, named in analogy to the classical bit. But whereas the bit is a simple on-off signal, a qubit is in essence a unit vector whose direction is described by a pair of angles, θ and Φ. These angles describe the superposition of pure quantum states which makes up the quantum information in the qubit. While a bit defines a single binary parameter (+ 1), a qubit defines a continuous complex variable.
When a quantum operation is carried out on a qubit, these angles change, thereby changing the quantum information in that qubit. All quantum computation in the end reduces to combined rotations of quantum states.