### UCSB physicists demonstrate ‘quantum von Neumann’ architecture

##### September 2, 2011

UC Santa Barbara (UCSB) physicists have demonstrated a new paradigm in quantum information processing with a quantum integrated circuit that implements a “quantum von Neumann” architecture.

In this architecture, a long-lived quantum random access memory can be programmed using a quantum central processing unit, all constructed on a single chip, providing the key components for a quantum version of a classical computer.

“Computational steps take a few billionths of a second, comparable to a classical computer, but the great power is that a quantum computer can perform a large number of calculations simultaneously,” said Matteo Mariantoni, postdoctoral fellow in the UCSB Department of Physics.

“In our new UCSB architecture we have explored the possibility of writing quantum information to memory, while simultaneously performing other quantum calculations,” he said.

“On the quantum von Neumann architecture, we were able to run the quantum Fourier transform and a three-qubit Toffoli gate — key quantum logic circuits for the further development of quantum computing.”

This research has also been covered by *New Scientist*: “Previously, setups using photons or trapped ions as qubits have made the most headway in early calculations. Now Matteo Mariantoni of the University of California, Santa Barbara, and colleagues have boosted the computing power of a rival design, first demonstrated in 2003, that uses tiny, superconducting wires instead.”

Ref.: Matteo Mariantoni et al., Implementing the Quantum von Neumann Architecture with Superconducting Circuits, *Science Express*, September 2011 [DOI:10.1126/science.1208517]