RezQu a Scalable Quantum Computer Architecture Built and its Future Potential

the system’s “scalable” architecture speaks to a bigger future

A 6cm-by-6cm chip holds nine quantum devices, among them four “quantum bits” that do the calculations. The UCSB team said further scaling up to 10 qubits should be possible this year.

AAAS journal Science recognized related work in 2010 as the scientific Breakthrough of the year for his Nature article, “Quantum ground state and single-phonon control of a mechanical resonator”.

A list of UCSB quantum computer publications is here

Session D27: Focus Session: Superconducting Qubits – Gates and Algorithms

March 21, 2011

Experimental demonstration of quantum algorithms on a 4-qubit/5-resonator quantum microprocessor utilizing superconducting qubits in the RezQu architecture by the University of California at Santa Barbara

We present our newly designed and fabricated 4-qubit/5-resonator quantum microprocessor composed of o®-the-shelf” qubit and resonator components in the RezQu architecture. The RezQu architecture uses resonators with qubits in the zero state to turn off stray coupling. Each qubit is coupled to a memory resonator and coupling between the qubits is mediated by a common resonator bus. Eight microwave lines drive the individual qubits, memory resonators, and coupling resonator. We demonstrate control over the quantum microprocessor via small scale quantum algorithms that require executing high-fidelity single qubit gates, quantum Fourier transform, Toffoli, CNOT, and other entangling gates.

Quantum Logic Gates for the Rezqu Architecture by Joydip Ghosh, Michael Geller of the University of Georgia, Athens

A promising quantum computing architecture has been recently proposed by the UCSB superconducting quantum computation group. In this architecture, n phase qubits are capacitively coupled to individual memory resonators as well as a common bus. In this talk we discuss the design of quantum logic gates for this architecture and discuss the intrinsic fidelities.

Idling error and SWAP/MOVE operation in RezQu architecture for phase qubits by Andrei Galiautdinov and Alexander Korotkov University of California – Riverside.

We analyze several basic operations in the RezQu architecture for superconducting phase qubits recently proposed by John Martinis, concentrating on the idling error, generation of single-excitation states, and the single-excitation transfer (which we call MOVE) between a phase qubit and its memory. We show that the idling error is negligible, being proportional to the sixth power of the coupling strength. We also show that in the rotating wave approximation the MOVE operation, which is simpler than the usual SWAP, can be realized perfectly using a tune/detune pulse with four adjustable parameters. The pulse consists of the front ramp (with proper shaping), a constant near-resonant overshoot, and an arbitrary rear ramp.

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