Special Condensed Matter Physics Seminar

Note Special Time and Place!
10:30 a.m., Tuesday, February 10, 2004
Room 2202, Physics Building

 Quantum computation by dispersive dynamics

Xingxiang Zhou

(University of Rochester)

Abstract:  Among the many challenges in the construction of a quantum computer, the need to suppress decoherence and simplify operation seems the most critical. In this talk, we present a new method for robust and easy quantum computation based on dispersive manipulation of encoded qubits. We apply our scheme to superconducting qubits, which have shown great potential experimentally but are under the suspicion that they will fail eventually because of the severe decoherence and lack of switchable couplings intrinsic to the technology. We establish a decoherence free subspace (DFS) on paired superconducting charge boxes (PCB) sharing a common bias lead, and we manipulate the PCB system by its dispersive interaction with a virtually excited LC resonator. By making use of the dispersive phases induced by the inductive coupling between PCBs, we can implement entangling gates between PCBs and thus realize universal quantum computation on the PCB system. Our scheme reduces the requirement for DFS quantum computation to the established local symmetry only, which makes it appealing to scalable solid state systems. The only control required for computation is controlling the voltage bias of the PCBs. The principle of dispersive manipulation of encoded qubits is general and applicable to many other physical systems.
Host:  Das Sarma
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