Robustness of Decoherence-Free States for Charge Qubits under Local Non-uniformity
arXiv:cond-mat/0412694 · doi:10.1103/PhysRevB.72.085335
Abstract
We analyze the robustness of decoherence-free (DF) subspace and subsystem in charge qubits, when difference from the collective decoherence measurement condition is large in the long time period, which is applicable for solid-state qubits using as a quantum memory. We solve master equations of up to four charge qubits and a detector as a quantum point contact (QPC). We show that robustness of DF states is strongly affected by local non-uniformities. We also discuss the possible two-qubit logical states by exactly solving the master equations.
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