Enhanced electron-phonon coupling for a semiconductor charge qubit in a surface phonon cavity

Vasileios N. Stavrou, Xuedong Hu

Arkady Fedorov, Leonid Evgenevich Fedichkin, Vladimir Privman A

Ying-Yen Liao, Y. N. Chen, W. C. Chou +1 more

This study elucidates the theory of phonon-induced decoherence of a double dot charge qubit that is embedded inside a suspended semiconductor slab. The influences of the lattice temperature, width of the slab, and positions of the dots on the decoherence are analyzed. Numerical results indicate that the decoherence in the slab system is weaker than that in a bulk environment. In particular, the decoherence is markedly suppressed by the inhibition of the electron-phonon coupling. Such a system with low decoherence may be useful for manipulating the qubits.

Wenming Ju, Ka‐Di Zhu, Peihao Huang +1 more

Öney O. Soykal, Rusko Ruskov, Charles Tahan

Xuedong Hu, Belita Koiller, S. Das Sarma

We consider charge qubits based on shallow donor electron states in silicon and coupled quantum dots in GaAs. Specifically, we study the feasibility of ${P}_{2}^{+}$ charge qubits in Si, focusing on single qubit properties in terms of tunnel coupling between the two phosphorus donors and qubit decoherence caused by electron-phonon interaction. By taking into consideration the multivalley structure of the Si conduction band, we show that intervalley quantum interference has important consequences for single-qubit operations of ${P}_{2}^{+}$ charge qubits. In particular, the valley interference leads to a tunnel-coupling strength distribution centered around zero. On the other hand, we find that the Si band structure does not dramatically affect the electron-phonon coupling and consequently, qubit coherence. We also critically compare charge qubit properties for $\mathrm{Si}:{P}_{2}^{+}$ and GaAs double quantum dot quantum computer architectures.