Quantum decoherence of a charge qubit in a spin-fermion model - Condensed Matter > Mesoscale and Nanoscale PhysicsReportar como inadecuado




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Abstract: We consider quantum decoherence in solid-state systems by studying thetransverse dynamics of a single qubit interacting with a fermionic bath anddriven by external pulses. Our interest is in investigating the extent to whichthe lost coherence can be restored by the application of external pulses to thequbit. We show that the qubit evolution under various pulse sequences can bemapped onto Keldysh path integrals. This approach allows a simple diagrammatictreatment of different bath excitation processes contributing to qubitdecoherence. We apply this theory to the evolution of the qubit coupled to theAndreev fluctuator bath in the context of widely studied superconductingqubits. We show that charge fluctuations within the Andreev-fluctuator modellead to a 1-f noise spectrum with a characteristic temperature depedence. Wediscuss the strategy for suppression of decoherence by the application ofhigher-order beyond spin echo pulse sequences.



Autor: R. M. Lutchyn, L. Cywinski, Cody P. Nave, S. Das Sarma

Fuente: https://arxiv.org/







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