Month: March 2012

WordPress Blog

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Hi all,

I have created this blog at https://gaalvarez.wordpress.com for updates about my last publications and news. I was using before other method for RSS feeds, but it is no longer being supported. So, I am slowly moving to this blog for that purpose. You can subscribe here to RSS feeds or email notifications.

I hope you will find it interesting.

Gonzalo.

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Effects of time-reversal symmetry in dynamical decoupling | Phys. Rev. A 85, 032306 2012

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Alexandre M. Souza, Gonzalo A. Álvarez, and Dieter Suter

Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany

Received 15 December 2011; published 7 March 2012

Dynamical decoupling is a technique for preserving the coherence of quantum-mechanical states in the presence of a noisy environment. It uses sequences of inversion pulses to suppress the environmental perturbations by periodically refocusing them. It has been shown that different sequences of inversion pulses show vastly different performance, in particular also concerning the correction of experimental pulse imperfections. Here, we investigate specifically the role of time-reversal symmetry in the building blocks of the pulse sequence. We show that using time-symmetric building blocks often improves the performance of the sequence compared to sequences formed by time-asymmetric building blocks. Using quantum state tomography of the echoes generated by the sequences, we analyze the mechanisms that lead to loss of fidelity and show how they can be compensated by suitable concatenation of symmetry-related blocks of decoupling pulses.©2012 American Physical Society

via Phys. Rev. A 85, 032306 2012: Effects of time-reversal symmetry in dynamical decoupling.

Evolution of the magnetization during the symmetric (S) and asymmetric (A) versions of the XY-16 sequence for pulse spacings of τ = 10μs. The panels represents the Bloch vector in the xy plane at different times. The color code in the lower panel denotes the time evolution, blue for the initial state and red for the final state.
Evolution of the magnetization during the symmetric (S) and asymmetric (A) versions of the XY-16 sequence for pulse spacings of τ = 10μs. The panels represents the Bloch vector in the xy plane at different times. The color code in the lower panel denotes the time evolution, blue for the initial state and red for the final state.