Iterative rotation scheme for robust dynamical decoupling | Phys. Rev. A 85, 052324 (2012)

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

Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
Received 1 March 2012; published 29 May 2012

The loss of quantum information due to interactions with external degrees of freedom, which is known as decoherence, remains one of the main obstacles for large-scale implementations of quantum computing. Accordingly, different measures are being explored for reducing its effect. One of them is dynamical decoupling DD which offers a practical solution because it only requires the application of control pulses to the system qubits. Starting from basic DD sequences, more sophisticated schemes were developed that eliminate higher-order terms of the system-environment interaction and are also more robust against experimental imperfections. A particularly successful scheme, called concatenated DD CDD, gives a recipe for generating higher-order sequences by inserting lower-order sequences into the delays of a generating sequence. Here, we show how this scheme can be improved further by converting some of the pulses to virtual and thus ideal pulses. The resulting scheme, called (XY4)^n, results in lower power deposition and is more robust against pulse imperfections than the original CDD scheme.

©2012 American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevA.85.052324
DOI: 10.1103/PhysRevA.85.052324

via Phys. Rev. A 85, 052324 2012: Iterative rotation scheme for robust dynamical decoupling.

 

Normalized spin-signal after about 100 pulses for different DD sequences as a function of the RF frequency of the DD pulses and the delay between them. All sequences have 100 pulses except (XY4)^2, which contains 96. The labels (a) and (s) refers the the asymmetric and symmetric version of the sequences. The plot shows that our concatenation scheme with virtual pulses (XY4)^2 outperforms the concatenation scheme with real pulses CDD_2. Following a similar procedure we introduce a new sequence KDD^2 that outperforms the other DD sequences shown in the plot. This new sequence is based on the KDD sequence [PRL 106, 240501 (2011)].
Normalized spin-signal after about 100 pulses for different DD sequences as a function of the RF frequency of the DD pulses and the delay between them. All sequences have 100 pulses except (XY4)^2, which contains 96. The labels (a) and (s) refers the the asymmetric and symmetric version of the sequences. The plot shows that our concatenation scheme with virtual pulses (XY4)^2 outperforms the concatenation scheme with real pulses CDD_2. Following a similar procedure we introduce a new sequence KDD^2 that outperforms the other DD sequences shown in the plot. This new sequence is based on the KDD sequence [PRL 106, 240501 (2011)].
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