Dynamical decoupling

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Short description: Quantum coherency control technique for quantum computing

Dynamical decoupling (DD) is an open-loop quantum control technique employed in quantum computing to suppress decoherence by taking advantage of rapid, time-dependent control modulation. In its simplest form, DD is implemented by periodic sequences of instantaneous control pulses, whose net effect is to approximately average the unwanted system-environment coupling to zero.[1][2] Different schemes exist for designing DD protocols that use realistic bounded-strength control pulses,[3] as well as for achieving high-order error suppression,[4][5] and for making DD compatible with quantum gates.[6][7][8] In spin systems in particular, commonly used protocols for dynamical decoupling include the Carr-Purcell and the Carr-Purcell-Meiboom-Gill schemes.[9][10] They are based on the Hahn spin echo technique of applying periodic pulses to enable refocusing and hence extend the coherence times of qubits. Periodic repetition of suitable high-order DD sequences may be employed to engineer a 'stroboscopic saturation' of qubit coherence, or coherence plateau, that can persist in the presence of realistic noise spectra and experimental control imperfections. This permits device-independent, high-fidelity data storage for computationally useful periods with bounded error probability.[11]

Dynamical decoupling has also been studied in a classical context for two coupled pendulums whose oscillation frequencies are modulated in time.[12]

References

  1. ↑ Viola, L.; Lloyd, S. (1998). "Dynamical suppression of decoherence in two-state quantum systems". Physical Review A 58 (4): 2733–2744. doi:10.1103/PhysRevA.58.2733. Bibcode: 1998PhRvA..58.2733V. 
  2. ↑ Viola, L.; Knill, E.; Lloyd, S. (1999). "Dynamical Decoupling of Open Quantum Systems". Physical Review Letters 82 (12): 2417–2421. doi:10.1103/PhysRevLett.82.2417. Bibcode: 1999PhRvL..82.2417V. 
  3. ↑ Viola, L.; Knill, E. (2003). "Robust Dynamical Decoupling of Quantum Systems with Bounded Controls". Physical Review Letters 90 (3): 037901. doi:10.1103/PhysRevLett.90.037901. PMID 12570525. Bibcode: 2003PhRvL..90c7901V. 
  4. ↑ Khodjasteh, K.; Lidar, D. (2005). "Fault-Tolerant Quantum Dynamical Decoupling". Physical Review Letters 95 (18): 180501. doi:10.1103/PhysRevLett.95.180501. PMID 16383882. Bibcode: 2005PhRvL..95r0501K. 
  5. ↑ Uhrig, G. S. (2007). "Keeping a Quantum Bit Alive by Optimized π-Pulse Sequences". Physical Review Letters 98 (10): 100504. doi:10.1103/PhysRevLett.98.100504. PMID 17358521. Bibcode: 2007PhRvL..98j0504U. 
  6. ↑ Viola, L.; Lloyd, S.; Knill, E. (1999). "Universal Control of Decoupled Quantum Systems". Physical Review Letters 83 (23): 4888–4891. doi:10.1103/PhysRevLett.83.4888. Bibcode: 1999PhRvL..83.4888V. 
  7. ↑ West, J. R.; Lidar, D. A.; Fong, B. H.; Gyure, M. F. (2011). "High Fidelity Quantum Gates via Dynamical Decoupling". Physical Review Letters 105 (23): 230503. doi:10.1103/PhysRevLett.105.230503. PMID 21231440. Bibcode: 2010PhRvL.105w0503W. 
  8. ↑ Yang, W.; Wang, Z. Y.; Liu, R. B. (2010). "Preserving qubit coherence by dynamical decoupling". Frontiers of Physics 6 (1): 2–14. doi:10.1007/s11467-010-0113-8. Bibcode: 2011FrPhy...6....2Y. 
  9. ↑ Carr, H. Y.; Purcell, E. M. (1954-05-01). "Effects of Diffusion on Free Precession in Nuclear Magnetic Resonance Experiments". Physical Review 94 (3): 630–638. doi:10.1103/PhysRev.94.630. Bibcode: 1954PhRv...94..630C. 
  10. ↑ Meiboom, S.; Gill, D. (1958-08-01). "Modified Spin‐Echo Method for Measuring Nuclear Relaxation Times". Review of Scientific Instruments 29 (8): 688–691. doi:10.1063/1.1716296. ISSN 0034-6748. Bibcode: 1958RScI...29..688M. 
  11. ↑ Khodjasteh, K.; Sastrawan, J.; Hayes, D.; Green, T. J.; Biercuk, M. J.; Viola, L. (2013). "Designing a practical high-fidelity long-time quantum memory". Nature Communications 4: 2045. doi:10.1038/ncomms3045. PMID 23784079. Bibcode: 2013NatCo...4.2045K. 
  12. ↑ Salerno, Grazia; Carusotto, Iacopo (2014). "Dynamical decoupling and dynamical isolation in temporally modulated coupled pendulums" (in en). EPL 106 (2): 24002. doi:10.1209/0295-5075/106/24002. ISSN 0295-5075. Bibcode: 2014EL....10624002S. http://stacks.iop.org/0295-5075/106/i=2/a=24002. 
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