Measuring the Spectrum of Colored Noise by Dynamical Decoupling | Phys. Rev. Lett. 107, 230501 (2011)
Measuring the Spectrum of Colored Noise by Dynamical Decoupling
Gonzalo A. Álvarez* and Dieter Suter†
Fakultät Physik, Technische Universität Dortmund, D-44221 Dortmund, Germany
Received 12 June 2011; published 30 November 2011
Decoherence is one of the most important obstacles that must be overcome in quantum information processing. It depends on the qubit-environment coupling strength, but also on the spectral composition of the noise generated by the environment. If the spectral density is known, fighting the effect of decoherence can be made more effective. Applying sequences of inversion pulses to the qubit system, we developed a method for dynamical decoupling noise spectroscopy. We generate effective filter functions that probe the environmental spectral density without requiring assumptions about its shape. Comparing different pulse sequences, we recover the complete spectral density function and distinguish different contributions to the overall decoherence.
© 2011 American Physical Society