Protecting qubit coherence by spectrally engineered driving of the spin environment

Abstract

Modern quantum technologies rely crucially on techniques to mitigate quantum decoherence; these techniques can be either passive, achieved for example via materials engineering, or active, typically achieved via pulsed monochromatic driving fields applied to the qubit. Using a solid-state defect spin coupled to a microwave-driven spin bath, we experimentally demonstrate a decoherence mitigation method based on spectral engineering of the environmental noise with a polychromatic drive waveform, and show that it outperforms monochromatic techniques. Results are in agreement with quantitative modeling, and open the path to active decoherence protection using custom-designed waveforms applied to the environment rather than the qubit.

Probing many-body dynamics in a two-dimensional dipolar spin ensemble

“…Polychromatic drive. The polychromatic drive was generated by phase modulating the resonant P1 microwave tone 67 . A random array of phase jumps Δθ was pre-generated and loaded onto an arbitrary waveform generator controlling the IQ modulation ports of a signal generator.…”

Roadmap on nanoscale magnetic resonance imaging

“…encapsulation and termination) and Fermi level engineering approaches that, importantly, need to preserve nanometer-scale sensor-target separations. A complementary approach, which resigns itself to the presence of surface nonidealities, involves the in-situ manipulation of magnetic-noise sources and charge traps such as DC electric field biasing or surface spin driving or DC electric field biasing [147,148].…”

“…Higher collection efficiencies can facilitate the use of other advanced readout techniques such as spin-to-charge readout [152], resonant readout [148], and nuclear-assisted repetitive readout schemes [153], which are especially useful for measurements with long sensing times, such as T1-relaxometry imaging or AC measurements with long T 2 times, as shown in figure 12(c).…”

Diamond surface engineering for molecular sensing with nitrogen—vacancy centers

“…Essentially, such driving shifts the center of the magnetic noise spectrum from f = 0 to f = Ω , which can reduce the spectral overlap with the NV measurement window, 10 resulting in an increased NV coherence time. Noise can be reduced further by spectral engineering of the applied field 342 or by using pulsed schemes. 340,343…”