The researchers have developed a method that revolutionizes the performance and stability of quantum systems. By addressing critical issues such as decoherence and control errors, this innovative approach enhances coherence time by tenfold, improves control fidelity, and boosts sensitivity in quantum sensing.
Quantum technologies, from quantum computers to advanced sensors, have the potential to transform fields like computing, cryptography, and medical imaging. However, noise has been a significant obstacle, disrupting quantum states and introducing errors. Traditional methods of noise mitigation, focusing on temporal autocorrelation, have been somewhat effective but limited.
Researchers, including Ph.D. student Alon Salhov under the guidance of Prof. Alex Retzker from Hebrew University, alongside Qingyun Cao from Ulm University and Prof. Jianming Cai from Huazhong University of Science and Technology, have devised a novel strategy. Their method leverages the cross-correlation between two noise sources, utilizing destructive interference to significantly extend the coherence time of quantum states and enhance sensitivity for high-frequency quantum sensing.
Schematic representation of destructive interference of cross-correlated noise, control sequences and experimental setup. Detailed description (from the paper):
(a) The qubit is subjected to environmental noise δ(t). Applying a resonant drive with Rabi frequency ? 1 creates a protected dressed qubit which decoheres mainly due to ε1(t) – the amplitude noise in ? 1. Applying a second drive with modulation frequency e? 1, Rabi frequency ? 2 and amplitude fluctuations ε2(t), reduces decoherence due to ε1(t).
(b) If the cross-correlation, c, of ε1(t) and ε2(t) is nonzero, a detuning e? 1 = ? 1 + c ? 2 2/? 1 tilts the effective-drive axis and induces a destructive interference of the cross-correlated noise, resulting in a doubly-dressed qubit with a longer coherence time.
(c) Measurement sequences for standard and correlated double drive (DD) protocols. (d) Experimental setup and level
scheme of the NV center.
Key achievements of this new strategy include:
1. Tenfold Increase in Coherence Time: Quantum information now remains intact ten times longer than with previous methods.
2. Improved Control Fidelity: Enhanced precision in manipulating quantum systems results in more accurate and reliable operations.
3. Superior Sensitivity: The ability to detect high-frequency signals surpasses current technologies, enabling new applications in quantum sensing.
Alon Salhov commented, “Our innovative approach extends our toolbox for protecting quantum systems from noise. By focusing on the interplay between multiple noise sources, we’ve unlocked unprecedented levels of performance, bringing us closer to the practical implementation of quantum technologies.”
This advancement is not just a significant leap for quantum research but also holds promise for various industries. Fields that rely on highly sensitive measurements, such as healthcare, stand to benefit enormously from these improvements.
“Protecting Quantum Information via Destructive Interference of Correlated Noise” by Alon Salhov, Qingyun Cao, Jianming Cai, Alex Retzker, Fedor Jelezko, and Genko Genov, 30 May 2024, Physical Review Letters.
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