We propose a novel dynamical method for beating decoherence and dissipation in open quantum systems. We demonstrate the possibility of filtering out the effects of unwanted (not necessarily known) system-environment interactions and show that the noise-suppression procedure can be combined with the capability of retaining control over the effective dynamical evolution of the open quantum system. Implications for quantum information processing are discussed.
Dynamical decoupling is a technique that protects qubits against noise. The ability to preserve quantum coherence in the presence of noise is essential for the development of quantum devices. Here the Rigetti quantum computing platform was used to test different dynamical decoupling sequences. The performance of the sequences was characterized by Quantum Process Tomography and analyzed using the quantum channels formalism. It is shown that dynamical decoupling can reduce qubit dephasing but cannot protect against spontaneous emission. Furthermore, from process tomography results, it was also p…
Periodic deterministic bang-bang dynamical decoupling and the quantum Zeno effect are known to emerge from the same physical mechanism. Both concepts are based on cycles of strong and frequent kicks provoking a subdivision of the Hilbert space into independent subspaces. However, previous unification results do not capture the case of random bang-bang dynamical decoupling, which can be advantageous to the deterministic case but has an inherently acyclic structure. Here, we establish a correspondence between random dynamical decoupling and the quantum Zeno effect by investigating the average ov…
The main obstacles to the realization of high-fidelity quantum gates are the control errors arising from inaccurate manipulation of a quantum system and the decoherence caused by the interaction between the quantum system and its environment. Nonadiabatic holonomic quantum computation allows for high-speed implementation of whole-geometric quantum gates, making quantum computation robust against control errors. Dynamical decoupling provides an effective method to protect quantum gates against environment-induced decoherence, regardless of collective decoherence or independent decoherence. In t…
Quantum information processing with multi-level systems (qudits) provides additional features and applications than the two-level systems. However, qudits are more prone to dephasing and dynamical decoupling for qudits has never been experimentally demonstrated. Here, as a proof-of-principle demonstration, we experimentally apply dynamical decoupling to protect superpositions with three levels of a trapped $^9\rm{Be}^+$ ion from ambient noisy magnetic field, prolonging coherence by up to approximately an order of magnitude. Our demonstration, straightforwardly scalable to more levels, may open…
Selective recoupling and stochastic dynamical decoupling
提出了一种嵌入式选择性重耦合方法,该方法基于将Yamaguchi等人[quant-ph/0411099]最近提出的确定性选择性重耦合方案嵌入到随机动态解耦方法中的思想,例如最近提出的Pauli-random-error-correction-(PAREC)方案[Eur. J. D 32,153,quant-ph/0407262]。再耦合方案通过部分抑制不需要的相互作用使得能够在量子信息处理器中实现基本量子门。随机动力学解耦方法取消了很大一部分残余相互作用。因此,可靠的量子计算的时间尺度显着增加。数值模拟的条件两量子比特交换门和复杂的迭代量子算法。
Non-Markovian Quantum Error Deterrence by Dynamical Decoupling in a General Environment
研究了一种动态解耦方案,用于阻止非马尔可夫(通常对应于低温、短时间和强耦合)机制中的错误,该机制适用于由多级结构构造的量子比特。我们采用最近提出的有效自旋玻色子模型[K.盐川和B. L. Hu,Phys.Rev.A70,062106(2004)]作为量子布朗振子模型的低温极限,其中可以获得具有色噪声的一般环境的精确解。在我们的解耦方案中,一个训练的强脉冲对被用来发展的相互作用哈密顿量瞬间。使用此方案,我们表明,动态解耦方法可以抑制$1/f$噪声与更慢,因此更容易访问的脉冲比以前的研究,但它仍然未能解耦超欧姆类型的环境。
In the quantum-computation scenario, geometric phase-gates are becoming increasingly attractive for their intrinsic fault tolerance to disturbance. With an adiabatic cyclic evolution, Berry phase appears to realize a geometric transformation. Performing the quantum gates as many as possible within the timescale of coherence, however, remains an inconvenient bottleneck due to the systematic errors. Here we propose an accelerated adiabatic quantum gate based on the Berry phase, the transitionless driving, and the dynamical decoupling. It reconciles a high fidelity with a high speed in the presen…
Improvement of performance of Grover's algorithm on three generations of Heron family IBM QPUs without and with topological dynamical decoupling
Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences(保加利亚科学院固体物理格奥尔基·纳贾科夫研究所);Center for Quantum Technologies, Department of Physics, St. Kliment Ohridski University of Sofia(索非亚圣克利门特·奥赫里德斯基大学物理学院量子技术中心)