Quantum computation with noisy operations

Abstract

In this paper, we show how to use low-fidelity operations to control the dynamics of quantum systems. Noisy operations usually drive a system to evolve into a mixed state and damage the coherence. Sometimes frequent noisy operations result in the coherent evolution of a subsystem, and the dynamics of the subsystem is controlled by tuning noisy operations. Based on this, we find that universal quantum computation can be carried out by low-fidelity (fidelity < 90%) operations.

Population trapping: The mechanism for the lost resonance lines in Pm-like ions

“…The resonance line of W 13+ has tentatively been identified in spectra measured at Berlin-EBIT [7,8]. However, we exclude the data from the present comparison because the identification in [7,8] is controversial [17,20]. Kobayashi et al [15] reported that the corresponding line was not observed in the predicted region measured by…”

“…While they observed weak resonance lines in the spectra except for tungsten, the emission spectra for all of the elements they studied are dominated by the transitions. Li et al [17] assigned other Pm-like lines prominent in tungsten spectra measured by high-temperature superconducting EBIT (SH-HtscEBIT) to and transitions. However, the assignment is inconsistent with that by Kobayashi et al [16].…”

Measurement‐Based Hyperentanglement Distillation for Lossy and Distortion Photon State

“…In particularly, the QAP can be used to decrease the weigh of vacuum state component in nonlocal mixed hyperentangled state and increase the quality of nonlocal hyperentangled photon system. [56,57] Hyperentanglement concentration protocol (hyper-ECP) [58][59][60][61] and hyperentanglement purification protocol (hyper-EPP) [62][63][64][65] have been used to distill high-quality nonlocal hyperentangled photon systems from a set of nonlocal photon systems in partially hyperentangled pure state and mixed hyperentangled state (composite of maximally hyperentangled states), respectively.…”

One-step implementation of multiqubit controlled–controlled-Z gates with Rydberg atoms

“…In recent years, quantum computing has attracted many interests [1][2][3][4], and is considered to be superior to classical computation in solving many practical problems, such as factoring large integers [5] and searching unsorted databases [6]. Quantum logic gates are the key component to put quantum computing into practice.…”