Daxiu Wei
Chinese Academy of Sciences
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Publication
Featured researches published by Daxiu Wei.
Physical Review A | 2014
Haidong Yuan; Daxiu Wei; Yajuan Zhang; Steffen J. Glaser; Navin Khaneja
Experiments in coherent nuclear and electron magnetic resonance,and quantum computing in general correspond to control of quantum mechanical systems, guiding them from initial to final target states by unitary transformations. The control inputs (pulse sequences) that accomplish these unitary transformations should take as little time as possible so as to minimize the effects of relaxation and decoherence and to optimize the sensitivity of the experiments. Here, we derive a time-optimal sequences as fundamental building blocks for synthesize unitary transformations. Such sequences can be widely implemented on various physical systems, including the simulation of effective Hamiltonians for topological quantum computing on spin lattices. Experimental demonstrations are provided for a system consisting of three nuclear spins.
Chinese Science Bulletin | 2003
Daxiu Wei; Jun Luo; Xianping Sun; Xizhi Zeng; Xiaodong Yang; Maili Liu; Shangwu Ding
In this study, we report the experimental realization of seven-qubit Deutsch-Jozsa (D-J) algorithm and controlled phase-shift gates with improved precision using liquid state nuclear magnetic resonance (NMR). The experimental results have shown that transformationsUf in the seven-qubit D-J algorithm have been implemented with different pulse sequences, and whetherf is constant or balanced is determined by using only a single function call (Uf). Furthermore, we propose an experimental method to measure and correct the error in the controlled phase-shift gate that is simple and feasible in experiments, and can have precise phase shifts. These may offer the possibility of surmounting the difficulties of low signal-to-noise ratio (SNR) in multi-qubit NMR quantum computers, more complicated experimental techniques, and the increase of gate errors due to using a large number of imperfect selective pulses. These are also applied to more complicated quantum algorithms with more qubits, such as quantum Fourier transformation and Shor’s algorithm.
Physical Review Letters | 2005
Daxiu Wei; Jun Luo; Xianping Sun; Xizhi Zeng; Mingsheng Zhan; Maili Liu
This Letter presents a two-dimensional nuclear magnetic resonance (NMR) approach for constructing a two-logical-qubit decoherence-free subspace (DFS) by using four multiple-quantum coherences of a CH3 spin system as logical qubits. The three protons in this spin system are magnetically equivalent and can only be used as a single qubit in one-dimensional NMR. We have experimentally demonstrated that our DFS can protect against more types of decoherences than those of the one composed of four noisy physical qubits all with different chemical shifts. This idea may provide new insights into extending qubit systems in the sense that it effectively utilizes the magnetically equivalent nuclei.
Applied Physics Letters | 2014
Daxiu Wei; Yan Chang; Steffen J. Glaser; Xiaodong Yang
Using an extended version of the optimal-control-based gradient ascent pulse engineering algorithm, cooperative (COOP) pulses are designed for multi-scan experiments to prepare pseudo-pure states in quantum computation. COOP pulses can cancel undesired signal contributions, complementing and generalizing phase cycles. They also provide more flexibility and, in particular, eliminate the need to select specific individual target states and achieve the fidelity of theoretical limit by flexibly choosing appropriate number of scans and duration of pulses. The COOP approach is experimentally demonstrated for three-qubit and four-qubit systems.
Chinese Physics Letters | 2002
Jun Luo; Daxiu Wei; Li Xiao; Xizhi Zeng
We propose a simple scheme to create entangled states and realize information transmission between qubits with non-direct interactions on the basis of quantum superdense coding and swap operations. This may offer the possibility of applications in scalable quantum computers.
Chinese Physics | 2004
Daxiu Wei; Jun Luo; Xiaodong Yang; Xianping Sun; Xizhi Zeng; Maili Liu; Shangwu Ding; Zhan
This paper presents a simple scheme for information transmission between two non-directly interactive qubits in an n-qubit system. An example has been realized on a three-qubit nuclear magnetic resonance (NMR) spectrometer quantum computer. The experimental result successfully demonstrates that the feasible measure can also be extended to other quantum logical gates, or other quantum algorithms, where some qubits have no direct interactions in a multi-qubit system.
Biochemistry | 2007
Olga Buczek; Daxiu Wei; Jeffrey J. Babon; Xiaodong Yang; Brian Fiedler; Ping Chen; Doju Yoshikami; Baldomero M. Olivera; Grzegorz Bulaj; Raymond S. Norton
Chinese Science Bulletin | 2004
Daxiu Wei; Xiaodong Yang; Jun Luo; Xianping Sun; Xizhi Zeng; Maili Liu
Physical Review A | 2002
Xiaodong Yang; Daxiu Wei; Jun Luo; Xijia Miao
Applied Magnetic Resonance | 2015
Yan Chang; Daxiu Wei; Steffen J. Glaser; Xiaodong Yang