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Fault-Tolerate Three-Party Quantum Secret Sharing over a Collective-Noise Channel

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Chinese Physics Letters 2011年第2期28卷 35-38页

作者： LI Chun-Yan LI Yan-Song key laboratory for atomic and molecular nanosciences and Department of Physics Tsinghua UniversityBeijing 100084 Tsinghua National laboratory for Information Science and technology Beijing 100084

We present a fault-tolerate three-party quantum secret sharing(QSS)scheme over a collective-noise ***-free subspaces are used to tolerate two noise modes,a collective-dephasing channel and a collective-rotating channel,*** this scheme,the boss uses two physical qubits to construct a logical qubit which acts as a quantum channel to transmit one bit information to her two *** agents can get the information of the private key established by the boss only if they *** boss Alice encodes information with two unitary *** single-photon measurements are required to rebuilt Alice's information and detect the security by the agents Bob and Charlie,not Bell-state ***,Almost all of the photons are used to distribute information,and its success efficiency approaches 100%in theory.

关键词： theory collective quantum

A Comparative Study of Quantum and Classical Deletion

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Communications in Theoretical Physics 2010年第3期53卷 486-488页

作者：沈尧郝亮龙桂鲁 key laboratory for atomic and molecular nanosciences and Department of Physics Tsinghua University Tsinghua National laboratory for Information Science and Technology Tsinghua University

Here in this letter, we study the difference between quantum and classical deletion. We point out that the linear mapping deletion operation used in the impossibility proof for quantum systems applies also to classical system. The general classical deletion operation is a combined operation of measurement and transformation, i.e., first read the state and then transfer the state to the standard blank state. Though both quantum information and classical information can be deleted in an open system, quantum information cannot be recovered while classical information can be recovered.

关键词： quantum deletion classical deletion quantum computing

Measuring-basis-encrypted six-state quantum key distribution scheme

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Progress in Natural Science:Materials International 2006年第1期16卷 84-89页

作者： CHEN Pan1, DENG Fuguo1, WANG Pingxiao1 and LONG Guilu1,2 (key laboratory for Quantum Information and Measurements and Department of Physics, Tsinghua University, Beijing 100084, China 2. key laboratory for atomic and molecular nanosciences, Tsinghua University, Beijing 100084, China) key laboratory for Quantum Information and Measurements Department of Physics Tsinghua University Beijing 100084 China key laboratory for atomic and molecular nanosciences Tsinghua University Beijing 100084 China

A six-state quantum key distribution scheme with measuring-basis encryption technique, which is based on the six-state protocol and the MBE protocol, is proposed. In this modified six-state quantum key distribution protocol, Alice and Bob use a control key to synchronize the use of their measuring-basis so that they always use the same measuring-basis. This modified six-state quantum key distribution protocol retains the advantage of higher security and at the same time has a higher efficiency.

关键词： quantum key distribution measuring-basis encrypted six-state security.

Why Can We Copy Classical Information？

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Chinese Physics Letters 2011年第1期28卷 30-31页

作者： SHEN Yao key laboratory for atomic and molecular nanosciences and Department of Physics Tsinghua University Beijing 100084 Tsinghua National laboratory for Information Science and Technology Tsinghlza University Beijing 100084

It is pointed out that the noneloning theorem in quantum mechanics also holds for unknown state in linear classical physics. The apparent capability of copying of a classical state is essentially the capability of perfect measurement in classical physics. The difference in copying- between quantum and classical physics is the difference in measurement between the two theories. A classical copying process is the combined action of measurement of an unknown state and the preparation of this state onto another system. Hence perfect measurability in classical physics enables the copying of a classical state.

关键词： Physics Measurement

A scheme to implement the Deutsch-Josza algorithm on a superconducting charge-qubit quantum computer

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Progress in Natural Science:Materials International 2006年第6期16卷 594-599页

作者： HUO Wenyi and LONG Guilu (key laboratory for Quantum Information and Measurements, and Department of Physics, Tsinghua University, Beijing 100084, China key laboratory for atomic and molecular nanosciences, Tsinghua University, Beijing 100084, China) key laboratory for Quantum Information and Measurements Department of Physics Tsinghua University Bejjing 100084 China key laboratory for atomic and molecular nanosciences Tsinghua University Bejing 100084 China

We have studied the implementation of the Deutsch-Josza quantum algorithm in a superconducting charge-qubit quantum computer. Different from previous studies, we have used the inductance coupled system of You et al. The detailed pulse sequences have been designed for the four possible functions in a 2-qubit system. The result is generalized to an arbitrary n-qubit system. This scheme will be useful for practical implementation of the algorithm.

关键词： superconducting quantum computer Deutsch-Josza algorithm.

Experimental realization of quantum cryptography communication in free space

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Science China(Physics,Mechanics & Astronomy) 2005年第2期48卷 237-246页

作者： WANG Chuan1, ZHANG Jingfu1, WANG Pingxiao1, DENG Fuguo1, AI Qing1 & LONG Guilu1,2 1. Department of Physics, key laboratory for Quantum Information and Measurements, Tsinghua Univer- sity, Beijing 100084, China 2. Center for atomic and molecular nanosciences, Tsinghua University, Beijing 100084, China Department of Physics Key Laboratory for Quantum Information and Measurements Tsinghua University Beijing China atomic and molecular nanosciences Tsinghua University Beijing China

Utilizing linear optical devices, the principle of B92 quantum key distribution (QKD) protocol is demonstrated in free space with a distance of transmission of 2.2 meters. The faint laser pulses with 650 nm wavelength are used as the single photon sources. The experimental results show that the eavesdropping behavior in the signal transmission can be detected. We also discuss the problems and solutions in using the quantum cryptography communication practically. It is pointed out that one of the approaches to increasing the distance of the quantum communication is to overcome the attenuation of the single photon in transmission. This could not be solved by the use of single photon source, and new quantum communication protocols are needed to solve these problems.

关键词： quantum key distribution, free space, linear optics, faint pulses.

A Theoretical Study of Clusters： Realizing Differences between the Second-Row and the Third-Row Elements

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Chinese Physics Letters 2006年第7期23卷 1757-1760页

作者：许雅歌纪冬申旭阳王晓路李家明 Department of Physics Shanghai Jiao Tong University Shanghai 200030 key laboratory of atomic and molecular nanosciences Department of Physics Tsinghua University Beijing 100084

Based on the characteristics of valence bonds and the first-principle molecular dynamics simulation we present an optimum valence bond scheme to study properties of important critical clusters with limited computational effort. The differences between the second-row and the third-row elements belonging to the same families can be understood by examining electronic structures and geometric structures even for small size clusters.

关键词： molecular-DYNAMICS STABILITY DENSITY MATTER

TiO_2 composite electron transport layers for planar perovskite solar cells by mixed spray pyrolysis with precursor solution incorporating TiO_2 nanoparticles

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Chinese Physics B 2018年第1期27卷 121-126页

作者：田嘉琪李红翠王海月郑博薛叶斌刘喜哲 Institute of atomic and molecular Physics Jilin Provincial Key Laboratory of Applied Atomic and Molecular SpectroscopyJilin University

Perovskite solar cells with planar structure are attractive for their simplified device structure and reduced hysteresis effect. Compared to conventional mesoporous devices, TiO2 porous scaffold layers are removed in planar devices. Then, compact TiO2 electron transport layers take the functions of extracting electrons, transporting electrons, and blocking holes. Therefore, the properties of these compact TiO2 layers are important for the performance of solar cells. In this work, we develop a mixed spray pyrolysis method for producing compact TiO2 layers by incorporating TiO2 nanoparticles with dif- ferent size into the precursor solutions. For the optimized nanoparticle size of 60 nm, a power conversion efficiency of 16.7% is achieved, which is obviously higher than that of devices without incorporated nanoparticles （9.9%）. Further in- vestigation reveals that the incorporation of nanoparticles can remarkably improve the charge extraction and recombination processes.

关键词： perovskite solar cell electron transport layer charge extraction recombination

General Quantum Interference Principle and Duality Computer

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Communications in Theoretical Physics 2006年第5期45卷 825-844页

作者： LONG Gui-Lu key laboratory for Quantum Information and Measurements and Department of Physics Tsinghua University Beijing100084 China key laboratory of atomic and molecular nanosciences Tsinghua University Beijing 100084 China

In this article, we propose a general principle of quantum interference for quantum system, and based on this we propose a new type of computing machine, the duality computer, that may outperform in principle both classical computer and the quantum computer. According to the general principle of quantum interference, the very essence of quantum interference is the interference of the sub-waves of the quantum system itself A quantum system considered here can be any quantum system： a single microscopic particle, a composite quantum system such as an atom or a molecule, or a loose collection of a few quantum objects such as two independent photons. In the duality computer, the wave of the duality computer is split into several sub-waves and they pass through different routes, where different computing gate operations are performed. These sub-waves are then re-combined to interfere to give the computational results. The quantum computer, however, has only used the particle nature of quantum object. In a duality computer, it may be possible to find a marked item from an unsorted database using only a single query, and all NP-complete problems may have polynomial algorithms. Two proof-of-the-principle designs of the duality computer are presented： the giant molecule scheme and the nonlinear quantum optics scheme. We also propose thought experiment to check the related fundamental issues, the measurement efficiency of a partial wave function.

关键词： quantum interference duality computer NP-complete = P