Source-independent quantum random number generation

Quantum random number generators can provide genuine randomness by appealing to the fundamental principles of quantum mechanics. In general, a physical generator contains two parts---a randomness source and its readout. The source is essential to the quality of the resulting random numbers; hence, it needs to be carefully calibrated and modeled to achieve information-theoretical provable randomness. However, in practice, the source is a complicated physical system, such as a light source or an atomic ensemble, and any deviations in the real-life implementation from the theoretical model may affect the randomness of the output. To close this gap, we propose a source-independent scheme for quantum random number generation in which output randomness can be certified, even when the source is uncharacterized and untrusted. In our randomness analysis, we make no assumptions about the dimension of the source. For instance, multiphoton emissions are allowed in optical implementations. Our analysis takes into account the finite-key effect with the composable security definition. In the limit of large data size, the length of the input random seed is exponentially small compared to that of the output random bit. In addition, by modifying a quantum key distribution system, we experimentally demonstrate our scheme and achieve a randomness generation rate of over $5\times 10^3$ bit/s.Comment: 11 pages, 7 figure

Unified framework for quantumness -- coherence, discord, and entanglement

From an operational perspective, quantumness characterizes the exotic behavior in a physical process which cannot be explained with Newtonian physics. There are several widely used measures of quantumness, including coherence, discord, and entanglement, each proven to be essential resources in particular situations. There exists evidence of fundamental connections amongst the three measures. However, those quantumnesses are still regarded differently and such connections are yet to be elucidated. Here, we introduce a general framework of defining a unified quantumness with an operational motivation founded on the capability of interferometry. The quantumness appears differently as coherence, discord, and entanglement in different scenarios with local measurement, weak reference frame free measurement, and strong reference frame free measurement, respectively. Our results also elaborate how these three measures are related and how they can be transformed from each other. This framework can be further extended to other scenarios and serves as a universal quantumness measure.Comment: 9 pages, 4 figure

Raman Spectroscopy for Monitoring Strain on Graphene and Oxidation Corrosion on Nuclear Claddings

Raman scattering can explore a material’s structure, composition, and condition. In this chapter, we demonstrate the application of Raman scattering to monitor the change in the physical properties and chemical composition of materials. We provide two examples: (1) the Raman peak profile and shift reveal the strain in graphene induced by nanostructure and (2) the appearance and intensity of the Raman peaks indicate the oxidation corrosion on Zircaloy nuclear fuel cladding. The Raman spectroscopy is capable of providing evident and precise signals for the monitoring tasks. Through this research, we propose Raman spectroscopy to be a sensitive, accurate, and nondestructive tool for monitoring material conditions

Security assessment and key management in a quantum network

Quantum key distribution allows secure key distribution between remote communication parties. In a quantum network, multiple users are connected by quantum links for key distribution and classical links for encrypted data transmission. When the quantum network structure becomes complicated with a large number of users, it is important to investigate network issues, including security, key management, latency, reliability, scalability, and cost. In this work, we utilize the classical network theory and graph theory to establish a framework for a quantum network, addressing two critical issues, security and key management. First, we design a communication scheme with the highest security level that trusts a minimum number of intermediate nodes. Second, when the quantum key is a limited resource, we design key management and data scheduling schemes to optimize the utility of data transmission. Our results can be directly applied to the current metropolitan and free-space quantum network implementations and can potentially be a standard approach for future quantum network designs.Comment: 11 pages, 2 figure

Cloud Point Extraction-HPLC Determination of Polycyclic Aromatic Hydrocarbons Residues in Traditional Chinese Medicinal Herbs

AbstractA method was developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) residues in traditional Chinese medicinal herbs by using cloud point extraction combined with high performance liquid chromatography- fluorescence detection. Non-ionic surfactant Genapol X-080 was used for the cloud point extraction of five PAHs residues. Some important parameters influencing the extraction efficiency, such as the surfactant concentration, ultrasonic-assisted extraction time, liquid to solid ratio, salt concentration as well as the equilibration time and temperature, were investigated in detail. Experimental results showed that good linearity could be obtained in the concentration range of 0.05-20ng/ml for all the five PAHs with correlation coefficients between 0.9989 and 0.9999. Relative standard deviations for five replicate determinations of PAHs were between 4.6-6.6%. The established method has been successfully applied to the determination of PAHs residues in Rehmannia, Radix Isatidis, Rhizoma Coptidis, Root of Auricledleaf Swallowwort and Radix Scutellariae