Experimental open air quantum key distribution with a single photon source

We present a full implementation of a quantum key distribution (QKD) system with a single photon source, operating at night in open air. The single photon source at the heart of the functional and reliable setup relies on the pulsed excitation of a single nitrogen-vacancy color center in diamond nanocrystal. We tested the effect of attenuation on the polarized encoded photons for inferring longer distance performance of our system. For strong attenuation, the use of pure single photon states gives measurable advantage over systems relying on weak attenuated laser pulses. The results are in good agreement with theoretical models developed to assess QKD security

Demonstration of Einstein-Podolsky-Rosen Steering with Enhanced Subchannel Discrimination

Einstein-Podolsky-Rosen (EPR) steering describes a quantum nonlocal phenomenon in which one party can nonlocally affect the other's state through local measurements. It reveals an additional concept of quantum nonlocality, which stands between quantum entanglement and Bell nonlocality. Recently, a quantum information task named as subchannel discrimination (SD) provides a necessary and sufficient characterization of EPR steering. The success probability of SD using steerable states is higher than using any unsteerable states, even when they are entangled. However, the detailed construction of such subchannels and the experimental realization of the corresponding task are still technologically challenging. In this work, we designed a feasible collection of subchannels for a quantum channel and experimentally demonstrated the corresponding SD task where the probabilities of correct discrimination are clearly enhanced by exploiting steerable states. Our results provide a concrete example to operationally demonstrate EPR steering and shine a new light on the potential application of EPR steering.Comment: 16 pages, 8 figures, appendix include

Heat Transfer and Pressure Drop in a Developing Channel Flow with Streamwise Vortices

Experiments to assess the heat transfer and pressure-drop effects of delta-wing vortex generators placed at the entrance of developing channel flows are reported in this study. The experimental geometry simulates common heat exchanger configurations and tests are conducted over a velocity range important to heating, air conditioning and refrigeration. An innovative liquid-crystal thermography technique is used to determine the local and average Nusselt numbers for an isoflux channel wall, and conventional methods are used to determine the Fanning friction factor. Vortex generators with aspect ratios of A = 2 and A = 4 are studied at attack angles of a. = 20?? to 45????. The results indicate that the streamwise vortices generated by a delta wing can enhance local Nusselt numbers by more than 200% in a developing channel flow. Under some conditions, the spatially average Nusselt number nearly doubled for a heat transfer area that was 37 to 63 times the wing area. The Fanning friction factor increased by a few percent to nearly 60%, depending on the Reynolds number.Air Conditioning and Refrigeration Project 4

Security and Privacy for Modern Wireless Communication Systems

The aim of this reprint focuses on the latest protocol research, software/hardware development and implementation, and system architecture design in addressing emerging security and privacy issues for modern wireless communication networks. Relevant topics include, but are not limited to, the following: deep-learning-based security and privacy design; covert communications; information-theoretical foundations for advanced security and privacy techniques; lightweight cryptography for power constrained networks; physical layer key generation; prototypes and testbeds for security and privacy solutions; encryption and decryption algorithm for low-latency constrained networks; security protocols for modern wireless communication networks; network intrusion detection; physical layer design with security consideration; anonymity in data transmission; vulnerabilities in security and privacy in modern wireless communication networks; challenges of security and privacy in node–edge–cloud computation; security and privacy design for low-power wide-area IoT networks; security and privacy design for vehicle networks; security and privacy design for underwater communications networks