Concentration for unknown atomic entangled states via cavity decay

We present a physical scheme for entanglement concentration of unknown atomic entangled states via cavity decay. In the scheme, the atomic state is used as stationary qubit and photonic state as flying qubit, and a close maximally entangled state can be obtained from pairs of partially entangled states probabilistically.Comment: Three pages, Two figure

Top quark pair production at small transverse momentum in hadronic collisions

We investigate the transverse momentum resummation for top quark pair production at hadron colliders using the soft-collinear effective theory and the heavy-quark effective theory. We derive the factorization formula for $t\bar{t}$ production at small pair transverse momentum, and show in detail the procedure for calculating the key ingredient of the factorization formula: the next-to-leading order soft functions. We compare our numerical results with experimental data and find that they are consistent within theoretical and experimental uncertainties. To verify the correctness of our resummation formula, we expand it to the next-to-leading order and the next-to-next-to-leading order, and compare those expressions with the exact fixed-order results numerically. Finally, using the results of transverse momentum resummation, we discuss the transverse-momentum-dependent forward-backward asymmetry at the Tevatron.Comment: 39 pages, 7 figures, 1 table; final version in PR

Throughput Maximization for UAV-Aided Backscatter Communication Networks

This paper investigates unmanned aerial vehicle (UAV)-aided backscatter communication (BackCom) networks, where the UAV is leveraged to help the backscatter device (BD) forward signals to the receiver. Based on the presence or absence of a direct link between BD and receiver, two protocols, namely transmit-backscatter (TB) protocol and transmit-backscatter-relay (TBR) protocol, are proposed to utilize the UAV to assist the BD. In particular, we formulate the system throughput maximization problems for the two protocols by jointly optimizing the time allocation, reflection coefficient and UAV trajectory. Different static/dynamic circuit power consumption models for the two protocols are analyzed. The resulting optimization problems are shown to be non-convex, which are challenging to solve. We first consider the dynamic circuit power consumption model, and decompose the original problems into three sub-problems, namely time allocation optimization with fixed UAV trajectory and reflection coefficient, reflection coefficient optimization with fixed UAV trajectory and time allocation, and UAV trajectory optimization with fixed reflection coefficient and time allocation. Then, an efficient iterative algorithm is proposed for both protocols by leveraging the block coordinate descent method and successive convex approximation (SCA) techniques. In addition, for the static circuit power consumption model, we obtain the optimal time allocation with a given reflection coefficient and UAV trajectory and the optimal reflection coefficient with low computational complexity by using the Lagrangian dual method. Simulation results show that the proposed protocols are able to achieve significant throughput gains over the compared benchmarks

A voting scheme with post-quantum security based on physical laws

Traditional cryptography is under huge threat along of the evolution of quantum information and computing. In this paper, we propose a new post-quantum voting scheme based on physical laws by using encrypted no-key protocol to transmit message in the channel, which ensures the post-quantum security. Unlike lattice-based and multivariate-based electronic voting schemes, whose security is based on the computational problems assumption that has not been solved by effective quantum algorithms until now, the security of the voting scheme based on the physical laws is depended on inherent limitations of quantum computers and not influenced by the evolution of new quantum algorithms. In detail, we also rigorously demonstrate that the scheme achieves the post-quantum security and all properties necessary for voting scheme such as the completeness, robustness, privacy, eligibility, unreusability, fairness, and verifiability.Comment: 23pages,1figure,5table

Decoy's Operational Jamming Effect

The number of decoys deployed is very important for the operational effect in practical waractions, and the more number of decoys deployed, the better is the jamming effect. However,in the development of decoys, the cost-benefit factor is most important. So it is important tostudy the problem of decoy™s cost-effectiveness. In this paper, a mathematical model has beenestablished to study the problem of the cost-effectiveness of decoys