Chinese Physics 

About: Chinese Physics is an academic journal. The journal publishes majorly in the area(s): Laser & Nonlinear system. It has an ISSN identifier of 1000-3290. It is also open access. Over the lifetime, 2965 publications have been published receiving 24076 citations.

Non-equilibrium extrapolation method for velocity and pressure boundary conditions in the lattice Boltzmann method

Abstract: In this paper, we propose a new approach to implementing boundary conditions in the lattice Boltzmann method (LBM). The basic idea is to decompose the distribution function at the boundary node into its equilibrium and non-equilibrium parts and then to approximate the non-equilibrium part with a first-order extrapolation of the non-equilibrium part of the distribution at the neighbouring fluid node. Schemes for velocity and pressure boundary conditions are constructed based on this method. The resulting schemes are of second-order accuracy. Numerical tests show that the numerical solutions of the LBM together with the present boundary schemes are in excellent agreement with the analytical solutions. Second-order convergence is also verified from the results. It is also found that the numerical stability of the present schemes is much better than that of the original extrapolation schemes proposed by Chen et al. (1996 Phys. Fluids 8 2527).

Controlled quantum teleportation and secure direct communication

Abstract: We present a controlled quantum teleportation protocol. In the protocol, quantum information of an unknown state of a 2-level particle is faithfully transmitted from a sender Alice to a remote receiver Bob via an initially shared triplet of entangled particles under the control of the supervisor Charlie. The distributed entangled particles shared by Alice, Bob and Charlie function as a quantum information channel for faithful transmission. We also propose a controlled and secure direct communication scheme by means of this teleportation. After ensuring the security of the quantum channel, Alice encodes the secret message directly on a sequence of particle states and transmits them to Bob supervised by Charlie using this controlled quantum teleportation. Bob can read out the encoded message directly by the measurement on his qubit. In this scheme, the controlled quantum teleportation transmits Alice's message without revealing any information to a potential eavesdropper. Because there is not a transmission of the qubit carrying the secret message between Alice and Bob in the public channel, it is completely secure for controlled and direct secret communication if perfect quantum channel is used. The special feature of this scheme is that the communication between two sides depends on the agreement of a third side to co-operate.

EMC effect on p-A high energy collisions

Abstract: According to the perturbative-QCD method, we have calculated the P ⊥ distributive cross sections, the Y distributive cross sections of the large-P ⊥ jets and the final-state meson productivities in 800 GeV/c proton-nucleus (Be, C, Al, Cu and Pb) collisions. The A dependence of the cross section at a given P ⊥ is discussed with the consideration of the EMC effect. The dσ/dP ⊥ differential cross sections vs P ⊥ for various pA collisions are consistent with the new data

Quantum secure direct communication with quantum encryption based on pure entangled states

Abstract: This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs (quantum key) shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.

GREAT MAGNETIC ENTROPY CHANGE IN La(Fe, M) 13 (M=Si, Al) WITH Co DOPING

Abstract: Very large magnetic entropy change ?SM, which originates from a fully reversible second-order transition at Curie temperature TC, has been discovered in compounds La(Fe, Si)13, La(Fe, Al)13 and those with Co doping. The maximum change ?SM ? 19 J?kg-1?K-1, achieved in LaFe11.4Si1.6 at 209K upon a 5T magnetic field change, exceeds that of Gd by more than a factor of 2. The TC of the Co-doped compounds shifts to higher temperatures. ?SM still has a considerable large magnitude near room temperature. The phenomena of very large ?SM, convenience of adjustment of TC, and also the superiority of low cost, strongly suggest that the compounds La(Fe, M)13 (M=Si, Al) with Co doping are suitable candidates for magnetic refrigerants at high temperatures.