Chinese Physics B

Xie, Ying-Tao; Yang, Li-Xia

doi: 10.1088/1674-1056/20/6/060201pmid: N/A

A novel periodic boundary condition (PBC), that is the constant transverse wavenumber (CTW) method, is introduced to solve the time delay in the transverse plane with oblique incidence. Based on the novel PBC, the FDTD/PBC algorithm is proposed to study periodic structure consisting of plasma and vacuum. Then the reflection coefficient for the plasma slab from the FDTD/PBC algorithm is compared with the analytic results to show the validity of our technique. Finally, the reflection coefficients for the plasma photonic crystals are calculated using the FDTD/PBC algorithm to study the variation of bandgap characteristics with the incident angle and the plasma parameters. Thus it has provided the guiding sense for the actual manufacturing plasma photonic crystal.

Xiang, Yang

doi: 10.1088/1674-1056/20/6/060301pmid: N/A

We give an analytic quantitative relation between Hardy's non-locality and Bell operator. We find that Hardy's non-locality is a sufficient condition for the violation of Bell inequality, the upper bound of Hardy's non-locality allowed by information causality just corresponds to Tsirelson bound of Bell inequality and the upper bound of Hardy's non-locality allowed by the principle of no-signaling just corresponds to the algebraic maximum of Bell operator. Then we study the Cabello's argument of Hardy's non-locality (a generalization of Hardy's argument) and find a similar relation between it and violation of Bell inequality. Finally, we give a simple derivation of the bound of Hardy's non-locality under the constraint of information causality with the aid of the above derived relation between Hardy's non-locality and Bell operator.

Yang, Rong-Can; Li, Gang; Li, Jie; Zhang, Tian-Cai

doi: 10.1088/1674-1056/20/6/060302pmid: N/A

A general scheme of generating N00N states of virtually-excited 2N atoms is proposed. The two cavities are fibre-connected with N atoms in each cavity. Although we focus on the case of N = 2, the system can be extended to a few atoms with N > 2. It is found that all 2N atoms can be entangled in the form of N00N states if the atoms in the first cavity are initially in the excited states and atoms in the second cavity are all in the ground states. The feasibility of the scheme is carefully discussed, it shows that the N00N state with a few atoms can be generated with good fidelity and the scheme is feasible in experiment.

Xie, Chuan-Mei; Fan, Hong-Yi

doi: 10.1088/1674-1056/20/6/060303pmid: N/A

According to FanHu's formalism (Fan Hong-Yi and Hu Li-Yun 2009 Opt. Commun. 282 3734) that the tomogram of quantum states can be considered as the module-square of the state wave function in the intermediate coordinatemomentum representation which is just the eigenvector of the Fresnel quadrature phase, we derive a new theorem for calculating quantum tomogram of density operator, i.e., the tomogram of a density operator is equal to the marginal integration of the classical Weyl correspondence function of FF, where F is the Fresnel operator. Applications of this theorem to evaluating the tomogram of optical chaotic field and squeezed chaotic optical field are presented.

Ding, Bang-Fu; Wang, Xiao-Yun; Tang, Yan-Fang; Mi, Xian-Wu; Zhao, He-Ping

doi: 10.1088/1674-1056/20/6/060304pmid: N/A

We present a non-Markovian master equation for a qubit interacting with a general reservoir, which is derived according to the NakajimaZwanzig and the time convolutionless projection operator technique. The non-Markovian solutions and Markovian solution of dynamical decay of a qubit are compared. The results indicate the validity of non-Markovian approach in different coupling regimes and also show that the Markovian master equation may not precisely describe the dynamics of an open quantum system in some situation. The non-Markovian solutions may be effective for many qubits independently interacting with the heated reservoirs.

Yang, Rong-Guo; Sun, Heng-Xin; Zhang, Jun-Xiang; Gao, Jiang-Rui

doi: 10.1088/1674-1056/20/6/060305pmid: N/A

Spatial quantum optics and quantum information based on the high order transverse mode are of importance for the super-resolution measurement beyond the quantum noise level. We demonstrated experimentally the transverse plane TEM01 HermiteGauss quantum squeezing. The squeezed TEM01 mode is generated in a degenerate optical parametric amplifier with the nonlinear crystal of periodically poled KTiOPO4. The level of 2.2-dB squeezing is measured using a spatial balance homodyne detection system.

Wu, Xi; Chen, Zhi-Hua; Zhang, Yong; Chen, Yue-Hua; Ye, Ming-Yong; Lin, Xiu-Min

doi: 10.1088/1674-1056/20/6/060306pmid: N/A

Schemes are presented for realizing quantum controlled phase gate and preparing an N-qubit W-like state, which are based on the large-detuned interaction among three-state atoms, dual-mode cavity and a classical pulse. In particular, a class of W states that can be used for perfect teleportation and superdense coding is generated by only one step. Compared with the previous schemes, cavity decay is largely suppressed because the cavity is only virtually excited and always in the vacuum state and the atomic spontaneous emission is strongly restrained due to a large atomfield detuning.

Hao, Ya-Jiang

doi: 10.1088/1674-1056/20/6/060307pmid: N/A

This paper investigates the ground-state properties of the mixture composed of the strongly interacting TonksGirardeau gas and spin polarized Fermi gas confined in one-dimensional harmonic traps, where the interaction between the Bose atoms and Fermi atoms is tunable. With a generalized BoseFermi transformation the mixture is mapped into a two-component Fermi gas. The homogeneous Fermi gas is exactly solvable by the Bethe-ansatz method and the ground state energy density can be obtained. Combining the ground-state energy function of the homogeneous system with local density approximation it obtains the ground-state density distributions of inhomogeneous mixture. It is shown that with the increase in bosonfermion interaction, the system exhibits composite-fermionization crossover.

Hua, Wei; Li, Bin; Liu, Xue-Shen

doi: 10.1088/1674-1056/20/6/060308pmid: N/A

The tunneling effect of BoseEinstein condensate (BEC) in a harmonic trap with a Gaussian energy barrier is studied in this paper. The initial condensate evolves into two separate moving condensates after the tunneling time under certain conditions. The interference pattern between the two moving condensates is given as a comparison and as a further demonstration of the existence of the global phase.

Zhang, Jin-Ping; Cheng, Xin-Lu; Zhang, Hong; Yang, Xiang-Dong

doi: 10.1088/1674-1056/20/6/060401pmid: N/A

Three low-lying electronic states (X1+, a3+, and A1) of NO+ ion are studied using the complete active space self-consistent-field (CASSCF) method followed by highly accurate valence internally contracted multi-reference configuration interaction (MRCI) approach in combination of the correlation-consistent sextuple basis set augmented with diffuse functions, aug-cc-pV6Z. The potential energy curves (PECs) of the NO+(X1+, a3+, A1) are calculated. Based on the PECs, the spectroscopic parameters Re, De, e, ee, e, Be, and D0 are reproduced, which are in excellent agreement with the available measurements. By numerically solving the radial Schrödinger equation of nuclear motion using the Numerov method, the first 20 vibrational levels, inertial rotation and centrifugal distortion constants of NO+(X1+, a3+, A1) ion are derived when the rotational quantum number J is equal to zero (J = 0) for the first time, which accord well with the available measurements. Finally, the analytical potential energy functions of these states are fitted, which are used to accurately derive the first 20 classical turning points when J = 0. These results are compared in detail with those of previous investigations reported in the literature.