Liu Qiu-Yu

The Perturbed Puma Model

The puma model on the basis of the Lorentz and CPT violation may bring an economical interpretation to the conventional neutrinos oscillation and part of the anomalous oscillations. We study the effect of the perturbation to the puma model. In the case of the first-order perturbation which keeps the (23) interchange symmetry, the mixing matrix element Ue3 is always zero. The nonzero mixing matrix element Ue3 is obtained in the second-order perturbation that breaks the (23) interchange symmetry.

State-Vector Space and Canonical Coherent States in Noncommutative Plane

The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously include coordinate-coordinate non-commutativity and momentum-momentum non-commutativity, which lead to noncommutative Fock space. By this we mean that creation and annihilation operators corresponding to different degrees of freedom of the bosons do not commute each other. The main character of the noncommutative Fock space is there are no ordinary number representations because of the non-commutativity between different number operators. However, eigenvectors of several pairs of commuting Hermitian operators are obtained which can also be served as bases in this Fock space. As a simple example, an explicit form of two-dimensional canonical coherent state in this noncommutative Fock space is constructed and its properties are discussed.The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose–Einstein statistics the commutation relations of phase space variables should simultaneously include coordinate-coordinate non-commutativity and momentum-momentum non-commutativity, which leads to a kind of deformed Heisenberg-Weyl algebra. Although there is no ordinary number representation in this state-vector space, several set of orthogonal and complete state-vectors can be derived which are common eigenvectors of corresponding pairs of commuting Hermitian operators. As a simple application of this state-vector space, an explicit form of two-dimensional canonical coherent state is constructed and its properties are discussed.

q-Deformed Entangled States Representations and Some Applications

The q-deformed entangled states are introduced by using deformation quantization methods and new normal ordering of the vacuum projection operator for q-deformed boson oscillator. In similar way, by virtue of the technique of integration within an ordered product (IWOP) of operators, the new completeness and orthogonality relations composed of the bra and ket, which are not mutually Hermitian conjugates are obtained. Furthermore, the property of squeezing operator represented by the q-deformed entangled states is exhibited. Lastly, the nonclassical properties of the q-deformed two-mode squeezed vacuum state are studied.

Flavor State of the Neutrino: Conditions for a Consistent Definition

Similar to Blasone et al. [Phys. Rev. D 72 (2005) 013003] by examining the expectation value of the flavor charge under the normalized flavor state of the neutrino, we demonstrate that the introduction of the flavor state is consistent with the flavor charge only when the conditions, i.e. (A) |p| = 0 (the low energy case), or |p|/mi 1 (the relativistic case) and (B) the flavor state should be defined of the Pontecorvo form |?e? = cos ?|?1? + sin ?|?2? or equivalently except a global phase, are satisfied. The root of the issue lies in the structure of the flavor charge operator. The diagonalization of the flavor charge operator with the integer eigenvalue can be realized through the Bogoliubov-Valatin transformation when condition A is satisfied. The eigenstate of the diagonalized flavor charge is of the Pontecorvo form under condition B.

Solving Solar Neutrino Puzzle via LMA MSW Conversion

We analyze the existed solar neutrino experiment data and show the allowed regions. The result from SNO’s salt phase itself restricts quite a lot the allowed region’s area. Reactor neutrinos play an important role in determining oscillation parameters. KamLAND gives decisive conclusion on the solution to the solar neutrino puzzle, in particular, the spectral distortion in the 766.3 Ty KamLAND data gives another new improvement in the constraint of solar MSW-LMA solutions. We confirm that at 99.73% C.L. the high-LMA solution is excluded. ∗email: qiuyu@ustc.edu.cn 1We analyze the existing solar neutrino experiment data and show the allowed regions. The result from SNOs salt phase itself restricts quite a lot the allowed regions area. Reactor neutrinos play an important role in determining oscillation parameters. KamLAND gives decisive conclusion on the solution to the solar neutrino puzzle, in particular, the spectral distortion in the 766.3 Ty KamLAND data gives another new improvement in the constraint of solar MSW-LMA solutions. We confirm that at 99.73% C.L. the high-LMA solution is excluded.

New equation for deriving pure state density operators by Weyl correspondence and Wigner operator

By virtue of the completeness of Wigner operator and Weyl correspondence we construct a general equation for deriving pure state density operators. Several important examples are considered as the applications of this equation, which shows that our approach is effective and convenient for deducing these entangled state representations.

Solar Neutrino Oscillation Parameters after SNO Phase-III and SAGE Part-III

We analyse the recently published results from solar neutrino experiments SNO Phase-III and SAGE Part-III and show their constraints on solar neutrino oscillation parameters, especially for the mixing angle θ12. Through a global analysis using all existing data from SK, SNO, Ga&Cl radiochemical experiments and long base line reactor experiment KamLAND, we obtain the parameters . We also find that the discrepancy between the KamLAND and solar neutrino results can be reduced by choosing a small non-zero value for the mixing angle θ13.

Precise Measurement of Solar Neutrino Oscillation Parameters from Recent Experiments

We analyse the available data of solar neutrino experiments up to the date May 2008, including SK-I, SK-II, SNO phase-I, SNO phase-II and first-generation Ga and Cl experiments. They show great improvement in constraints on solar neutrino oscillation parameters. Together with the new results from long base line reactor experiment KamLAND, the parameters are precisely determined, with 1σ allowed region in Δm122 = 7.586−0.203+0.212 × 10−5 eV2, tan2θ12 = 0.457−0.067+0.076.

Phenomenology of Friedberg-Lee Texture in Left-Right Symmetric Model

We consider that the Higgs triplet Yukawa coupling takes the Friedberg–Lee texture, and the Higgs doublet Yukawa coupling simply identifies with the diagonal Yukawa coupling of charged lepton in the context of left-right symmetric model. In this scenario, the phenomenology, including effective neutrino masses, mixings, and thermal flavor-dependent leptogenesis and lepton flavor violation decays are studied. We investigate the combined constrain of the parameters in this scenario and test its consistency with present data.

Path Integral Formalism for Nondegenerate Parametric Amplifiers in Entangled State Representation

We establish the path integral formalism for nondegenerate parametric amplifiers in the entangled state representations. Its advantage in obtaining the energy level gap of this system is analyzed.