117201929
Possible modifications of the gravitational deflection of light
We investigate possible modifications on the gravitational deflection of light. Two forms of deformation of the Schwarzschild spacetime are proposed. The first ansatz is a given Finslerian line element; it could be regarded as a weak quantum gravity effect on the Schwarzschild spacetime. Starting from this ansatz, we deduce the deflection angle of the light ray which passes a weak gravitational source. The second ansatz could be regarded as a quantum vacuum effect on the Schwarzschild spacetime. The deflection angle of the light ray which passes a weak gravitational source is deduced in this Riemannian spacetime. This vacuum effect may distinguish the mixed light rays in the absence of gravitational source by a "spectroscope" (the gravitational source). The solutions of the gravitational field equation in this Riemannian spacetime imply this issue.
2525683
Two particle states in an asymmetric box
The exact two-particle energy eigenstates in an asymmetric rectangular box with periodic boundary conditions in all three directions are studied. Their relation with the elastic scattering phases of the two particles in the continuum are obtained. These results can be viewed as a generalization of the corresponding formulae in a cubic box obtained by Luscher before. In particular, the s-wave scattering length is related to the energy shift in the finite box. Possible applications of these formulae are also discussed.
14104948
Two particle states in an asymmetric box and the elastic scattering phases
The exact two-particle energy eigenstates in a generic asymmetric rectangular box with periodic boundary conditions in all three directions are studied. Their relations with the elastic scattering phases of the two particles in the continuum are obtained for both ${D}_{4}$ and ${D}_{2}$ symmetries. These results can be viewed as a generalization of the corresponding formulas in a cubic box obtained by L\"uscher before. In particular, the s-wave scattering length is related to the energy shift in the finite box. Possible applications of these formulas are also discussed.
118130623
Quantum resonance scheme to measure the gravitational constant G
14722253
STATIC QUARK POTENTIAL AND THE RENORMALIZED ANISOTROPY ON TADPOLE IMPROVED ANISOTROPIC LATTICES
Static quark potential is studied using a tadpole improved gauge lattice action. The scale is set using the potential for a wide range of bare parameters. The renormalized anisotropy of the lattice is also measured.
14726570
Massive domain wall fermions on four-dimensional anisotropic lattices
We formulate the massive domain wall fermions on anisotropic lattices. For the massive domain wall fermion, we find that the dispersion relation assumes the usual form in the low momentum region when the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. For light domain wall fermions, we verified that the chiral mode is stable against quantum fluctuations on anisotropic lattices. This calculation serves as a guidance for the tuning of the parameters in the quark action in future numerical simulations.
1941882
Reexamining charmless B ---> PV decays in QCD factorization approach
Using the QCD factorization approach, we reexamine the two-body hadronic charmless $B$-meson decays to final states involving a pseudoscalar~($P$) and a vector~($V$) meson, with inclusion of the penguin contractions of spectator-scattering amplitudes induced by the $b\to D g^\ast g^\ast$~(where $D=d$ or $s$, and $g^\ast$ denotes an off-shell gluon) transitions, which are of order $\alpha_s^2$. Their impacts on the CP-averaged branching ratios and CP-violating asymmetries are examined. We find that these higher order penguin contraction contributions have significant impacts on some specific decay modes. Since $B\to \pi K^{\ast}$, $K \rho$ decays involve the same electro-weak physics as $B\to \pi K$ puzzles, we present a detailed analysis of these decays and find that the five R-ratios for $B\to \pi K^{\ast}$, $K \rho$ system are in agreement with experimental data except for $R(\pi K^*)$. Generally, these new contributions are found to be important for penguin-dominated $B\to PV$ decays.
118721470
On the SO(10) instanton
A class of instantons in a four-dimensional Euclidean SO(10) model of grand unification is discussed. These solutions in the classical limit have nonzero Lagrangian density at only one single point. These instantons can generate baryon-number violation processes with rates which could be observable in the not too distant future.
117323209
Search for GRB counterparts using the ARGO‐YBJ experiment in shower mode
In this paper, the effective area of the ARGO‐YBJ experiment to detect the gamma rays with energy range from 10 GeV to 1 TeV for different incident zenith angles (0,10,20,30,40 degrees) is given respectively. The optimal event selections to search for GRB counterparts with different cutoff energy models (Ecut = 100 GeV and 1 TeV) are studied. Using these selections and their corresponding angular resolutions the searches are done within two hours around the GRB trigger time via different time windows. Finally, the result for the 20 GRBs in the field of view of ARGO between July 2006 and July 2008 is presented, and the fluence upper limit for each GRB is set at 99% confidence level.
119191019
The effects of a family non-universal Z-prime boson on B--->pipi decays
Motivated by the measured large branching ratio of (the so-called ππ puzzle), we investigate the effects of a family nonuniversal Z′ model on the tree-dominated B → ππ decays. We find that the Z′ coupling parameter with a nontrivial new weak phase , which is relevant to the Z′ contributions to the QCD penguin sector △C5, is needed to reconcile the observed discrepancy. Combined with the recent fitting results from B → πK, πK* and ρK decays, the Z′ parameter spaces are severely reduced but still not excluded entirely, implying that both the "ππ" and "πK" puzzles could be accommodated simultaneously within such a family nonuniversal Z′ model.
118637791
Topological orbital ladders
Synthetic quantum orbital materials, such as the recent double-well optical lattices loaded with s and p orbital atoms [1, 2], open an avenue to exploit symmetries beyond natural crystals. Exotic superfluid states were reported for bosons. Here, we unveil a topological phase of interacting fermions on a two-leg ladder of unequal parity orbitals, derived from the experimentally realized double-well lattices by dimension reduction. Z2 topological invariant originates simply from the staggered phases of sp-orbital quantum tunneling, requiring none of the previously known mechanisms such as spin-orbit coupling or artificial gauge field. Another unique feature is that upon crossing over to two dimensions with coupled ladders, the edge modes from each ladder form a parity-protected flat band at zero energy, opening the route to strongly correlated states controlled by interactions. Experimental signatures are found in density correlations and phase transitions to trivial band and Mott insulators. The uneven double-well potential formed by laser light has been developed into a powerful tool for quantum gases by numerous groups [1–6]. For instance, controls of atoms on the sand p-orbitals of the checkerboard [1] and hexagonal [6] optical lattices have been demonstrated, and correlation between these orbitals tends to give exotic quantum states [6, 7]. Motivated by these developments, we consider a lattice of uneven double-wells where fermionic atoms are loaded up to the sand porbital levels of the shallow and deep wells respectively, as shown in Fig. 1. The spatial symmetry of the orbital wave function dictates the complex hopping amplitudes between nearby sites. Under certain circumstances, as for the uneven double wells, the orbital hopping pattern is sufficient for producing topologically nontrivial band structures [8]. We will first focus on a one-dimensional ladder system illustrated in Fig. 1b and 1c. This corresponds to the quasi-one dimensional limit of a standard double-well optical lattice, with the optical potential given by