33,362 research outputs found
Charmless Non-Leptonic B Decays and R-parity Violating Supersymmetry
We examine the charmless hadronic B decay modes in the context of R-parity
violating (\rpv) supersymmetry. We try to explain the large branching ratio
(compared to the Standard Model (SM) prediction) of the decay . There exist data for other observed modes and among
these modes, the decay is also found to be large
compared to the SM prediction. We investigate all these modes and find that
only two pairs of \rpv coupling can satisfy the requirements without
affecting the other B\ra PP and B\ra VP decay modes barring the decay
B\ra\phi K. From this analysis, we determine the preferred values of the
\rpv couplings and the effective number of color . We also calculate the
CP asymmetry for the observed decay modes affected by these new couplings.Comment: 14 pages, 7 figures; revtex; version published in Phys. Lett.
Hadronic B Decays to Charmless VT Final States
Charmless hadronic decays of B mesons to a vector meson (V) and a tensor
meson (T) are analyzed in the frameworks of both flavor SU(3) symmetry and
generalized factorization. We also make comments on B decays to two tensor
mesons in the final states. Certain ways to test validity of the generalized
factorization are proposed, using decays. We calculate the branching
ratios and CP asymmetries using the full effective Hamiltonian including all
the penguin operators and the form factors obtained in the non-relativistic
quark model of Isgur, Scora, Grinstein and Wise.Comment: 27 pages, no figures, LaTe
Effects of uncertainties and errors on Lyapunov control
Lyapunov control (open-loop) is often confronted with uncertainties and
errors in practical applications. In this paper, we analyze the robustness of
Lyapunov control against the uncertainties and errors in quantum control
systems. The analysis is carried out through examinations of uncertainties and
errors, calculations of the control fidelity under influences of the
certainties and errors, as well as discussions on the caused effects. Two
examples, a closed control system and an open control system, are presented to
illustrate the general formulism.Comment: 4 pages, 5 figure
Observable estimation of entanglement of formation and quantum discord for bipartite mixed quantum states
We present observable lower and upper bounds for the entanglement of
formation (EOF) and quantum discord (QD), which facilitates estimates of EOF
and QD for arbitrary experimental unknown states in finite-dimensional
bipartite systems. These bounds can be easily obtained by a few experimental
measurements on a twofold copy of the mixed states.
Based on our results, we use the experimental measurement data of the real
experiment given by Schmid \textit{et al.} [Phys. Rev. Lett. \textbf{101},
260505 (2008)] to obtain the lower and upper bounds of EOF and QD for the
experimental unknown state.Comment: 8 pages, 5 figure
Mitigating smart card fault injection with link-time code rewriting: a feasibility study
We present a feasibility study to protect smart card software against fault-injection attacks by means of binary code rewriting. We implemented a range of protection techniques in a link-time rewriter and evaluate and discuss the obtained coverage, the associated overhead and engineering effort, as well as its practical usability
A Labelling Scheme for Higher Dimensional Simplex Equations
We present a succinct way of obtaining all possible higher dimensional
generalization of Quantum Yang-Baxter Equation (QYBE). Using the scheme, we
could generate the two popular three-simplex equations, namely: Zamolodchikov's
tetrahedron equation (ZTE) and Frenkel and Moore equation (FME).Comment: To appear as a Letter to the Editor in J. Phys. A:Math and Ge
Einstein Manifolds As Yang-Mills Instantons
It is well-known that Einstein gravity can be formulated as a gauge theory of
Lorentz group where spin connections play a role of gauge fields and Riemann
curvature tensors correspond to their field strengths. One can then pose an
interesting question: What is the Einstein equations from the gauge theory
point of view? Or equivalently, what is the gauge theory object corresponding
to Einstein manifolds? We show that the Einstein equations in four dimensions
are precisely self-duality equations in Yang-Mills gauge theory and so Einstein
manifolds correspond to Yang-Mills instantons in SO(4) = SU(2)_L x SU(2)_R
gauge theory. Specifically, we prove that any Einstein manifold with or without
a cosmological constant always arises as the sum of SU(2)_L instantons and
SU(2)_R anti-instantons. This result explains why an Einstein manifold must be
stable because two kinds of instantons belong to different gauge groups,
instantons in SU(2)_L and anti-instantons in SU(2)_R, and so they cannot decay
into a vacuum. We further illuminate the stability of Einstein manifolds by
showing that they carry nontrivial topological invariants.Comment: v4; 17 pages, published version in Mod. Phys. Lett.
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