Asymptotic SER and Outage Probability of MIMO MRC in Correlated Fading

This letter derives the asymptotic symbol error rate (SER) and outage probability of multiple-input multiple-output (MIMO) maximum ratio combining (MRC) systems. We consider Rayleigh fading channels with both transmit and receive spatial correlation. Our results are based on new asymptotic expressions which we derive for the p.d.f. and c.d.f. of the maximum eigenvalue of positive-definite quadratic forms in complex Gaussian matrices. We prove that spatial correlation does not affect the diversity order, but that it reduces the array gain and hence increases the SER in the high SNR regime.Comment: 10 pages, 2 figures, to appear in IEEE Signal Processing Letter

Current experimental constraints on NMSSM with large lambda

The next-to-minimal supersymmetric model (NMSSM) with a large lambda (the mixing parameter between the singlet and doublet Higgs fields) is well motivated since it can significantly push up the upper bound on the SM-like Higgs boson mass to solve the little hierarchy problem. In this work we examine the current experimental constraints on the NMSSM with a large lambda, which include the direct search for Higgs boson and sparticles at colliders, the indirect constraints from precision electroweak measurements, the cosmic dark matter relic density, the muon anomalous magnetic moment, as well as the stability of the Higgs potential. We find that, with the increase of lambda, parameters like tan-beta, M_A, mu and M_2 are becoming more stringently constrained. It turns out that the maximal reach of lambda is limited by the muon anomalous magnetic moment, and for smuon masses of 200 GeV (500 GeV) the parameter space with lambda > 1.5 (0.6) is excluded.Comment: Version in PRD (figs and discussions added

Thermodynamics of lattice QCD with 2 flavours of colour-sextet quarks: A model of walking/conformal Technicolor

QCD with two flavours of massless colour-sextet quarks is considered as a model for conformal/walking Technicolor. If this theory possess an infrared fixed point, as indicated by 2-loop perturbation theory, it is a conformal(unparticle) field theory. If, on the other hand, a chiral condensate forms on the weak-coupling side of this would-be fixed point, the theory remains confining. The only difference between such a theory and regular QCD is that there is a range of momentum scales over which the coupling constant runs very slowly (walks). In this first analysis, we simulate the lattice version of QCD with two flavours of staggered quarks at finite temperatures on lattices of temporal extent $N_t=4$ and 6. The deconfinement and chiral-symmetry restoration couplings give us a measure of the scales associated with confinement and chiral-symmetry breaking. We find that, in contrast to what is seen with fundamental quarks, these transition couplings are very different. $\beta=6/g^2$ for each of these transitions increases significantly from $N_t=4$ and $N_t=6$ as expected for the finite temperature transitions of an asymptotically-free theory. This suggests a walking rather than a conformal behaviour, in contrast to what is observed with Wilson quarks. In contrast to what is found for fundamental quarks, the deconfined phase exhibits states in which the Polyakov loop is oriented in the directions of all three cube roots of unity. At very weak coupling the states with complex Polyakov loops undergo a transition to a state with a real, negative Polyakov loop.Comment: 21 pages, 9 figures, Revtex with postscript figures. One extra reference was added; text is unchanged. Corrected typographical erro