36920558
Determination of the Newtonian gravitational constant G with time-of-swing method.
We present a new value of the Newtonian gravitational constant G by using the time-of-swing method. Several improvements greatly reduce the uncertainties: (1) measuring the anelasticity of the fiber directly; (2) using spherical source masses minimizes the effects of density inhomogeneity and eccentricities; (3) using a quartz block pendulum simplifies its vibration modes and minimizes the uncertainty of inertial moment; (4) setting the pendulum and source masses both in a vacuum chamber reduces the error of measuring the relative positions. By two individual experiments, we obtain G = 6.673 49(18) x 10;{-11} m;{3} kg;{-1} s;{-2} with a standard uncertainty of about 2.6 parts in 10;{5}.
117476305
High-performance controllable ambipolar infrared phototransistors based on graphene-quantum dot hybrid
The field effect transistors (FETs) exhibited ultrahigh responsivity (107 A/W) to infrared light with great improvement of mobility in graphene / PbS quantum dot (QD) hybrid. These reported transistors are either unipolar or depletion mode devices. In this paper, we presented and fabricated conveniently-controlled grapheme / PbS QD hybrid FETs. Through the investigation on electric and optoelectronic properties, the ambipolar FETs (normally OFF) can be switched ON by raising gate voltage (VG) up to 3.7 V and -0.8 V in the first and third quadrants. Near these thresholds (VT) each carrier species shows comparable mobility (~ 300 cm2V-1s-1). Photo-responsivity reach ~ 107 A/W near each threshold and it will linearly increases with (VG-VT). These hybrid FETs become strongly competitive candidates for devices in flexible integrated circuits with low cost, large area, low-energy consumption and high performances.
18567161
Finite-dimensional representations of quantum affine algebras
We give a practical method for the construction of finite-dimensional representations of Uq(G), where G is a non-twisted affine Kac-Moody algebra with no derivation and zero central charge. It is well known that the finite-dimensional representations of a quantum group Uq(G) at generic q are simply deformations of the corresponding irreps of the classical Lie algebra G. This is, however, no longer true when one goes over to an affine Kac-Moody algebra G and its q-deformation Uq(G). In most cases it is necessary to take the direct sum of several irreducible Uq(G)-modules to form an irreducible Uq(G)-module which then becomes reducible at q=1. We illustrate our technique by working out explicit examples for G=C2 and G=G2. These finite-dimensional modules may, for example, determine the multiplet structure of quantum solitons in affine Toda theory.
119113547
Petrov type I spacetime and dual relativistic fluids
The Petrov type I condition for the solutions of vacuum Einstein equations in both of the nonrelativistic and relativistic hydrodynamic expansions is checked. We show that it holds up to the third order of the nonrelativistic hydrodynamic expansion parameter, but it is violated at the fourth order even if we choose a general frame. On the other hand, it is found that the condition holds at least up to the second order of the derivative expansion parameter. Turn the logic around, through imposing the Petrov type I condition and Hamiltonian constraint on a finite cutoff surface, we show that the stress tensor of the relativistic fluid can be recovered with correct first order and second order transport coefficients dual to the solutions of vacuum Einstein equations.
19788205
CP-violating phenomenology of flavor conserving two Higgs doublet models
We analyze the constraints on CP-violating, flavor conserving two Higgs doublet models implied by measurements of Higgs boson properties at the Large Hadron Collider (LHC) and by the nonobservation of permanent electric dipole moments (EDMs) of molecules, atoms, and neutrons. We find that the LHC and EDM constraints are largely complementary, with the LHC studies constraining the mixing between the neutral CP-even states and the EDMs probing the effect of mixing between the CP-even and CP-odd scalars. Presently, the most stringent constraints are implied by the nonobservation of the ThO molecule EDM signal. Future improvements in the sensitivity of neutron and diamagnetic atom EDM searches could yield competitive or even more severe constraints. We analyze the quantitative impact of hadronic and nuclear theory uncertainties on the interpretation of the latter systems and conclude that these uncertainties cloud the impact of projected improvements in the corresponding experimental sensitivities.
119214826
Hepta-cuts of two-loop scattering amplitudes
A bstractWe present a method for the computation of hepta-cuts of two loop scattering amplitudes. Four dimensional unitarity cuts are used to factorise the integrand onto the product of six tree-level amplitudes evaluated at complex momentum values. Using Gram matrix constraints we derive a general parameterisation of the integrand which can be computed using polynomial fitting techniques. The resulting expression is further reduced to master integrals using conventional integration by parts methods. We consider both planar and non-planar topologies for 2 → 2 scattering processes and apply the method to compute hepta-cut contributions to gluon-gluon scattering in Yang-Mills theory with adjoint fermions and scalars.
119129530
Exact polynomial solutions of second order differential equations and their applications
We find all polynomials Z(z) such that the differential equation where X(z), Y(z), Z(z) are polynomials of degree at most 4, 3, 2, respectively, has polynomial solutions S(z) = ?ni = 1(z ? zi) of degree n with distinct roots zi. We derive a set of n algebraic equations which determine these roots. We also find all polynomials Z(z) which give polynomial solutions to the differential equation when the coefficients of X(z) and Y(z) are algebraically dependent. As applications to our general results, we obtain the exact (closed-form) solutions of the Schr?dinger-type differential equations describing: (1) two Coulombically repelling electrons on a sphere; (2) Schr?dinger equation from the kink stability analysis of ?6-type field theory; (3) static perturbations for the non-extremal Reissner?Nordstr?m solution; (4) planar Dirac electron in Coulomb and magnetic fields; and (5) O(N) invariant decatic anharmonic oscillator.