Estimation of Spin-Spin Interaction by Weak Measurement Scheme

Precisely knowing an interaction Hamiltonian is crucial to realize quantum information tasks, especially to experimentally demonstrate a quantum computer and a quantum memory. We propose a scheme to experimentally evaluate the spin-spin interaction for a two-qubit system by the weak measurement technique initiated by Yakir Aharonov and his colleagues. Furthermore, we numerically confirm our proposed scheme in a specific system of a nitrogen vacancy center in diamond. This means that the weak measurement can also be taken as a concrete example of the quantum process tomography.Comment: 4 pages, 1 table, 2 figures, to appear in Europhysics Letter

A note on entropic force and brane cosmology

Recently Verlinde proposed that gravity is an entropic force caused by information changes when a material body moves away from the holographic screen. In this note we apply this argument to brane cosmology, and show that the cosmological equation can be derived from this holographic scenario.Comment: 5 pages, no figures;references adde

Design method of fabric formed concrete beams reinforced with W-FRP

Flexible moulds as external formwork and a novel robotically fabricated reinforcement, Wound FRP (W-FRP), provide the solution for the manufacture of complex structural concrete components being optimised to minimise material use and further reduce the carbon emissions from constructional industry. However, previous research has shown that the non-prismatic geometries and linear-elastic reinforcement could result in very different structural behaviours from the traditional concrete beams and invalidity of the existing codified design approaches. This research proposes revisions to the empirical equation to calculate the tensile force of inclined flexural reinforcement and a design method to predict the shear capacity of the W-FRP reinforced non-prismatic beams based on Modified Compression Field Theory (MCFT). A full-scale test of fabric formed T beam reinforced with W-FRP was conducted to demonstrate the validity of this new design approach. The research in this paper shows that: 1) the invalidity of the codified design approach could be attributed to the empirical calibration with prismatic beams; 2) geometry of the beam and the W-FRP shear reinforcement ratio are the main factors influence the flexural bar force development and 3) the proposed equation for calculating tensile force of flexural reinforcement could accurately predict the force development. This research provides a practical and valid approach for the future design of non-prismatic beams reinforced with W-FRP and addresses technical challenges in the way to minimising material use in concrete structures

A model of CP Violation from Extra Dimension

We construct a realistic model of CP violation in which CP is broken in the process of dimensional reduction and orbifold compactification from a five dimensional theories with $SU(3)\times SU(3) \times SU(3)$ gauge symmetry. CP violation is a result of the Hosotani type gauge configuration in the higher dimension.Comment: 5 page