Microwave-induced resistance oscillations in a back-gated GaAs quantum well

We performed effective mass measurements employing microwave-induced resistance oscillation in a tunable-density GaAs/AlGaAs quantum well. Our main result is a clear observation of an effective mass increase with decreasing density, in general agreement with earlier studies which investigated the density dependence of the effective mass employing Shubnikov- de Haas oscillations. This finding provides further evidence that microwave-induced resistance oscillations are sensitive to electron-electron interactions and offer a convenient and accurate way to obtain the effective mass.Comment: 4 pages, 4 figure

Investigating the dynamics of, and interactions between, Shanghai office submarkets

The Shanghai office market has developed rapidly over the past two decades. As a consequence of this development, two, apparently distinct, office submarkets, Puxi and Pudong have developed in central Shanghai. This raises the issue as to whether the Shanghai office market can be viewed as a homogeneous entity or whether there is imperfect substitutability across office locations within the city. The latter case raises the possibility of the existence of office submarkets. In this paper, we examine intra-metropolitan rental dynamics in the Puxi and Pudong submarkets, identifying any interrelationships between these markets, and consider whether they form distinct office submarkets. We find no interaction between the two submarkets. Further, we find no evidence of lead-lag relationships between the two submarkets. Finally, when we test for convergence in rental performance between the two submarkets, the tests reveal that we can reject the null of no convergence

An econometric analysis of Shanghai office rents

The modern commercial office market in Shanghai emerged with China’s economic reform and open door policy in the 1980s and grew rapidly at the beginning of 1990s,with increasing demand for office space from foreign and domestic occupiers. Though total real estate investment is skewed towards residential property, office investment has grown by 23% per annual in terms of value and by 24% per annum in terms of completed floor space from 1995 to 2007. The Shanghai office market is of importance for a number of reasons. First, it is one of the largest office markets in China in terms of square footage and in investment terms. Second, the office market is one of most established ones in China and attracts most attention from policy makers, investors, practitioners and academia. However, so far there is little empirical research on the Shanghai office market. This paper will use econometric modelling techniques to investigate office rent determination of the CBD in the central Puxi area, Shanghai, over the period 1991 –2007. Using a reduced form modelling specification in an error correction framework based on demand and supply interactions, GDP and office stock are found to significantly affect office rental performance in the Shanghai market in the long run. The model also shows that the office market adjusts to equilibrium. This model is then extended to test the impact of foreign direct investment, real interest rates, and vacancy rates on rental determination

Constraints on f(RijklRijkl)f(R_{ijkl}R^{ijkl}) gravity: An evidence against the covariant resolution of the Pioneer anomaly

We consider corrections in the form of $\Delta L(R_{ijkl}R^{ijkl})$ to the Einstein-Hilbert Lagrangian. Then we compute the corrections to the Schwarszchild geometry due to the inclusion of this general term to the Lagrangian. We show that $\Delta L_3=\alpha_{{1/3}}(R_{ijkl}R^{ijkl})^{{1/3}}$ gives rise to a constant anomalous acceleration for objects orbiting the Sun onward the Sun. This leads to the conclusion that $\alpha_{{1/3}}=(13.91\pm 2.11) \times 10^{-26}(\frac{1}{\text{meters}})^{{2/3}}$ would have covariantly resolved the Pioneer anomaly if this value of $\alpha_{{1/3}}$ had not contradicted other observations. We notice that the experimental bounds on $\Delta L_3$ grows stronger in case we examine the deformation of the space-time geometry around objects lighter than the Sun. We therefore use the high precision measurements around the Earth (LAGEOS and LLR) and obtain a very strong constraint on the corrections in the form of $\Delta L(R_{ijkl}R^{ijkl})$ and in particular $\Delta L=\alpha_n(R_{ijkl}R^{ijkl})^n$. This bound requires $\alpha_{{1/3}}\leq6.12\times 10^{-29}(\frac{1}{\text{meters}})^{{2/3}}$. Therefore it refutes the covariant resolution of the Pioneer anomaly.Comment: ...v5: references added, new discussions adde

Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering

A practical scheme for the demonstration of perfect one-sided device-independent quantum secret sharing is proposed. The scheme involves a three-mode optomechanical system in which a pair of independent cavity modes is driven by short laser pulses and interact with a movable mirror. We demonstrate that by tuning the laser frequency to the blue (anti-Stokes) sideband of the average frequency of the cavity modes, the modes become mutually coherent and then may collectively steer the mirror mode to a perfect Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally feasible, it is robust against the frequency difference between the modes, mechanical thermal noise and damping, and coupling strengths of the cavity modes to the mirror.Comment: 9 pages, 4 figure