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In traditional Hanbury Brown and Twiss (HBT) schemes, the thermal intensity-intensity correlations are phase insensitive. Here we propose a modified HBT scheme with phase conjugation to demonstrate the phase-sensitive and nonfactorizable features for thermal intensity-intensity correlation speckle. Our scheme leads to results that are similar to those of the two-photon speckle. We discuss the possibility of the experimental realization. The results provide us a deeper insight of the thermal correlations and may lead to more significant applications in imaging and speckle technologies.
For decades, the world of financial advisors has been dominated by large investment banks such as Goldman Sachs. In recent years, user-contributed investment services such as SeekingAlpha and StockTwits have grown to millions of users. In this paper, we seek to understand the quality and impact of content on social investment platforms, by empirically analyzing complete datasets of SeekingAlpha articles (9 years) and StockTwits messages (4 years). We develop sentiment analysis tools and correlate contributed content to the historical performance of relevant stocks. While SeekingAlpha articles and StockTwits messages provide minimal correlation to stock performance in aggregate, a subset of authors contribute more valuable (predictive) content. We show that these authors can be identified via both empirical methods or by user interactions, and investments using their analysis significantly outperform broader markets. Finally, we conduct a user survey that sheds light on users views of SeekingAlpha content and stock manipulation.
The initial modulation in the scheme for Coherent electron Cooling (CeC) rests on the screening of the ion charge by electrons. However, in a CeC system with a bunched electron beam, inevitably, a long-range longitudinal space charge force is introdu ced. For a relatively dense electron beam, its force can be comparable to, or even greater than the attractive force from the ions. Hence, the influence of the space charge field on the modulation process could be important. If the 3-D Debye lengths are much smaller than the extension of the electron bunch, the modulation induced by the ion happens locally. Then, in that case, we can approximate the long-range longitudinal space charge field as a uniform electric field across the region. As detailed in this paper, we developed an analytical model to study the dynamics of ion shielding in the presence of a uniform electric field. We solved the coupled Vlasov-Poisson equation system for an infinite anisotropic electron plasma, and estimated the influences of the longitudinal space charge field to the modulation process for the experimental proof of the CeC principle at RHIC.
Local parity-odd domains are theorized to form inside a Quark-Gluon-Plasma (QGP) which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect (CME). The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this paper, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39 and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy, and tends to vanish by 7.7 GeV. The implications of these results for the CME will be discussed.
201 - Li-Gang Wang , Shi-Yao Zhu , 2013
We investigate the Goos-H{a}nchen (GH) shifts of partially coherent fields (PCFs) by using the theory of coherence. We derive a formal expression for the GH shifts of PCFs in terms of Mercers expansion, and then clearly demonstrate the dependence of the GH shift of each mode of PCFs on spatial coherence and beam width. We discuss the effect of spatial coherence on the resultant GH shifts, especially for the cases near the critical angles, such as totally reflection angle.
148 - Li-Gang Wang , Shi-Yao Zhu , 2013
This comment is to show that our simulation data, based on our theory and method in Ref. [J. Phys. B 41, 055401 (2008)], are also in agreement with the experimental data presented for $D_{p}-D_{s}$ in Ref. [Phys. Rev. Lett. textbf{109}, 213901 (2012) ]. We also demonstrate how to show the effect of spatial coherence on the GH shifts in this comment, therefore we disagree with the claims in Ref. [Phys. Rev. Lett. textbf{109}, 213901 (2012)].
180 - Li-Gang Wang 2011
It is shown that the spatial Goos-Hanchen shift is greatly affected by spatial coherence. A typical example is given.
115 - Li-Gang Wang , Yuen-Chi Tse , 2011
We have theoretically investigated the properties of electronic transport in graphene heterostructures, which are consisted of two different graphene superlattices with one-dimensional periodic potentials. It is found that such heterostructures posse ss an unusual tunneling state occurring inside the original forbidden gaps, and the electronic conductance is greatly enhanced and Fano factor is strongly suppressed near the energy of the tunneling state. Finally we present the matching condition of the impedance of the pseudospin wave for occuring the tunneling state by using the Bloch-wave expansion method.
In terms of operator, the two complementary quantities, the predictability and visibility, are reinvestigated in a two-way interferometer. One Hermitian operator and one non-Hermitian operator (composed of two Hermitian operators) are introduced for the predictability and visibility, respectively. The predictability and visibility can not be measured exactly simultaneously, due to the non-commutation between the two operators. The sum of the variances of the predictability and visibility (the total variance), is used to measure the uncertainty, which is linked to the complementarity relation through the equation, $(delta_P)^2+(delta_Vf)^2+P^2+V^2=2$ . This new description for the predictability and visibility connects the complementarity and the uncertainty relations, although neither of them can be derived directly from the other.
127 - Li-Gang Wang , Xi Chen 2010
In this paper, the electronic band structures and its transport properties in the gapped graphene superlattices, with one-dimensional (1D) periodic potentials of square barriers, are systematically investigated. It is found that a zero averaged wave- number (zero-$overline{k}$ ) gap is formed inside the gapped graphene-based superlattices, and the condition for obtaining such a zero-$overline{k}$ gap is analytically presented. The properties of this zero-$overline{k}$ gap including its transmission, conductance and Fano factor are studied in detail. Finally it is revealed that the properties of the electronic transmission, conductance and Fano factor near the zero-$overline{k}$ gap are very insensitive to the structural disorder for the finite graphene-based periodic-barrier systems.
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