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Artificial neural networks (ANNs) have now been widely used for industry applications and also played more important roles in fundamental researches. Although most ANN hardware systems are electronically based, optical implementation is particularly attractive because of its intrinsic parallelism and low energy consumption. Here, we propose and demonstrate fullyfunctioned all optical neural networks (AONNs), in which linear operations are programmed by spatial light modulators and Fourier lenses, and optical nonlinear activation functions are realized with electromagnetically induced transparency in laser-cooled atoms. Moreover, all the errors from different optical neurons here are independent, thus the AONN could scale up to a larger system size with final error still maintaining in a similar level of a single neuron. We confirm its capability and feasibility in machine learning by successfully classifying the order and disorder phases of a typical statistic Ising model. The demonstrated AONN scheme can be used to construct various ANNs of different architectures with the intrinsic parallel computation at the speed of light.

We present a new type of flow analysis, based on a particle-pair correlation function, in which there is no need for an event-by-event determination of the reaction plane. Consequently, the need to correct for dispersion in an estimated reaction plane does not arise. Our method also offers the option to avoid any influence from particle misidentification. Using this method, streamer chamber data for collisions of Ar+ KCl and Ari-BaI, at 1.2 GeV/nucleon are compared with predictions of a nuclear transport model.Many intermediate-energy heavy ion experiments have been directed toward the goal of inferring properties of the nuclear equation of state (EOS) [I]. In parallel with this effort, theoretical work in the area of nuclear transport models has focused on the task of identifying the most appropriate experimental observables for probing the EOS and on the related task of establishing a quantitative connection between such observables and the EOS [2]. Many factors, both theoretical and experimental, have contributed to the current lack of a Consensus on Data [3,4] from the Diogene and Plastic Ball detectors Support this assumption for rapidities other than the midrapidity region where the "squeeze-out" [5] effect can result in a more complex distribution. In the present study, we restrict our analysis to forward rapidities (see below). The maximum azimuthal anisotropy, as defined by Welke et al. [ 6 ] , is even a relatively coarse characterization of the compresl + h R=-sional potential energy at maximum density (in other 1-h ' words, a characterization of the EOS as relatively "hard" or "soft"). One such factor, for example, arises from the fact that detector inefficiencies and distortions can be difficult to simulate and quantify (particularly in the case of a 4n-detector), and this leads to systematic uncertainties in measurements of collective flow. This paper presents a new form of collective flow analysis for two data sets from the Bevalac streamer chamber. The most noteworthy feature of this new method is that it is designed to minimize the type of systematic uncertainty mentioned above; more specifically, the influences of particle misidentification and dispersion of the reaction plane can be removed.For a nonzero impact parameter, the beam direction ( z ) and the line joining the Centers of the nuclei determine the reaction plane, i.e., the X -2 plane. The azimuthal angle of a fragment in this coordinate system is We assume that the distribution function of 4 in an interval of rapidity centered on y , can be described by an expression of the form The method proposed by Welke et al. [6] for determining R in an experiment involves estimating 4 in Eqs. (1) and (2) using the relation 4=+obs-+R, where +obs is the observed azimuth of a fragment, and +R is the estimated azimuth of the reaction plane as deter.mined from the observed fragments in the final state. This method requires that the resulting R be corrected upward, to allow for the fact that 4R is distributed about + = O with a finite dispersion. Eac...

Non-Hermitian optical systems with parity-time (PT) symmetry have recently revealed many intriguing prospects that outperform conservative structures. The prevous works are mostly rooted in complex arrangements with controlled gain-loss interplay. Here, we demonstrate anti-PT symmetry inherent in nonlinear optical interactions based upon forward optical four-wave mixing in a laser-cooled atomic ensemble with negligible linear gain and loss. We observe the pair of frequency modes undergo a nontrivial anti-PT phase transition between coherent power oscillation and optical parametric amplification in presence of a large phase mismatch.