Parity-violating macroscopic force between chiral molecules and source mass

A theory concerning non-zero macroscopic chirality-dependent force between a source mass and homochiral molecules due to the exchange of light particles is presented in this paper. This force is proposed to have opposite sign for molecules with opposite chirality. Using the central field approximation, we calculate this force between a copper block and a vessel of chiral molecules (methyl phenyl carbinol nitrite). The magnitude of force is estimated with the published limits of the scalar and pseudo-scalar coupling constants. Based on our theoretical model, this force may violate the equivalence principle when the homochiral molecules are used to be the test masses.Comment: 10 pages, 1 figur

A Two-Level Speaker Identification System via Fusion of Heterogeneous Classifiers and Complementary Feature Cooperation

We present a new architecture to address the challenges of speaker identification that arise in interaction of humans with social robots. Though deep learning systems have led to impressive performance in many speech applications, limited speech data at training stage and short utterances with background noise at test stage present challenges and are still open problems as no optimum solution has been reported to date. The proposed design employs a generative model namely the Gaussian mixture model (GMM) and a discriminative model—support vector machine (SVM) classifiers as well as prosodic features and short-term spectral features to concurrently classify a speaker’s gender and his/her identity. The proposed architecture works in a semi-sequential manner consisting of two stages: the first classifier exploits the prosodic features to determine the speaker’s gender which in turn is used with the short-term spectral features as inputs to the second classifier system in order to identify the speaker. The second classifier system employs two types of short-term spectral features; namely mel-frequency cepstral coefficients (MFCC) and gammatone frequency cepstral coefficients (GFCC) as well as gender information as inputs to two different classifiers (GMM and GMM supervector-based SVM) which in total leads to construction of four classifiers. The outputs from the second stage classifiers; namely GMM-MFCC maximum likelihood classifier (MLC), GMM-GFCC MLC, GMM-MFCC supervector SVM, and GMM-GFCC supervector SVM are fused at score level by the weighted Borda count approach. The weight factors are computed on the fly via Mamdani fuzzy inference system that its inputs are the signal to noise ratio and the length of utterance. Experimental evaluations suggest that the proposed architecture and the fusion framework are promising and can improve the recognition performance of the system in challenging environments where the signal-to-noise ratio is low, and the length of utterance is short; such scenarios often arise in social robot interactions with humans

TEMPERATURE VARIATION OF HYPERFINE MAGNETIC FIELD IN Co2MnZ AND Co2TiZ (Z = Si, Ge, Sn)

The temperature variation of the hyperfine magnetic field (hmf) at Cd-111 in Co2MnZ and at Sn-119 in Co2TiZ (Z = Si, Ge, Sn) was measured respectively by perturbed angular correlation and Mössbauer techniques. In Co2MnZ the hmf follows the temperature variation of magnetization, but in Co2TiZ it deviates significantly

Mössbauer studies of57Co-doped layered perovskites

Mössbauer spectra of Co-doped polycrystalline or single-crystal samples of layered perovskites La Mo (M=Cu, Co, Ni) and R CuO (R=Nd, Eu, Gd) were recorded at room temperature and below. Of the samples studied, only La CuO shows a widely separated doublet at room temperature and a single clearly resolved sextet well below T . © 1990 J.C. Baltzer A.G. Scientific Publishing Company. 57 2 4 2 4 2 4

Mössbauer studies of57Co-doped layered perovskites

Mössbauer spectra of57Co-doped polycrystalline or single-crystal samples of layered perovskites La2Mo4 (M=Cu, Co, Ni) and R2CuO4 (R=Nd, Eu, Gd) were recorded at room temperature and below. Of the samples studied, only La2CuO4 shows a widely separated doublet at room temperature and a single clearly resolved sextet well below TN. © 1990 J.C. Baltzer A.G. Scientific Publishing Company

Mikheev-Smirnov-Wolfenstein effect in chiral molecules

In a recent article (Phys Rev A 2009, 80, 012110), we have proposed an alternative method to measure the parity-violating energy difference between enantiomers of chiral molecules by modifying the dynamics of the two-state system using an external chiral field, in particular circularly polarized light. When this field is properly tuned, the two-state system becomes resonant, thus being maximal the probability of interconversion between enantiomers. In this work, we show that the resonance found in our previous work is identical to that found in two-flavor neutrino oscillations, known as Mikheev-Smirnov-Wolfenstein (MSW) resonance. We use some analogies between neutrinos and chiral molecules to derive some interesting properties of the oscillations between enantiomers. In particular, we obtain an expression for the transition probability between them when their energy difference is time-dependent. © 2010 Wiley Periodicals, Inc.P. B. acknowledges the organizers of QSCP-XIV for their kind invitation to participate in the workshop.Peer Reviewe