In classically chaotic systems, small differences in initial conditions are exponentially magnified over time. However, it was observed experimentally that the (necessarily quantum) "branched flow" pattern of electron flux from a quantum point contact (QPC) traveling over a random background potential in two-dimensional electron gases remains substantially invariant to large changes in initial conditions. Since such a potential is classically chaotic and unstable to changes in initial conditions, it was conjectured that the origin of the observed stability is purely quantum mechanical, with no classical analog. In this Letter, we show that the observed stability is a result of the physics of the quantum point contact and the nature of the experiment. We show that the same stability can indeed be reproduced classically, or quantum mechanically. In addition, we explore the stability of the branched flow with regards to changes in the eigenmodes of the quantum point contact.

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An ultra-low power always-on keyword spotting (KWS) accelerator is implemented in 22nm CMOS technology, which is based on an optimized convolutional neural network (CNN). To reduce the power consumption while maintaining the system recognition accuracy, we first perform a bit-width quantization method on the proposed CNN to reduce the data/weight bit width required by the hardware computing unit without reducing the recognition accuracy. Then, we propose an approximate computing architecture for the quantized CNN using voltage-domain analog switching network based multiplication and addition unit. Implementation results show that this accelerator can support 10 keywords real time recognition under different noise types and SNRs, while the power consumption can be significantly reduced to 52µW.

We propose a method to realize enantiodiscrimination of chiral molecules based on quantum correlation function in a driven cavity-molecule system, where the chiral molecule is coupled with a quantized cavity field and two classical light fields to form a cyclic three-level model. According to the inherent properties of electric-dipole transition moments of chiral molecules, there is a π-phase difference in the overall phase of the cyclic three-level model for the left- and right-handed chiral molecules. Thus, the correlation function depends on this overall phase and is chirality-dependent. The analytical and numerical results indicate that the left- and right-handed chiral molecules can be discriminated by detecting quantum correlation function. Our work opens up a promising route to discriminate molecular chirality, which is an extremely important task in pharmacology and biochemistry.

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