Entanglement and chaos in warped conformal field theories

Various aspects of warped conformal field theories (WCFTs) are studied including entanglement entropy on excited states, the Renyi entropy after a local quench, and out-of-time-order four-point functions. Assuming a large central charge and dominance of the vacuum block in the conformal block expansion, (i) we calculate the single-interval entanglement entropy on an excited state, matching previous finite temperature results by changing the ensemble; and (ii) we show that WCFTs are maximally chaotic, a result that is compatible with the existence of black holes in the holographic duals. Finally, we relax the aforementioned assumptions and study the time evolution of the Renyi entropy after a local quench. We find that the change in the Renyi entropy is topological, vanishing at early and late times, and nonvanishing in between only for charged states in spectrally-flowed WCFTs.Comment: 31 pages; v2: corrected typos, matches published versio

Intelligent Voice Augmented Reality Interactive

Voice enables people to transmit information better and more quickly, and people can control all kinds of machines to communicate and work by intelligent voice. This paper intends to use intelligent voice to achieve new cloud classroom teaching. The effect that the teacher can move the picture in real time through voice control and reply accordingly can be achieved by speech synthesis, speech recognition and voice interaction technology. The efficiency of the classroom is improved while the interest of the classroom has been enhanced

A dual-grating InGaAsP/InP DFB laser integrated with an SOA for THz generation

We report a dual-mode semiconductor laser that has two gratings with different periods below and above the active layer. A semiconductor optical amplifier (SOA), which is integrated with the dual-mode laser, plays an important role in balancing the optical power and reducing the linewidths of the emission modes. A stable two mode emission with the 13.92-nm spacing can be obtained over a wide range of distributed feedback and SOA injection currents. Compared with other types of dual-mode lasers, our device has the advantages of simple structure, compact size, and low fabrication cost

Bifurcations for a predator–prey system with two delays

AbstractIn this paper, a predator–prey system with two delays is investigated. By choosing the sum τ of two delays as a bifurcation parameter, we show that Hopf bifurcations can occur as τ crosses some critical values. By deriving the equation describing the flow on the center manifold, we can determine the direction of the Hopf bifurcations and the stability of the bifurcating periodic solutions. In addition, special attention is paid to the global continuation of local Hopf bifurcations. Using a global Hopf bifurcation result of [J. Wu, Symmetric functional differential equations and neural networks with memory, Trans. Amer. Math. Soc. 350 (1998) 4799–4838], we may show the global existence of periodic solutions

Fully integrated multi-optoelectronic synthesizer for THz pumping source in wireless communications with rich backup redundancy and wide tuning range

We report a monolithic photonic integrated circuit (PIC) for THz communication applications. The PIC generates up to 4 optical frequency lines which can be mixed in a separate device to generate THz radiation, and each of the optical lines can be modulated individually to encode data. Physically, the PIC comprises an array of wavelength tunable distributed feedback lasers each with its own electro-absorption modulator. The lasers are designed with a long cavity to operate with a narrow linewidth, typically <4 MHz. The light from the lasers is coupled via an multimode interference (MMI) coupler into a semiconductor optical amplifier (SOA). By appropriate selection and biasing of pairs of lasers, the optical beat signal can be tuned continuously over the range from 0.254 THz to 2.723 THz. The EAM of each channel enables signal leveling balanced between the lasers and realizing data encoding, currently at data rates up to 6.5 Gb/s. The PIC is fabricated using regrowth-free techniques, making it economic for volume applications, such for use in data centers. The PIC also has a degree of redundancy, making it suitable for applications, such as inter-satellite communications, where high reliability is mandatory

Autotaxin is induced by TSA through HDAC3 and HDAC7 inhibition and antagonizes the TSA-induced cell apoptosis

<p>Abstract</p> <p>Background</p> <p>Autotaxin (ATX) is a secreted glycoprotein with the lysophospholipase D (lysoPLD) activity to convert lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA), a bioactive lysophospholipid involved in diverse biological actions. ATX is highly expressed in some cancer cells and contributes to their tumorigenesis, invasion, and metastases, while in other cancer cells ATX is silenced or expressed at low level. The mechanism of ATX expression regulation in cancer cells remains largely unknown.</p> <p>Results</p> <p>In the present study, we demonstrated that trichostatin A (TSA), a well-known HDAC inhibitor (HDACi), significantly induced ATX expression in SW480 and several other cancer cells with low or undetectable endogenous ATX expression. ATX induction could be observed when HDAC3 and HDAC7 were down-regulated by their siRNAs. It was found that HDAC7 expression levels were low in the cancer cells with high endogenous ATX expression. Exogenous over-expression of HDAC7 inhibited ATX expression in these cells in a HDAC3-dependent manner. These data indicate that HDAC3 and HDAC7 collaboratively suppress ATX expression in cancer cells, and suggest that TSA induce ATX expression by inhibiting HDAC3 and HDAC7. The biological significance of this regulation mechanism was revealed by demonstrating that TSA-induced ATX protected cancer cells against TSA-induced apoptosis by producing LPA through its lysoPLD activity, which could be reversed by BrP-LPA and S32826, the inhibitors of the ATX-LPA axis.</p> <p>Conclusions</p> <p>We have demonstrated that ATX expression is repressed by HDAC3 and HDAC7 in cancer cells. During TSA treatment, ATX is induced due to the HDAC3 and HDAC7 inhibition and functionally antagonizes the TSA-induced apoptosis. These results reveal an internal HDACi-resistant mechanism in cancer cells, and suggest that the inhibition of ATX-LPA axis would be helpful to improve the efficacy of HDACi-based therapeutics against cancer.</p