Nonlinear Quantum Behavior of Ultrashort-Pulse Optical Parametric Oscillators

The quantum features of ultrashort-pulse optical parametric oscillators (OPOs) are theoretically investigated in the nonlinear regime near and above threshold. Starting from basic premises of input-output theory, we derive a general quantum model for pulsed OPOs subject to χ(2) interactions between a multimode signal cavity and a non-resonant broadband pump field, elucidating time scale conditions required for such pulsed OPOs to admit an input-output description. By employing a supermode decomposition of the nonlinear Lindblad operators governing pump-signal interactions, we perform multimode quantum simulations in the regime of strong nonlinearity and study effects such as pump depletion and corrections to the squeezing spectrum of the linearized model. We observe non-Gaussian states with Wigner function negativity and show that multimode interactions with the pump can act as decoherence channels

Quantum nondemolition measurements with optical parametric amplifiers for ultrafast universal quantum information processing

Realization of a room-temperature ultra-fast photon-number-resolving (PNR) quantum nondemolition (QND) measurement would have significant implications for photonic quantum information processing (QIP), enabling, e.g., deterministic quantum computation in discrete-variable architectures, but the requirement for strong coupling has hampered the development of scalable implementations. In this work, we propose and analyze a nonlinear-optical route to PNR QND using quadratic (i.e., $\chi^{(2)}$) nonlinear interactions. We show that the coherent pump field driving a phase-mismatched optical parametric amplifier (OPA) experiences displacements conditioned on the number of signal Bogoliubov excitations. A measurement of the pump displacement thus provides a QND measurement of the signal Bogoliubov excitations, projecting the signal mode to a squeezed photon-number state. We then show how our nonlinear OPA dynamics can be utilized for deterministically generating Gottesman-Kitaev-Preskill states only with additional Gaussian resources, offering an all-optical route for fault-tolerant QIP in continuous-variable systems. Finally, we place these QND schemes into a more traditional context by highlighting analogies between the phase-mismatched optical parametric oscillator and multilevel atom-cavity QED systems, by showing how continuous monitoring of the outcoupled pump quadrature induces conditional localization of the intracavity signal mode onto squeezed photon-number states. Our analysis suggests that our proposal may be viable in near-term $\chi^{(2)}$ nonlinear nanophotonics, highlighting the rich potential of OPA as a universal tool for ultrafast non-Gaussian quantum state engineering and quantum computation.Comment: The first two authors contributed equally to this work; 12 pages, 4 figure

Nonlinear Quantum Behavior of Ultrashort-Pulse Optical Parametric Oscillators

The quantum features of ultrashort-pulse optical parametric oscillators (OPOs) are theoretically investigated in the nonlinear regime near and above threshold. Starting from basic premises of input-output theory, we derive a general quantum model for pulsed OPOs subject to χ(2) interactions between a multimode signal cavity and a non-resonant broadband pump field, elucidating time scale conditions required for such pulsed OPOs to admit an input-output description. By employing a supermode decomposition of the nonlinear Lindblad operators governing pump-signal interactions, we perform multimode quantum simulations in the regime of strong nonlinearity and study effects such as pump depletion and corrections to the squeezing spectrum of the linearized model. We observe non-Gaussian states with Wigner function negativity and show that multimode interactions with the pump can act as decoherence channels

Simplex and triplex polymerase chain reaction (PCR) for identification of three medically important Candida species

Candida species are a major cause of invasive infections in both critically ill and immunocompromised patients. Hence, rapid identification of these pathogens may facilitate specific therapy and patient management. The development of rapid and specific diagnostic methods remains a challenge. Herein, we developed the simplex and triplex polymerase chain reaction (PCR) for the identification of three medically important Candida species namely C. albicans, C. parapsilosis and C. tropicalis. The developed methods target the phospholipase B gene (PLB). The primers designed achieved highly specific identification of the selected species using both the simplex PCR and the triplex PCR formats, which were confirmed by DNA sequencing. The primers did not show any non-specific amplification when tested with DNA from other Candida species and other fungal species such as Aspergillus and Cryptococcus. These results showed that the PLB gene provides a novel target that could be used for the detection of medically important Candida species from clinical specimens.Key words: Candida species, primers, phospholipase B gene (PLB), polymerase chain reaction (PCR)

A comprehensive spectroscopic, solvatochromic and photochemical analysis of 5-hydroxyquinoline and 8-hydroxyquinoline mono-azo dyes

A series of novel substituted-azo dyes 8-(aryldiazenyl)quinolin-5-ol (5a-i) were synthesized by the coupling reaction of 5-hydroxyquinoline with diazotized aniline derivatives in the presence of NaNO2 in HCl/H2O mixture. The study of the spectroscopic and solvatochromic properties were performed by FT-IR, 1H and 13C-NMR and UV-Visible spectroscopies. The tautomerism of these dyes was studied using the deuteration technique and solvatochromic measurements. Photochromic properties of these 5-hydroxyquinoline azo dyes were also examined via E/Z and Z/E photochemical isomerization reactions and compared with the existing 8-hydroxyquinoline analogous. The novel substituted-azo dyes exhibited higher Z/E thermal isomerization rates and have larger absorbance wavelength range than their 8-hydroxyquinoline analogous, making them potential molecular switches.FCT - Swinburne University of Technology(UID/QUI/00686/2020

Topological dynamics of an intrinsically disordered N-terminal domain of the human androgen receptor

ACKNOWLEDGEMENTS We are thankful to Eugene Shakhnovich (Harvard University) for critical reading of the manuscript, and to Peter Bolhuis and Ioana Ilie (University of Amsterdam) for technical discussions. The research in Mashaghi lab is supported by funding from Muscular Dystrophy Association (USA), Grant Number MDA628071, and Dutch Research Council (Nederlandse Organisatie voor Wetenschappelijk Onderzoek) through NWA-IDG (NWA.1228.192.309) and Open Competition XS (OCENW.XS.076).Peer reviewedPublisher PD

A new in vitro assay measuring direct interaction of nonsense suppressors with the eukaryotic protein synthesis machinery [preprint]

Nonsense suppressors (NonSups) treat premature termination codon (PTC) disorders by inducing the selection of near cognate tRNAs at the PTC position, allowing readthrough of the PTC and production of full-length protein. Studies of NonSup-induced readthrough of eukaryotic PTCs have been carried out using animals, cells or crude cell extracts. In these studies, NonSups can promote readthrough directly, by binding to components of the protein synthesis machinery, or indirectly, by inhibiting nonsense-mediated mRNA decay or by other mechanisms. Here we utilize a highly-purified in vitro system (Zhang et al., 2016. eLife 5: e13429) to measure exclusively direct NonSup-induced readthrough. Of 17 previously identified NonSups, 13 display direct effects, apparently via at least two different mechanisms. We can monitor such direct effects by single molecule FRET (smFRET). Future smFRET experiments will permit elucidation of the mechanisms by which NonSups stimulate direct readthrough, aiding ongoing efforts to improve the clinical usefulness of NonSups

Genetic diversity and population structure of long-tailed macaque (Macaca fascicularis) populations in Peninsular Malaysia

Background: The genetic diversity and structure of long-tailed macaques (Macaca fascicularis) in Peninsular Malaysia, a widely used non-human primate species in biomedical research, have not been thoroughly characterized. Methods: Thirteen sites of wild populations of long-tailed macaques representing six states were sampled and analyzed with 18 STR markers. Results: The Sunggala and Penang Island populations showed the highest genetic diversity estimates, while the Jerejak Island population was the most genetically discrete due to isolation from the mainland shelf. Concordant with pairwise Fst estimates, STRUCTURE analyses of the seven PCA-correlated clusters revealed low to moderate differentiation among the sampling sites. No association between geographic and genetic distances exists, suggesting that the study sites, including island study sites, are genetically if not geographically contiguous. Conclusions: The status of the genetic structure and composition of long-tailed macaque populations require further scrutiny to develop this species as an important animal model in biomedical research