ALBERT

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Baumgartner, M. F., Bonnell, J., Van Parijs, S. M., Corkeron, P. J., Hotchkin, C., Ball, K., Pelletier, L., Partan, J., Peters, D., Kemp, J., Pietro, J., Newhall, K., Stokes, A., Cole, T. V. N., Quintana, E., & Kraus, S. D. Persistent near real-time passive acoustic monitoring for baleen whales from a moored buoy: System description and evaluation. Methods in Ecology and Evolution, 10(9), (2019): 1476-1489, doi: 10.1111/2041-210X.13244.

Description: 1. Managing interactions between human activities and marine mammals often relies on an understanding of the real‐time distribution or occurrence of animals. Visual surveys typically cannot provide persistent monitoring because of expense and weather limitations, and while passive acoustic recorders can monitor continuously, the data they collect are often not accessible until the recorder is recovered. 2. We have developed a moored passive acoustic monitoring system that provides near real‐time occurrence estimates for humpback, sei, fin and North Atlantic right whales from a single site for a year, and makes those occurrence estimates available via a publicly accessible website, email and text messages, a smartphone/tablet app and the U.S. Coast Guard's maritime domain awareness software. We evaluated this system using a buoy deployed off the coast of Massachusetts during 2015–2016 and redeployed again during 2016–2017. Near real‐time estimates of whale occurrence were compared to simultaneously collected archived audio as well as whale sightings collected near the buoy by aerial surveys. 3. False detection rates for right, humpback and sei whales were 0% and nearly 0% for fin whales, whereas missed detection rates at daily time scales were modest (12%–42%). Missed detections were significantly associated with low calling rates for all species. We observed strong associations between right whale visual sightings and near real‐time acoustic detections over a monitoring range 30–40 km and temporal scales of 24–48 hr, suggesting that silent animals were not especially problematic for estimating occurrence of right whales in the study area. There was no association between acoustic detections and visual sightings of humpback whales. 4. The moored buoy has been used to reduce the risk of ship strikes for right whales in a U.S. Coast Guard gunnery range, and can be applied to other mitigation applications.

Description: We thank Annamaria Izzi, Danielle Cholewiak and Genevieve Davis of the NOAA NEFSC for assistance in developing the analyst protocol. We are grateful to the NOAA NEFSC aerial survey observers (Leah Crowe, Pete Duley, Jen Gatzke, Allison Henry, Christin Khan and Karen Vale) and the NEAq aerial survey observers (Angela Bostwick, Marianna Hagbloom and Paul Nagelkirk). Danielle Cholewiak and three anonymous reviewers provided constructive criticism on earlier drafts of the manuscript. Funding for this project was provided by the NOAA NEFSC, NOAA Advanced Sampling Technology Work Group, Environmental Security Technology Certification Program of the U.S. Department of Defense, the U.S. Navy's Living Marine Resources Program, Massachusetts Clean Energy Center and the Bureau of Ocean Energy Management. Funding from NOAA was facilitated by the Cooperative Institute for the North Atlantic Region (CINAR) under Cooperative Agreement NA14OAR4320158.

Description: Author Posting. © Royal Society, 2018. This article is posted here by permission of Royal Society for personal use, not for redistribution. The definitive version was published in Proceedings of the Royal Society Open Science 5(12) (2018): 181358. doi: 10.1098/rsos.181358.

Description: The settlement of reef-building corals is critical to the survival and recovery of reefs. Recent evidence indicates that coral larvae orient towards reef sound, yet the components of the acoustic environment that may attract coral larvae and induce settlement are unknown. Here we investigated the effects of ambient soundscapes on settlement of Porites astreoides coral larvae using in situ chambers on reefs differing in habitat quality (coral and fish abundance). Mean larval settlement was twice as high in an acoustic environment with high levels of low-frequency sounds, typical of a high-quality, healthy reef; this result was observed in both natural light and dark treatments. Overall, the enhancement of coral settlement by soundscapes typical of healthy reefs suggests a positive feedback where soundscape properties of reefs with elevated coral and fish abundance may facilitate coral recruitment.

Description: This study is funded by NSF Biological Oceanography award 15-36782 which supported all authors.

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Capotondi, A., Jacox, M., Bowler, C., Kavanaugh, M., Lehodey, P., Barrie, D., Brodie, S., Chaffron, S., Cheng, W., Dias, D. F., Eveillard, D., Guidi, L., Iudicone, D., Lovenduski, N. S., Nye, J. A., Ortiz, I., Pirhalla, D., Buil, M. P., Saba, V., Sheridan, S., Siedlecki, S., Subramanian, A., de Vargas, C., Di Lorenzo, E., Doney, S. C., Hermann, A. J., Joyce, T., Merrifield, M., Miller, A. J., Not, F., & Pesant, S. Observational needs supporting marine ecosystems modeling and forecasting: from the global ocean to regional and coastal systems. Frontiers in Marine Science, 6, (2019): 623, doi:10.3389/fmars.2019.00623.

Description: Many coastal areas host rich marine ecosystems and are also centers of economic activities, including fishing, shipping and recreation. Due to the socioeconomic and ecological importance of these areas, predicting relevant indicators of the ecosystem state on sub-seasonal to interannual timescales is gaining increasing attention. Depending on the application, forecasts may be sought for variables and indicators spanning physics (e.g., sea level, temperature, currents), chemistry (e.g., nutrients, oxygen, pH), and biology (from viruses to top predators). Many components of the marine ecosystem are known to be influenced by leading modes of climate variability, which provide a physical basis for predictability. However, prediction capabilities remain limited by the lack of a clear understanding of the physical and biological processes involved, as well as by insufficient observations for forecast initialization and verification. The situation is further complicated by the influence of climate change on ocean conditions along coastal areas, including sea level rise, increased stratification, and shoaling of oxygen minimum zones. Observations are thus vital to all aspects of marine forecasting: statistical and/or dynamical model development, forecast initialization, and forecast validation, each of which has different observational requirements, which may be also specific to the study region. Here, we use examples from United States (U.S.) coastal applications to identify and describe the key requirements for an observational network that is needed to facilitate improved process understanding, as well as for sustaining operational ecosystem forecasting. We also describe new holistic observational approaches, e.g., approaches based on acoustics, inspired by Tara Oceans or by landscape ecology, which have the potential to support and expand ecosystem modeling and forecasting activities by bridging global and local observations.

Description: This study was supported by the NOAA’s Climate Program Office’s Modeling, Analysis, Predictions, and Projections (MAPP) Program through grants NA17OAR4310106, NA17OAR4310104, NA17OAR4310108, NA17OAR4310109, NA17OAR4310110, NA17OAR4310111, NA17OAR4310112, and NA17OAR4310113. This manuscript is a product of the NOAA/MAPP Marine Prediction Task Force. The Tara Oceans consortium acknowledges support from the CNRS Research Federation FR2022 Global Ocean Systems Ecology and Evolution, and OCEANOMICS (grant agreement ‘Investissement d’Avenir’ ANR-11-BTBR-0008). This is article number 95 of the Tara Oceans consortium. MK and SD acknowledge support from NASA grant NNX14AP62A “National Marine Sanctuaries as Sentinel Sites for a Demonstration Marine Biodiversity Observation Network (MBON)” funded under the National Ocean Partnership Program (NOPP RFP NOAA-NOS-IOOS-2014-2003803 in partnership between NOAA, BOEM, and NASA), and the NOAA Integrated Ocean Observing System (IOOS) Program Office. WC, IO, and AH acknowledge partial support from the Joint Institute for the Study of the Atmosphere and Ocean (JISAO) under NOAA Cooperative Agreement NA15OAR4320063, Contribution No. 2019-1029. This study received support from the European H2020 International Cooperation project MESOPP (Mesopelagic Southern Ocean Prey and Predators), grant agreement no. 692173.

Description: The NASA Glenn Research Centers DGEN Aeropropulsion Research Turbofan (DART) is based on the Price Induction DGEN380a small, ~500-lbf thrust class, high-bypass, geared-turbofan engine with a separate flow nozzle. The general characteristics of the DART make it an ideal candidate for utilization as a test bed for engine aeroacoustic research in a relevant performance environment. The DART was used to document the efficacy of acoustic liners installed in the inlet of the DGEN380. An advanced multi-degree-of-freedom liner (MDOF) was designed and tested, along with a traditional single-degree-of- freedom liner (SDOF), and those results compared to a hard-wall baseline inlet. Farfield acoustic data were acquired from an external array, evaluated, and reported here-in terms of overall, broadband, and tonal components of the insertion loss.

Description: The purpose of this study is to characterize auditory filters at low frequencies, defined as below about 100 Hz. Three experiments were designed and executed. They were conducted in the Exterior Effects Room at the NASA Langley Research Center, a psychoacoustic facility designed for presentation of aircraft flyover sounds to groups of test subjects. The first experiment measured 36 subjects hearing threshold for pure tones (at 25, 31.5, 40, 50, 63 and 80 Hz) in quiet conditions. The subjects, male and female, had a wide age range. This experiment allowed the performance of the test facility to be assessed and also provided screened test subjects for participation in subsequent experiments. The second and third experiments used 20 and 10 test subjects, respectively, and measured psychophysical tuning curves (PTCs) that describe auditory filters with center frequencies of approximately 63 and 50 Hz. The latter is assumed to be the lowest (bottom) auditory filter; thus, sounds at frequencies below about 50 Hz are perceived via the lower skirt of this lowest filter. All experiments used an adaptive, three-alternative forced-choice test procedure using either variable level tones or variable level, narrowband noise maskers. Measured PTCs were found to be very similar to other recently published data, both in terms of mean values and intersubject variation, despite different experimental protocols, different test facilities, and a wide range in subjects age.

Description: The purpose of this presentation is to give an overview of our findings, lessons learned, engineering controls implemented, and results of sound mitigation implementation at NASA Space Environments Complex in relation to Thermal Vacuum Testing.

Description: Aeroacoustic predictions of slat noise from the 30P30N three-element high-lift system at high angles of attack are presented using a zonal hybrid RANS-LES method. The simulations are part of the 5th AIAA Benchmark problems for Airframe Noise Computations (BANC-V) Workshop. An economical approach utilizing structured overset grids with spatially varying span-wise grid resolution and a high-order accurate finite difference method is described. The method is utilized for near-field predictions at three angles of attack: = 5.5, 9.5, and 14.0 degrees. Far-field noise is obtained by propagating the near-field solution using a permeable surface Ffowcs Williams-Hawkings (FWH) method. Good agreement is obtained with both near-field and far-field Power Spectral Density (PSD) data from an experimental study of the 30P30N in the 2m x 2m Kevlar-wall wind tunnel at the Japan Aerospace Exploration Agency (JAXA). Specifically, the reduction in narrow band peaks and overall broadband noise levels with increasing angle of attack is captured well using the zonal hybrid RANS-LES method.

Description: This report documents the technical accomplishments of the project, Acoustic Emission- Based Health Monitoring of Space Launch System Structures, sponsored by the National Aeronautics and Space Administration (Award No. NNM13AA12G). As the project title suggests, the goal of the project was to develop a structural health monitoring (SHM) system for Space Launch System (SLS) vehicles based on acoustic emission (AE) or AE-like signals. Such a system will enhance SLS reliability by identifying the damage locations and type of damage when the damage is initiated. This SHM system would also lead to reduced maintenance costs by enabling ground support equipment to inspect only SLS elements or parts that are likely to be damaged. Finally, it will facilitate lean designs that meet tolerance levels specified by barely detectable damage. By avoiding excess conservatism in this manner, this SHM system will further reduce manufacturing costs of SLS vehicles.

Description: No abstract available

Description: No abstract available

Description: The existing ban on commercial supersonic flight overland is largely due to the effects of loud and startling sonic booms on communities. NASA is planning a nationwide campaign of community response surveys using the experimental X-59 Quiet SuperSonic Technology (X-59 QueSST) aircraft to understand how communities perceive the sounds of quiet supersonic flight. The X-59 community response survey data will be presented to noise regulators, who are considering replacing the ban with a noise-based certification limit so quiet supersonic vehicles can fly over land. In this document, we use pilot community response survey data to explore and assess multiple approaches to statistically model the dose-response relationship between single-event sonic boom sound exposure and human annoyance. The models have two primary functionsestimating two types of quantities that support setting regulations and experimental design of future surveys.

Description: No abstract available

Description: The Advanced Noise Control Fan (ne Active Noise Control Fan - ANCF) was utilized in the design, test, and evaluation for technical risk mitigation of most of the innovative fan noise reduction technologies developed by NASA over the past 20 years. The ANCF is a low-speed, ducted fan, testbed for measuring and understanding fan-generated aeroacoustics, duct propagation, and radiation to the farfield. It is considered a low Technology Readiness Level testbed. The international aeroacoustics research community employed the ANCF to facilitate advancement of multiple noise reduction and measurement technologies, and for code validation. From 1994 to 2016, it was located in the NASA Glenn Research Centers Aero-Acoustic Propulsion Laboratory. In 2016 the ANCF was transferred to the University of Notre Dame where it is expected to continue to positively impact ducted fan aeroacoustic research and provide STEM support. This paper summarizes the capabilities and contributions of the ANCF to the field by documenting its history. Limited data is presented, focusing on a description of the configurations, goals, and objectives of representative ANCF tests. This provides an overview of the progress of aeroacosustic research as implemented on the ANCF, as well as a background for its continued usage.

Description: The Advanced Noise Control Fan (ANCF) (formerly the Active Noise Control Fan) was utilized in the design, test, and evaluation for technical risk mitigation of most of the innovative fan noise reduction technologies developed by NASA over the past 20 years (Figure 3). The ANCF is a low-speed ducted-fan testbed for measuring and understanding fan-generated aeroacoustics, duct propagation, and radiation to the far field. It is considered a low technology readiness level (TRL) testbed. The international aeroacoustics research community employed the ANCF to facilitate advancement of multiple noise reduction and measurement technologies and for code validation. From 1994 to 2016, it was located in the NASA Glenn Research Centers Aero-Acoustic Propulsion Laboratory (AAPL). In 2016, the ANCF was transferred to the University of Notre Dame (UND) where it is expected to continue to positively impact ducted-fan aeroacoustic research. This paper summarizes the capabilities and contributions of the ANCF to the field by documenting its history.

Description: Recent interest in commercial supersonic flight has highlighted the need to accurately predict Effective Perceived Noise Levels (EPNL) for aircraft and, since the dominant noise source at takeoff will likely be jet noise, specifically jet noise contributions. The current study compares predictions from historical jet-noise models within NASAs Aircraft Noise Prediction Program and scale-model data to measurements made in a Learjet 25 flight test. The noise levels from the predictions and scale-model data were below those for the flight data by 2.5 3.5, 1 2, and 3 5 EPNdB for the SAE model, the Stone Jet model, and the scale-model data, respectively. Tones and broadband haystacks were identified in the flight spectra that are not associated with jet noise which increased the flight EPNL by at least 0.5 EPNdB over that computed from spectra with the tones and haystacks removed. The study highlights the need for accurate exhaust temperature measurements, aircraft flight position information, and averaging data across a line of microphones in flight tests. For example, a 100 F to 200 F difference in jet exhaust temperature is enough to explain the differences between flight, model scale, and prediction comparisons.

Description: A model-scale exhaust system was tested to validate low-noise concepts and noise prediction methods. The tests involved far-field acoustics, translating phased array, and particle image velocimetry; this report covers the far-field acoustic measurements. Data were acquired for a series of nozzles with different chevron designs, both uninstalled and installed on a representative aircraft planform. The impact of the various chevron treatments on the far-field noise was documented, along with the impact of the pylon and planform. For the baseline nozzle, installation produced a 2EPNdB reduction, as assumed in system studies. Chevrons were used to shift noise sources upstream to maximize the installation benefits and to reduce unshielded sources downstream. These resulted in reductions of 4-5EPNdB relative to the uninstalled baseline nozzle. Detailed analysis of spectral directivities behind the integrated EPNL metric gave insight into how well these concepts actually work. When correlated with particle image velocimetry measurements and phased array measurements, reported in companion papers, the explanation of acoustic benefits from top-mounted propulsion is clear as is the path toward optimization of the concept.

Description: A model-scale exhaust system was tested to validate low-noise propulsion concepts and noise prediction methods. The tests involved far-field acoustics, phased array, and particle image velocimetry (PIV). This paper covers the particle image velocimetry portion. Data was acquired at NASA Glenn's Aero-Acoustic Propulsion Lab for a series of nozzles with different chevron designs, both uninstalled and installed on a representative aircraft planform. The impact of the various chevron treatments on the turbulent velocity field was documented, along with the impact of the pylon and planform. When correlated with far-field acoustic measurements and phased array measurements, reported in companion papers, the explanation of acoustic benefits from top-mounted propulsion is clear as is the path toward optimization of the concept.

Description: Reynolds-Averaged Navier-Stokes simulations have been performed on a three-stream invertedvelocity profile nozzle with and without various configurations of chevrons attached.The nozzle was mounted on a planform to imitate an engine mounted above a wing, shieldingground observers from engine noise. Several chevron designs intended to aggressively mix thejet and move noise sources upstream for shielding were examined to investigate their effects onnoise and thrust. Numerical results for the baseline nozzle and one chevron configuration werecompared with far-field noise and particle image velocimetry data obtained in NASA GlennResearch Centers Aero-Acoustic Propulsion Laboratory. A configuration in which chevronsalternate penetration into the primary stream and tertiary fan stream was explored using theModern Design of Experiments approach. Short, high-penetration chevrons demonstrated asignificant noise reduction for a relatively small thrust penalty.

Description: An application program interface (API) has been developed for the creation and access of structured data files generated by microphone phased arrays utilized in aeroacoustics research. Two structured binary file formats are supported, namely NetCDF (Network Common Data Form) and HDF5 (Hierarchical Data Format) files. The API consists of a library of routines callable from C, Fortran or Matlab, with native versions of the API provided for each language. The libraries are divided into categories for file handling, file definition and initialization, data writing, data recovery, and error handling. The API is intended to provide a mechanism for generating self-describing binary files for long-term archiving of raw and processed data generated by phased array systems.

Description: The main purpose of this study is to examine the audibility of multiple, low-frequency tones that are placed in distinct auditory channels. Three experiments are described, the goals of which are to determine if the presence of sound in multiple channels results in enhanced audibility and to assess the applicability of the Statistical Summation Model (SSM) to this frequency range. This model predicts that for the case of multiple signals that are in separate auditory channels, implying statistical independence, each with sensitivity value d prime of i, the resulting total sensitivity is given by the square root of the sum of the squares of the individual d prime of i values. In common with previous studies conducted at higher frequencies, the signals are pure tones and the maskers are broadband noise. The requirement that low frequency tones be placed in separate auditory filters limited the number of tones to a maximum of three. The first of the three experiments measured the change in masked thresholds for two- and three-tone signals relative to the level of the equally-detectable single tones. The multiple tone signals were composed of combinations of 55, 120 and 200 Hz tones. The measured changes in thresholds exceeded those predicted by the SSM, although they did not differ statistically from the model predictions. The second experiment employed the same overall approach but acquired more data and concentrated on the three-tone signal. Once again, the measured changes in masked threshold exceeded the model predictions, this time to a statistically-significant degree. Two issues were postulated with the potential to yield inflated changes in masked threshold: interaction between tones resulting in perceptible intermodulation/difference tones, and the assumption that the tones were in distinct auditory filters and statistically independent of one another. The third experiment used two sets of three-tone signals to address these latter concerns. The first set of three tones was composed of harmonically related tone frequencies of 55, 110 and 165 Hz, which was an attempt to reduce effects of intermodulation difference tones. The second set of three tones was chosen to be 110, 220 and 330 Hz, again reducing effects of difference tones, but also providing greater separation between tones. Results for the first set of three tones compared to those of the earlier experiments indicated that intermodulation was not an important effect. The second set of three tones (110, 220, 330 Hz) yielded changes in masked thresholds that, on average, were in good agreement with the SSM, although intersubject variability was large and prohibited a definitive conclusion regarding the concern that tone spacing was inadequate. The results of the three experiments showed that the masked threshold of sounds with multiple (two or three) equally-detectable low frequency tones was lower than those of the single tones. In other words, it is clear that audibility is enhanced by the presence of signals in multiple auditory filters. This finding is consistent with most previous research conducted at higher frequencies. In contrast with previous research, test subjects were, on average, able to detect multitone sounds at lower levels than those predicted using the SSM. Analyses that included Monte Carlo simulations showed that normally distributed errors in the single tone thresholds result in biased estimates of the thresholds of multitone sounds. This phenomenon is likely responsible for at least a substantial fraction of the unexpected deviation of measurements from SSM predictions.

Description: The Advanced Noise Control Fan (Active Noise Control Fan - ANCF) was utilized in the design, test, and evaluation for technical risk mitigation of most of the innovative fan noise reduction technologies developed by NASA over the past 20 years. The ANCF is a low-speed ducted fan test bed for measuring and understanding fan-generated aeroacoustics, duct propagation, and radiation to the farfield. It is considered a low Technology Readiness Level testbed. The international aeroacoustics research community employed the ANCF to facilitate advancement of multiple noise reduction and measurement technologies, and for code validation. From 1994 to 2016, it was located in the NASA Glenn Research Center's Applied Aero Propulsion Laboratory. In 2016 the ANCF was transferred to the University of Notre Dame where it is expected to continue to positively impact ducted fan aeroacoustic research. This paper summarizes the capabilities and contributions of the ANCF to the field by documenting its history.

Description: To determine the best acoustic sampling period for obtaining fish biomass estimates of a Mediterranean deep reservoir in Tunisia, we carried out day and night surveys in each of four seasons [spring (April), summer (September), autumn (December) and winter (March)]. A Simrad EK60 echosounder, equipped with two 120 kHz split-beam transducers for simultaneous horizontal and vertical beaming, was used to sample the entire water column. Data collected in December were not usable because fish merged with methane gas bubbles. However, fish abundance varied across the other seasons with a peak in acoustic biomass observed during summer nighttime hours that was associated with high water temperatures. Across seasons, the fish occupied the entire water column, and fish schools were rarely observed. The preferential timeframe (i.e. maximum fish detectability and low gas flux) for acoustic sampling was nighttime hours in summer and daytime hours during spring and winter. Our findings highlight the importance of collecting data across seasons and photoperiods when determining an acoustic sampling strategy.

Description: This is the pre-peer reviewed version of the following article: [Djemali I., Laouar H. Acoustic fish biomass assessment in a deep Tunisian reservoir: effects of season and diel rhythm on survey results. in: African Journal of Aquatic Science. 2017. IN PRESS], which has been published in final form at [https://doi.org/10.2989/16085914.2016.1277181]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Description: In Press

Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Marine Science 5 (2018): 158, doi:10.3389/fmars.2018.00158.

Description: In autumn 2015, several sources reported observations of large amounts of gelatinous material in a large north Norwegian fjord system, either caught when trawling for other organisms or fouling fishing gear. The responsible organism was identified as a physonect siphonophore, Nanomia cara, while a ctenophore, Beroe cucumis, and a hydromedusa, Modeeria rotunda, were also registered in high abundances on a couple of occasions. To document the phenomena, we have compiled a variety of data from concurrent fisheries surveys and local fishermen, including physical samples, trawl catch, and acoustic data, photo and video evidence, and environmental data. Because of the gas-filled pneumatophore, characteristic for these types of siphonophores, acoustics provided detailed and unique insight to the horizontal and vertical distribution and potential abundances (~0.2–20 colonies·m−3) of N. cara with the highest concentrations observed in the near bottom region at ~320 m depth in the study area. This suggests that these animals were retained and accumulated in the deep basins of the fjord system possibly blooming here because of favorable environmental conditions and potentially higher prey availability compared to the shallower shelf areas to the north. Few cues as to the origin and onset of the bloom were found, but it may have originated from locally resident siphonophores. The characteristics of the deep-water masses in the fjord basins were different compared to the deep water outside the fjord system, suggesting no recent deep-water import to the fjords. However, water-masses containing siphonophores (not necessarily very abundant), may have been additionally introduced to the fjords at intermediate depths, with the animals subsequently trapped in the deeper fjord basins. The simultaneous observations of abundant siphonophores, hydromedusae, and ctenophores in the Lyngen-Kvænangen fjord system are intriguing, but difficult to provide a unified explanation for, as the organisms differ in their biology and ecology. Nanomia and Beroe spp. are holopelagic, while M. rotunda has a benthic hydroid stage. The species also have different trophic ecologies and dietary preferences. Only by combining information from acoustics, trawling, genetics, and local fishermen, were the identity, abundance, and the vertical and horizontal distribution of the physonect siphonophore, N. cara, established.

Description: The work was funded by the Ministry of Fisheries and Coastal Affairs through the Institute of Marine Research (IMR), while the Research Council of Norway (RCN) is thanked for the financial support through the project The Arctic Ocean Ecosystem—(SI_ARCTIC, RCN 228896). AH was supported by the Norwegian Taxonony Initiative (NTI 70184233) and ForBio Research School funding (RCN 248799 and NTI 70184215).

Description: Author(s): Matthew Reichert, Hugo Defienne, and Jason W. Fleischer Single-photon-sensitive cameras can now be used as massively parallel coincidence counters for entangled photon pairs. This enables measurement of biphoton joint probability distributions with orders-of-magnitude greater dimensionality and faster acquisition speeds than traditional raster scanning o... [Phys. Rev. A 98, 013841] Published Thu Jul 26, 2018

Description: Author(s): Hamid Reza Hamedi, Julius Ruseckas, and Gediminas Juzeliūnas We propose a scheme to exchange optical vortices of slow light using the phenomenon of electromagnetically induced transparency in a four-level double- Λ atom-light coupling scheme illuminated by a pair of probe fields as well as two control fields of larger intensity. We study the light-matter inter... [Phys. Rev. A 98, 013840] Published Thu Jul 26, 2018

Description: Author(s): M. Sotome, N. Kida, S. Horiuchi, and H. Okamoto In noncentrosymmetric media, optical rectification is known to be a general mechanism of the generation of terahertz electromagnetic waves. Here, we show that effective terahertz radiation is possible via a different mechanism in a hydrogen-bonded organic molecular ferroelectric 5,6-dichloro-2-methy... [Phys. Rev. A 98, 013843] Published Thu Jul 26, 2018

Description: Author(s): E. S. Efimenko, S. A. Sychugin, M. V. Tsarev, and M. I. Bakunov It was recently predicted [M. I. Bakunov, A. V. Maslov, and M. V. Tsarev, Phys. Rev. A 95 , 063817 (2017) ] that simultaneous optical rectification and multiphoton absorption of an ultrashort laser pulse in an electro-optic crystal can generate a quasistatic electromagnetic precursor propagating ahead... [Phys. Rev. A 98, 013842] Published Thu Jul 26, 2018

Description: Author(s): Andrea Armaroli, Patrice Féron, and Yannick Dumeige We consider self-pulsing regimes in chains of Kerr nonlinear optical microresonators. By means of a supermodal diagonalization procedure of the conventional coupled-mode theory in time, we theoretically and numerically study the bifurcation diagrams of a singly pumped three-cavity and a doubly pumpe... [Phys. Rev. A 98, 013848] Published Fri Jul 27, 2018

Description: Author(s): Zhexin Zhao, Yu Shi, Kaifeng Chen, and Shanhui Fan An in-depth theoretical analysis of optical antennas is presented. The study is not only helpful for the understanding of fundamental questions, such as the subtleties of reciprocity between the absorption and emission processes of emitters coupled with optical antennas, but it may also contribute to better design antennas for a given application. [Phys. Rev. A 98, 013845] Published Fri Jul 27, 2018

Description: Author(s): Peter A. Ivanov, Fabian Letscher, Jonathan Simon, and Michael Fleischhauer Recently, the creation of a strong magnetic field in a photonic cavity system has been demonstrated [N. Schine et al. , Nature (London) 534 , 671 (2016) .]. Using this setup, we propose a scheme to adiabatically transfer flux quanta simultaneously to all cavity photons. The flux transfer is achieved u... [Phys. Rev. A 98, 013847] Published Fri Jul 27, 2018

Description: Author(s): Rozenn Diehl, Erik Hebestreit, René Reimann, Felix Tebbenjohanns, Martin Frimmer, and Lukas Novotny Optomechanical control of a levitated nanoparticle at subwavelength distances from an interface is demonstrated. The advances in terms of force sensitivity and positioning are relevant for the characterization of short-range interactions, such as Casimir forces, and for building on-chip levitated-optomechanical devices, among others. [Phys. Rev. A 98, 013851] Published Mon Jul 30, 2018

Description: Author(s): Avner Peleg and Debananda Chakraborty We study transmission stabilization against radiation emission and enhancement of transmission quality in soliton-based nonlinear optical waveguides with weak linear gain-loss, cubic loss, and delayed Raman response. We show by numerical simulations with perturbed nonlinear Schrödinger propagation m... [Phys. Rev. A 98, 013853] Published Mon Jul 30, 2018

Description: Author(s): Giuseppe Fiscelli, Lucia Rizzuto, and Roberto Passante We consider the energy transfer process between two identical atoms placed inside a perfectly conducting cylindrical waveguide. We first introduce a general analytical expression of the energy transfer amplitude in terms of the electromagnetic Green's tensor; we then evaluate it in the case of a cyl... [Phys. Rev. A 98, 013849] Published Mon Jul 30, 2018

Description: Author(s): Aline Pham, Airong Zhao, Cyriaque Genet, and Aurélien Drezet Efforts to improve enantioselective detection of chiral molecules have initiated great interest in the fields of chiral light and chiral plasmonics. While superchiral light had been reported as highly sensitive enantiomer probes, optical response of chiral molecules can also be boosted at the vicini... [Phys. Rev. A 98, 013837] Published Tue Jul 24, 2018

Description: Author(s): V. G. Arkhipkin and S. A. Myslivets We propose and analyze an efficient scheme for the one- and two-dimensional atomic gratings based on periodic spatial modulation of the Raman gain and dispersion, which we name the Raman-induced diffraction gratings (RIDGs). There are fundamentally different from those based on electromagnetically i... [Phys. Rev. A 98, 013838] Published Tue Jul 24, 2018

Description: Author(s): Chang-Sheng Hu, Zhen-Biao Yang, Huaizhi Wu, Yong Li, and Shi-Biao Zheng We investigate the dynamics of an optomechanical system where a cavity with a movable mirror involves a degenerate optical parametric amplifier and is driven by a periodically modulated laser field. Our results show that the cooperation between the parametric driving and periodically modulated cavit... [Phys. Rev. A 98, 023807] Published Mon Aug 06, 2018

Description: Author(s): J. Petráček and V. Kuzmiak We studied numerically the effect of disorder on the propagation of the channel plasmon polaritons (CPP) in arrays of evanescently coupled rectangular grooves cut into the planar surface of metal in contact with vacuum or a dielectric medium. The grooves are assumed to be of the same width and depth... [Phys. Rev. A 98, 023806] Published Mon Aug 06, 2018

Description: Author(s): B. X. Wang and C. Y. Zhao We study the topological optical states in one-dimensional dimerized ultracold atomic chains, as an extension of the Su-Schrieffer-Heeger (SSH) model. By taking the fully retarded near-field and far-field dipole-dipole interactions into account, we describe the system by an effective non-Hermitian H... [Phys. Rev. A 98, 023808] Published Mon Aug 06, 2018

Description: Author(s): A. W. Chin, E. Mangaud, O. Atabek, and M. Desouter-Lecomte Engineering and harnessing coherent excitonic transport in organic nanostructures has recently been suggested as a promising way towards improving manmade light-harvesting materials. However, realizing and testing the dissipative system-environment models underlying these proposals is presently very... [Phys. Rev. A 97, 063823] Published Tue Jun 12, 2018

Description: Author(s): Xianxin Guo, Yefeng Mei, and Shengwang Du We report the demonstration of a configurable coherent quantum-memory-based beam splitter (BS) for a single-photon wave packet making use of laser-cooled Rb 85 atoms and electromagnetically induced transparency. The single-photon wave packet is converted (stored) into a collective atomic spin state a... [Phys. Rev. A 97, 063805] Published Tue Jun 05, 2018

Description: Author(s): Fabio Pistolesi It has been recently proposed that single molecule spectroscopy could be employed to detect the motion of nanomechanical resonators. Estimates of the coupling constant ( g ) between the molecular two-level system and the oscillator indicate that it can reach values much larger than the mechanical reso... [Phys. Rev. A 97, 063833] Published Fri Jun 15, 2018

Description: Author(s): V. Savinov Emission of electromagnetic radiation by accelerated particles with electric, toroidal, and anapole dipole moments is analyzed. It is shown that ellipticity of the emitted light can be used to differentiate between electric and toroidal dipole sources and that anapoles, elementary neutral nonradiati... [Phys. Rev. A 97, 063834] Published Fri Jun 15, 2018

Description: Author(s): Arnab Chakrabarti and Rangeet Bhattacharyya We report an alternate formulation of the quantum master equation (QME) to describe the dynamics of a quantum system weakly coupled to a heat bath, in the presence of weak external driving. A key feature of this approach is the introduction of an explicit Hamiltonian to model the thermal fluctuation... [Phys. Rev. A 97, 063837] Published Mon Jun 18, 2018

Description: Author(s): Chengzhi Qin, Luqi Yuan, Bing Wang, Shanhui Fan, and Peixiang Lu Here we create an effective electric field force for photon in a synthetic frequency lattice to control the spectrum of light. The frequency lattice is created based on an optical waveguide modulator in which the dynamic index modulation can induce photonic transitions between adjacent lattice sites... [Phys. Rev. A 97, 063838] Published Mon Jun 18, 2018

Description: Author(s): Alisée Nguyen, Pedro González de Alaiza Martínez, Illia Thiele, Stefan Skupin, and Luc Bergé We study terahertz (THz) emission by two-color femtosecond filaments in air using pump wavelengths λ 0 from 0.8 to 10.6 μ m . Comprehensive three-dimensional numerical simulations show that tens-of-centimeter long filaments created by a 10.6- μ m pump pulse can produce mJ energy yields and GV/m field str... [Phys. Rev. A 97, 063839] Published Mon Jun 18, 2018

Description: Author(s): Xiyun Li, Wenjie Nie, Aixi Chen, and Yueheng Lan We propose theoretically a four-mode coupled optomechanical system to explore the optical-response properties of an optical trimer system consisting of a passive cavity, a no-loss-gain cavity, and an active cavity coupled with a mechanical oscillator. In the study, the passive cavity is driven by an... [Phys. Rev. A 98, 053848] Published Tue Nov 27, 2018

Description: Author(s): Mario A. Beltran and David M. Paganin We study generalized dark-field imaging systems. These are a subset of linear shift-invariant optical imaging systems that exhibit arbitrary aberrations and for which normally incident plane-wave input yields zero output. We write down the theory for the forward problem of imaging coherent scalar op... [Phys. Rev. A 98, 053849] Published Tue Nov 27, 2018

Description: Author(s): Simone Felicetti, Myung-Joong Hwang, and Alexandre Le Boité We present a circuit-QED scheme which makes it possible to reach the ultrastrong-coupling regime of a nondipolar interaction between a single qubit and a quantum resonator. We show that the system Hamiltonian is well approximated by a two-photon quantum Rabi model and propose a simple scattering exp... [Phys. Rev. A 98, 053859] Published Thu Nov 29, 2018

Description: Author(s): A. S. Samsonov, E. N. Nerush, and I. Yu. Kostyukov We study electron motion in electromagnetic (EM) fields in the radiation-dominated regime. It is shown that the electron trajectories become close to some asymptotic trajectories in the strong-field limit. The description of the electron dynamics by these asymptotic trajectories significantly differ... [Phys. Rev. A 98, 053858] Published Thu Nov 29, 2018

Description: Author(s): S. Anguiano, P. Sesin, A. E. Bruchhausen, F. R. Lamberti, I. Favero, M. Esmann, I. Sagnes, A. Lemaître, N. D. Lanzillotti-Kimura, P. Senellart, and A. Fainstein Semiconductor pillar microcavities have recently emerged as a promising optomechanical platform in the unprecedented 20-GHz frequency range. Currently established models for the mechanical behavior of micropillars, however, rely on complete numerical simulations or semianalytical approaches, which m... [Phys. Rev. A 98, 063810] Published Thu Dec 06, 2018

Description: Author(s): V. I. Kruglov and J. D. Harvey An exact solitary wave solution is presented for the nonlinear Schrödinger equation governing the propagation of pulses in optical fibers including the effects of second-, third-, and fourth-order dispersions. The stability of this solitonlike solution with a sech 2 shape is proven. The main criteria... [Phys. Rev. A 98, 063811] Published Fri Dec 07, 2018

Description: Author(s): C. Wurl and H. Fehske The inelastic scattering and conversion process between photons and phonons by laser-driven quantum dots is analyzed for a honeycomb array of optomechanical cells. Using Floquet theory for an effective two-level system, we solve the related time-dependent scattering problem, beyond the standard rota... [Phys. Rev. A 98, 063812] Published Fri Dec 07, 2018

Description: Author(s): Andrey B. Matsko and Sergey P. Vyatchanin We find that the measurement sensitivity of an optical integrating gyroscope is fundamentally limited due to ponderomotive action of the light leading to the standard quantum limit of the rotation angle detection. The uncorrelated quantum fluctuations of power of clockwise and counterclockwise elect... [Phys. Rev. A 98, 063821] Published Thu Dec 13, 2018

Description: Author(s): M. V. Fedorov, A. A. Sysoeva, S. V. Vintskevich, and D. A. Grigoriev We consider regimes of spontaneous parametric down-conversion, both noncollinear and nondegenerate in frequencies. Parameters characterizing degrees of noncollinearity and of nondegeneracy are defined, and they are shown to be not independent of each other. At a given degree of nondegeneracy the emi... [Phys. Rev. A 98, 013850] Published Mon Jul 30, 2018

Description: Author(s): Ming Li, Chang-Ling Zou, Chun-Hua Dong, Xi-Feng Ren, and Dao-Xin Dai Optical microcavities are often used to realize enhanced nonlinear optical interactions for highly efficient second-harmonic generation. With increased pump power, the efficiency of nonlinear frequency conversion can be increased further, whereas some other unwanted nonlinear effects will also emerg... [Phys. Rev. A 98, 013854] Published Mon Jul 30, 2018

Description: Author(s): Suyesh Koyu and Timur V. Tscherbul We explore the coherent dynamics of a three-level V -type system interacting with a thermal bath in the regime where thermal excitation occurs much faster than spontaneous decay. We present analytic solutions of the Bloch-Redfield quantum master equations, which show that strong incoherent pumping ca... [Phys. Rev. A 98, 023811] Published Tue Aug 07, 2018

Description: Author(s): Ronen Chriki, Simon Mahler, Chene Tradonsky, Vishwa Pal, Asher A. Friesem, and Nir Davidson Spatial coherence quantifies spatial field correlations and is one of the fundamental properties of light. Here we investigate the spatial coherence of highly multimode lasers in the regime of short timescales. Counterintuitively, we show that in this regime, the temporal (longitudinal) modes play a... [Phys. Rev. A 98, 023812] Published Tue Aug 07, 2018

Description: Author(s): Urszula A. Laudyn, Michał Kwaśny, Mirosław A. Karpierz, Noel F. Smyth, and Gaetano Assanto We demonstrate that reorientational spatial solitons can curve when propagating in a medium with engineered walk-off along the direction of propagation. In this regard, we employ nematic liquid crystals with molecular anchoring defined by electron-beam lithography and optic axis distribution modulat... [Phys. Rev. A 98, 023810] Published Tue Aug 07, 2018

Description: Author(s): Luis F. Muñoz-Martínez, Felippe Alexandre Silva Barbosa, Antônio Sales Coelho, Luis Ortiz-Gutiérrez, Marcelo Martinelli, Paulo Nussenzveig, and Alessandro S. Villar Researchers have entangled six modes of a laser cavity—a record number for such a device. [Phys. Rev. A 98, 023823] Published Mon Aug 13, 2018

Description: Author(s): M. Ahumada, P. A. Orellana, and J. C. Retamal We report the formation of bound states in the continuum in a whispering gallery resonator coupled to a one-dimensional waveguide. We find that an incident photon wave packet is partially stored in the bound state in the continuum due to a roughness-induced symmetry breaking. We discuss quantum inte... [Phys. Rev. A 98, 023827] Published Mon Aug 13, 2018

Description: Author(s): D. Arsenović, M. M. Ćurčić, T. Khalifa, B. Zlatković, Ž. Nikitović, I. S. Radojičić, A. J. Krmpot, and B. M. Jelenković We experimentally and theoretically study propagation of 80-ns Gaussian-like probe pulses in hot potassium vapor under conditions of four-wave mixing (FWM). The atomic scheme for FWM is off-resonant, double- Λ atomic scheme, with pump and probe photons, mediated in the K vapor, generating new probe a... [Phys. Rev. A 98, 023829] Published Tue Aug 14, 2018

Description: Author(s): Qian Jiang, Qingmei Hu, Bingsuo Zou, and Yongyou Zhang We design a single microwave photon switch through a one-dimensional waveguide coupled with a side Jaynes-Cummings system, namely, a single-mode cavity with an embedded Rydberg atom Rb 87 . Since the energy spectra of the Rb 87 atom depend on the electrostatic field, the Rb 87 atom can couple with the c... [Phys. Rev. A 98, 023830] Published Wed Aug 15, 2018

Description: Author(s): Ryan O. Behunin, Nils T. Otterstrom, Peter T. Rakich, Sarat Gundavarapu, and Daniel J. Blumenthal The dynamics of cascaded-order Brillouin lasers make them ideal for applications such as rotation sensing, highly coherent optical communications, and low-noise microwave signal synthesis. Remarkably, when implemented at the chip scale, recent experimental studies have revealed that Brillouin lasers... [Phys. Rev. A 98, 023832] Published Fri Aug 17, 2018

Description: Author(s): A. V. Yulin The interactions of optical solitons with dispersive waves of low intensity in optical fibers with high-order dispersion are considered numerically and analytically. It is shown that Cherenkov phase matching between the solitons and the dispersive waves makes it possible to achieve an efficient inte... [Phys. Rev. A 98, 023833] Published Fri Aug 17, 2018

Description: Author(s): Dashiell L. P. Vitullo, M. G. Raymer, B. J. Smith, Michał Karpiński, L. Mejling, and K. Rottwitt Photonic time-frequency entanglement is a promising resource for quantum information processing technologies. We investigate swapping of continuous-variable entanglement in the time-frequency degree of freedom using three-wave mixing in the low-gain regime with the aim of producing heralded biphoton... [Phys. Rev. A 98, 023836] Published Mon Aug 20, 2018

Description: Author(s): P. A. Kalozoumis, G. Theocharis, V. Achilleos, S. Félix, O. Richoux, and V. Pagneux Topological edge modes in one-dimensional photonic systems are usually studied considering the interface between two different semi-infinite periodic crystals (PCs) with inverted band structure around the Dirac point. Here we consider the case where the two PCs are finite, constituting an open scatt... [Phys. Rev. A 98, 023838] Published Mon Aug 20, 2018

Description: Author(s): Ievgen I. Arkhipov We present an experimental method for complete identification of the nonclassicality of Gaussian states in the whole phase space. Our method relies on nonclassicality witnesses written in terms of measured integrated intensity moments up to the third order, provided that appropriate local coherent d... [Phys. Rev. A 98, 021803(R)] Published Tue Aug 21, 2018

Description: Author(s): Alex O. C. Davis, Valérian Thiel, Michał Karpiński, and Brian J. Smith The ability to characterize the complete quantum state of light is essential for both fundamental and applied science. For single photons the quantum state is provided by the mode that it occupies. The spectral temporal mode structure of light has recently emerged as an essential means for quantum i... [Phys. Rev. A 98, 023840] Published Tue Aug 21, 2018

Description: Author(s): Todd Van Mechelen and Zubin Jacob Topological phases of matter arise in distinct fermionic and bosonic flavors. The fundamental differences between them are encapsulated in their rotational symmetries—the spin. Although spin quantization is routinely encountered in fermionic topological edge states, analogous quantization for bosons... [Phys. Rev. A 98, 023842] Published Tue Aug 21, 2018

Description: Author(s): N. R. Bernier, L. D. Tóth, A. K. Feofanov, and T. J. Kippenberg Level repulsion—the opening of a gap between two degenerate modes due to coupling—is ubiquitous anywhere from solid-state theory to quantum chemistry. In contrast, if one mode has negative energy, the mode frequencies attract instead. They converge and develop imaginary components, leading to an ins... [Phys. Rev. A 98, 023841] Published Tue Aug 21, 2018

Description: Author(s): Ievgen I. Arkhipov In a recent paper [I. I. Arkhipov, Phys. Rev. A 98 , 021803 (2018) ], it was shown that one can completely identify the nonclassicality of single- and two-mode Gaussian states by means of certain nonclassicality witnesses which are based on intensity moments up to the third order of optical fields, pr... [Phys. Rev. A 98, 023839] Published Tue Aug 21, 2018

Description: Author(s): Kevin A. Fischer, Rahul Trivedi, and Daniil Lukin In this work, we discuss connections between different theoretical physics communities and their works, all related to systems that act as sources of particles such as photons, phonons, or electrons. Our interest is to understand how a low-dimensional quantum system driven by coherent fields, e.g., ... [Phys. Rev. A 98, 023853] Published Tue Aug 28, 2018

Description: Author(s): P. Nalbach and V. Leyton We derive a Magnus expansion for a frequency chirped quantum two-level system. We obtain a time-independent effective Hamiltonian which generates a stroboscopic time evolution. At lowest order the according dynamics is identical to results from using a rotating wave approximation. We determine, furt... [Phys. Rev. A 98, 023855] Published Tue Aug 28, 2018

Description: Author(s): David Barral, Kamel Bencheikh, Virginia D'Auria, Sébastien Tanzilli, Nadia Belabas, and Juan Ariel Levenson In a recent paper [Barral et al. , Phys. Rev. A 96 , 053822 (2017) ], we proposed a strategy to generate bipartite and quadripartite continuous-variable entanglement of bright quantum states based on degenerate down-conversion in a pair of evanescently coupled nonlinear χ ( 2 ) waveguides. Here, we show ... [Phys. Rev. A 98, 023857] Published Wed Aug 29, 2018

Description: Author(s): Kai Li, Hao Fu, and Yong Li We propose a theoretical method of detection of angular velocity based on a two-mode mechanical resonator placed on a rotating platform. The Coriolis force induced by rotation provides the coupling between the two intrinsic mechanical modes, which oscillate along two orthogonal directions perpendicu... [Phys. Rev. A 98, 023862] Published Thu Aug 30, 2018

Description: Author(s): Qing Sun, Jie Hu, Lin Wen, Han Pu, and An-Chun Ji We consider two spin-1/2 fermions inside an optical cavity which supports a single-mode quantized light field. We demonstrate that the atom-light coupling (ALC) gives rise to the two-atom polariton states, where the two atoms are highly entangled with cavity photons. We focus on the case where the c... [Phys. Rev. A 98, 033801] Published Tue Sep 04, 2018

Description: Author(s): Sheng-Jun Yang, Jun Rui, Han-Ning Dai, Xian-Min Jin, Shuai Chen, and Jian-Wei Pan Quantum interface of coherent optical field and atomic excitations plays an important role in quantum metrology and quantum information science. The electromagnetically-induced-transparency (EIT) technique has shown versatile and powerful capability in many applications during the last decades. By u... [Phys. Rev. A 98, 033802] Published Tue Sep 04, 2018

Description: Author(s): A. Patas, M. Matthews, S. Hermelin, J. Gateau, J. Kasparian, J. P. Wolf, and A. Lindinger In this paper we examine the spectral changes in a white light laser filament due to different pulse shapes generated by a pulse-shaping setup. We particularly explore how the properties of the filament spectra can be controlled by parametrically tailored white light pulses. The experiments are carr... [Phys. Rev. A 98, 033804] Published Thu Sep 06, 2018

Description: Author(s): V. S. Shchesnovich and M. E. O. Bezerra We introduce collective geometric phases of bosons and fermions interfering on a linear unitary multiport, where each phase depends on the internal states of identical particles (i.e., not affected by the multiport) and corresponds to a cycle of the symmetric group. We show that quantum interference... [Phys. Rev. A 98, 033805] Published Thu Sep 06, 2018

Description: Author(s): Aritra Banerjee and Samudra Roy We study the interaction of a copropagating finite-energy Airy pulse and a soliton in a Kerr medium under third-order dispersion. It is observed that a strong radiation appears when a self-accelerating Airy pulse collides with a delayed soliton in time domain. We confirm both analytically and numeri... [Phys. Rev. A 98, 033806] Published Fri Sep 07, 2018

Description: Author(s): Katarina Stensson and Gunnar Björk A detailed analysis and recipe for measuring intensity correlation are provided and experimentally verified. The scheme allows the characterization of quantum light sources in the multiphoton regime. [Phys. Rev. A 98, 033812] Published Mon Sep 10, 2018

Description: Author(s): Yufang Hao, Jiayin Shen, and Jianhong Ruan Separation of the spin and orbital angular momenta of the electromagnetic field has been discussed frequently in recent years. The spin and orbital angular momenta cannot be made simultaneously gauge invariant and Lorentz covariant and are not conserved separately. After analyzing the source of the ... [Phys. Rev. A 98, 033809] Published Mon Sep 10, 2018

Description: Author(s): Xu-Lin Zhang and C. T. Chan Hybrid exceptional points (HEPs) are non-Hermitian degeneracies that exhibit different dispersion relations (e.g., linear or square-root) along different directions in the parameter space. Here, we show that a two-state system consisting of coupled ferromagnetic waveguides applied with a bias magnet... [Phys. Rev. A 98, 033810] Published Mon Sep 10, 2018

Description: Author(s): Mikko Partanen and Jukka Tulkki Light propagating in a nondispersive medium is accompanied by a mass density wave (MDW) of atoms set in motion by the optical force of the field itself [ Phys. Rev. A 95 , 063850 (2017) ]. This recent result is in strong contrast with the approximation of fixed atoms, which assumes that atoms are fixed... [Phys. Rev. A 98, 033813] Published Tue Sep 11, 2018

Description: Author(s): Alexander Hause, Christoph Mahnke, and Fedor Mitschke The impact of power loss on fiber-optic solitons and soliton compounds has regained interest recently, as coding schemes employing inverse scattering eigenvalues are being discussed. Loss lifts the integrability of the underlying nonlinear Schrödinger equation and has usually been treated by perturb... [Phys. Rev. A 98, 033814] Published Wed Sep 12, 2018

Description: Author(s): R. A. Brewster, T. B. Pittman, and J. D. Franson Loss and decoherence are major problems in the transmission of nonclassical states of light over large distances. It was recently shown that the effects of decoherence can be reduced by applying a probabilistic noiseless attenuator before transmitting a quantum state through a lossy channel, followe... [Phys. Rev. A 98, 033818] Published Fri Sep 14, 2018

Description: Author(s): Y. F. Han, C. J. Zhu, X. S. Huang, and Y. P. Yang We present a proposal to control and improve the nonclassicality of photons in a single-atom cavity-QED system with a strong coupling strength, where the atom is directly driven by external fields. Exploring the eigenvalues and the corresponding eigenstates of the system, we show that the dressed st... [Phys. Rev. A 98, 033828] Published Thu Sep 27, 2018

Description: Author(s): Elisha S. Matekole, Hwang Lee, and Jonathan P. Dowling We study the atom-vapor-based photon-number-resolving detection from first principles, including quantum-mechanical treatment of the electromagnetic field. We study a photon detector model that combines coherently controlled absorption of light and resonance fluorescence to achieve photon counting a... [Phys. Rev. A 98, 033829] Published Fri Sep 28, 2018

Description: Author(s): R. Grimaudo, A. S. M. de Castro, M. Kuś, and A. Messina An exact analytical treatment of the dynamical problem for time-dependent 2 × 2 pseudo-Hermitian su ( 1 , 1 ) Hamiltonians is reported. A class of exactly solvable and physically transparent scenarios are identified within both classical and quantum contexts. The class is spanned by a positive parameter ν ... [Phys. Rev. A 98, 033835] Published Fri Sep 28, 2018

Description: Author(s): Ehsan Saei Ghareh Naz, Ion Cosma Fulga, Libo Ma, Oliver G. Schmidt, and Jeroen van den Brink We design a setup to realize tunable topological phases in elastic photonic crystals. Using the Su-Schrieffer-Heeger (SSH) model as a canonical example, we show how a system can be continuously tuned across its topological phase transition by stretching. We examine the setup both analytically and nu... [Phys. Rev. A 98, 033830] Published Fri Sep 28, 2018

Description: Author(s): X. Y. Zhang, Y. H. Zhou, Y. Q. Guo, and X. X. Yi We explore the optomechanically induced transparency (OMIT) in a parity-time-symmetric ( PT -symmetric) optomechanical system (OMS) in which the mechanical oscillator is coupled to another one via the Coulomb interaction. Calculating the transmission rate of the probe field, we find that double optome... [Phys. Rev. A 98, 033832] Published Fri Sep 28, 2018

Description: Author(s): Deshui Yu, Leong Chuan Kwek, Luigi Amico, and Rainer Dumke We theoretically explore the applications of a nonlinear circuit QED system, where a charge qubit is inductively coupled to an LC resonator, in the photonic engineering and ultrastrong-coupling multiphoton quantum optics. An arbitrary Fock-state pulsed maser, where the artificial qubit plays the gai... [Phys. Rev. A 98, 033833] Published Fri Sep 28, 2018

Description: Author(s): Lin Zschiedrich, Felix Binkowski, Niko Nikolay, Oliver Benson, Günter Kewes, and Sven Burger We introduce a theory to analyze the behavior of light emitters in nanostructured environments rigorously. Based on spectral theory, the approach opens the possibility to quantify precisely how an emitter decays to resonant states of the structure and how it couples to a background, also in the pres... [Phys. Rev. A 98, 043806] Published Wed Oct 03, 2018

Description: Author(s): M. Eslami, N. H. Khiavi, R. Kheradmand, and F. Prati It has recently been shown that vertical-cavity surface-emitting lasers with an intracavity saturable absorber are capable of forming binary localized structures called twin laser cavity solitons (LCSs). Apart from their asymmetric intensity distribution, they can spontaneously rotate about their ce... [Phys. Rev. A 98, 043807] Published Wed Oct 03, 2018

Description: Author(s): Sankar Davuluri and Yong Li By using electromagnetically induced transparency phenomena (EIT) in three-level atoms, we propose an interferometry technique for measuring constant classical force. The classical force is estimated by measuring the momentum, which is quantum nondemolition observable in this scheme, of the atoms. U... [Phys. Rev. A 98, 043809] Published Thu Oct 04, 2018

Description: Author(s): G. G. Kozlov, I. I. Ryzhov, A. Tzimis, Z. Hatzopoulos, P. G. Savvidis, A. V. Kavokin, M. Bayer, and V. S. Zapasskii We consider polarization properties of the unpolarized emission of an ensemble of classical emitters with randomly varying polarization. The light is supposed to be unpolarized in the sense that all three polarization-related components of its Stokes vector are zero. At the same time, the mean-squar... [Phys. Rev. A 98, 043810] Published Fri Oct 05, 2018

Description: Author(s): Abdulrahim Al Balushi, Wan Cong, and Robert B. Mann An open question in experimental physics is the characterization of gravitational effects in quantum regimes. We propose an experimental setup that uses well-tested techniques in cavity optomechanics to observe the effects of the gravitational interaction between two micromechanical oscillators on t... [Phys. Rev. A 98, 043811] Published Fri Oct 05, 2018

Description: Author(s): Xinyun Cui, Zhihai Wang, and Yong Li In this paper, we propose a theoretical scheme to detect the emitter-resonator coupling strength in the ultra-strong-coupling regime in the quantum Rabi model via introducing an auxiliary resonator. We demonstrate the total system as a two-mode Rabi model and obtain the ground state by the transform... [Phys. Rev. A 98, 043812] Published Fri Oct 05, 2018

Description: Author(s): Nicolás Quesada and Agata M. Brańczyk Many nonlinear optical technologies require the two-mode spectral amplitude function that describes them—the joint spectral amplitude (JSA)—to be separable. We prove that the JSA factorizes only when the incident pump field and phase-matching function are Gaussian functions. We show this by mapping ... [Phys. Rev. A 98, 043813] Published Fri Oct 05, 2018