Gravitational Decoherence and the Possibility of Its Interferometric Detection.

We present a general master equation describing the quantum dynamics of a scalar bosonic field interacting with an external weak and stochastic gravitational field. The dynamics predicts decoherence both in position and in energy momentum. We show how the master equation reproduces, thus generalizing, the previous results in the literature by taking appropriate limits. We estimate the effect of gravitational decoherence in atom interferometers, providing also a straightforward way to assess the magnitude of the effect.

Impact of Dynamical Collapse Models on Inflationary Cosmology.

Inflation solves several cosmological problems at the classical and quantum level, with a strong agreement between the theoretical predictions of well-motivated inflationary models and observations. In this Letter, we study the corrections induced by dynamical collapse models, which phenomenologically solve the quantum measurement problem, to the power spectrum of the comoving curvature perturbation during inflation and the radiation-dominated era. We find that the corrections are strongly negligible for the reference values of the collapse parameters.

The efficacy of etodolac and ibuprofen, regarding gender, on pain, edema and trismus after impacted lower third molar surgery: A randomized prospective clinical split-mouth study.

BACKGROUND: This study aimed to conduct a randomized prospective study about the efficacy of etodolac and ibuprofen on trismus, pain and edema regarding gender of patients submitted to impacted lower third molar teeth extraction. MATERIAL AND METHODS: Thirty patients aging between 16 and 35 year-old were submitted to the exodontia of impacted lower third molars. During the postoperative period, patients received nine ibuprofen (600 mg) or etodolac (300 mg) pills via oral administration immediately after surgery and repeated doses every eight hours during three days. Patients were evaluated regarding pain, trismus and edema. RESULTS: Sixteen men and fourteen women participated of the study. No statistical difference was established regarding gender according to the evaluated parameters. However, etodolac use showed better results regarding pain, trismus and edema. CONCLUSIONS: Pain, edema and trismus after impacted third molars extraction were not influenced by gender.

Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors.

Despite the unquestionable empirical success of quantum theory, witnessed by the recent uprising of quantum technologies, the debate on how to reconcile the theory with the macroscopic classical world is still open. Spontaneous collapse models are one of the few testable solutions so far proposed. In particular, the continuous spontaneous localization (CSL) model has become subject of intense experimental research. Experiments looking for the universal force noise predicted by CSL in ultrasensitive mechanical resonators have recently set the strongest unambiguous bounds on CSL. Further improving these experiments by direct reduction of mechanical noise is technically challenging. Here, we implement a recently proposed alternative strategy that aims at enhancing the CSL noise by exploiting a multilayer test mass attached on a high quality factor microcantilever. The test mass is specifically designed to enhance the effect of CSL noise at the characteristic length r_{c}=10^{-7} m. The measurements are in good agreement with pure thermal motion for temperatures down to 100 mK. From the absence of excess noise, we infer a new bound on the collapse rate at the characteristic length r_{c}=10^{-7} m, which improves over previous mechanical experiments by more than 1 order of magnitude. Our results explicitly challenge a well-motivated region of the CSL parameter space proposed by Adler.

Novel time-resolved camera based on compressed sensing.

Time-resolved cameras with high temporal resolution (down to ps) enable a huge set of novel applications ranging from biomedicine and environmental science to material and device characterization. In this work, we propose, and experimentally validate, a novel detection scheme for time-resolved imaging based on a compressed sampling approach. The proposed scheme unifies into a single element all the required operations, i.e. space modulation, space integration and time-resolved detection, paving the way to dramatic cost reduction, performance improvement and ease of use.

Improved Noninterferometric Test of Collapse Models Using Ultracold Cantilevers.

Spontaneous collapse models predict that a weak force noise acts on any mechanical system, as a consequence of the collapse of the wave function. Significant upper limits on the collapse rate have been recently inferred from precision mechanical experiments, such as ultracold cantilevers and the space mission LISA Pathfinder. Here, we report new results from an experiment based on a high-Q cantilever cooled to millikelvin temperatures, which is potentially able to improve the current bounds on the continuous spontaneous localization (CSL) model by 1 order of magnitude. High accuracy measurements of the cantilever thermal fluctuations reveal a nonthermal force noise of unknown origin. This excess noise is compatible with the CSL heating predicted by Adler. Several physical mechanisms able to explain the observed noise have been ruled out.

Exploring synergies between transit investment and dense redevelopment: a scenario analysis in a rapidly urbanizing landscape.

Like many urban areas around the world, Durham and Orange counties in North Carolina, USA are experiencing population growth and sprawl that is putting stress on the transportation system. Light rail and denser transit-oriented development are being considered as possible solutions. However, local agencies and stakeholders are concerned the light rail may worsen housing affordability and have questioned whether investment in both light rail and dense redevelopment are necessary to achieve community goals. We developed an integrated system dynamics model to quantitatively explore the outcomes of these land use and transportation options across multiple societal dimensions. The model incorporates feedbacks among the land, transportation, economic, equity, and energy sectors. This paper uses the results of four model scenarios, run between 2000 and 2040, to address two main questions: (1) what role does redevelopment play in capturing the socioeconomic benefits of transit infrastructure investment? And (2) how do redevelopment and light-rail transit interact to affect housing and transportation affordability? We find that transit investment and dense redevelopment combine synergistically to better achieve the goals of the light-rail line, including economic development, mobility, and compact growth. However, housing affordability does worsen in the combined scenario, as transportation-cost savings are not sufficient to offset the rise in housing costs. We emphasize that model users may input their own assumptions to explore the dynamics of alternative scenarios. We demonstrate how spatially-aggregated systems models can complement traditional land use and transportation models in the regional planning process.

Upper Bounds on Spontaneous Wave-Function Collapse Models Using Millikelvin-Cooled Nanocantilevers.

Collapse models predict a tiny violation of energy conservation, as a consequence of the spontaneous collapse of the wave function. This property allows us to set experimental bounds on their parameters. We consider an ultrasoft magnetically tipped nanocantilever cooled to millikelvin temperature. The thermal noise of the cantilever fundamental mode has been accurately estimated in the range 0.03-1 K, and any other excess noise is found to be negligible within the experimental uncertainty. From the measured data and the cantilever geometry, we estimate the upper bound on the continuous spontaneous localization collapse rate in a wide range of the correlation length r_{C}. Our upper bound improves significantly previous constraints for r_{C}>10^{-6} m, and partially excludes the enhanced collapse rate suggested by Adler. We discuss future improvements.

Pulsed laser deposition of two-dimensional ZnO nanocrystals on Au(111): growth, surface structure and electronic properties.

Two-dimensional (2D) ZnO structures have been deposited on the Au(111) surface by means of the pulsed laser deposition technique. In situ scanning tunneling microscopy and scanning tunneling spectroscopy measurements have been performed to characterize morphological, structural and electronic properties of 2D ZnO at the nanoscale. Starting from a sub-monolayer coverage, we investigated the growth of ZnO, identifying different atomic layers (up to the fifth). At low coverage, we observed single- and bi-layer nanocrystals, characterized by a surface moiré pattern that is associated to a graphene-like ZnO structure. By increasing the coverage, we revealed a morphological change starting from the fourth layer, which was attributed to a transition toward a bulk-like structure. Investigation of the electronic properties revealed the semiconducting character of 2D ZnO. We observed a dependence of the density of states (DOS) and, in particular, of the conduction band (CB) on the ZnO thickness, with a decreasing of the CB onset energy for increasing thickness. The CB DOS of 2D ZnO shows a step-like behaviour which may be interpreted as due to a 2D quantum confinement effect in ZnO atomic layers.