Asymmetries Between Strange and Antistrange Particle Production in Pion-Proton Interactions

Recent measurements of the asymmetries between Feynman $x$ distributions of strange and antistrange hadrons in $\pi^- A$ interactions show a strong effect as a function of $x_F$. We calculate strange hadron production in the context of the intrinsic model and make predictions for particle/antiparticle asymmetries in these interactions.Comment: version to be published in Nucl. Phys. A, 46 pages LaTeX, 15 .eps figure

Quantum-enhanced gyroscopy with rotating anisotropic Bose–Einstein condensates

High-precision gyroscopes are a key component of inertial navigation systems. By considering matter wave gyroscopes that make use of entanglement it should be possible to gain some advantages in terms of sensitivity, size, and resources used over unentangled optical systems. In this paper we consider the details of such a quantum-enhanced atom interferometry scheme based on atoms trapped in a carefully-chosen rotating trap. We consider all the steps: entanglement generation, phase imprinting, and read-out of the signal and show that quantum enhancement should be possible in principle. While the improvement in performance over equivalent unentangled schemes is small, our feasibility study opens the door to further developments and improvements

The ABCDEFGs of Entomology

As a parent of three kids, I love finding ways to spark their curiosity and love for learning, so combining my interest in entomology and my experience as a parent, I came up with a fun yet informative book about insects. I selected the most common insects kids might encounter daily at home, school, or while playing at the park: ants, butterflies, cockroaches, dragonflies, earwigs, flies, and grasshoppers. I aimed to develop an activity book that anyone could use, whether they are a teacher or a parent without a scientific background. By focusing on these seven specific insects, I wanted to showcase their incredible features, like anatomy, flight capabilities, and feeding behaviors. Despite their small size and many challenges, insects thrive with impressive strengths, and only by understanding their world can we appreciate their significance and value in our lives. Ultimately, I hope that more kids and adults will be inspired to explore the outdoors and appreciate the wonders of insects. If we respect and protect their habitats, we can help ensure a brighter future for ourselves. Includes: Why are insects important and What is an insect? Sections on ants, butterflies, cockroaches, dragonflies, earwigs, flies, and grasshoppers, and activities for each A glossary and a list of media and reference

Relative sea-level rise and the development of channel-fill and shallow-water sequences on Cape Cod, Massachusetts

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution January 1999Channel-fill sediments located in shallow-water off the south shore of Cape Cod, Massachusetts, provide a record of the late-Pleistocene and Holocene geological evolution in a post-glacial setting. Though conventionally difficult to sample adequately and anticipated to have low preservation potential, channel-fill sequences record in some detail differing relative sea-level and sedimentation processes. Two distinct channel-fill sequences record differing sequence stratigraphies, and hence different origins and post glacial histories. These sequences have accumulated in channels eroded into two different late-Pleistocene glacial units. The first fill-type was encountered in channels on the upper portions of the channel network in northern half of the study site. Channels in this portion of the channel system were incised into the late-Pleistocene glacial outwash substrate by spring sapping Uchupi and Oldale, 1994. The channel-fill sequences are comprised of a transgressive systems tract composed of a consistent sequence of coastal embayment and shoreline facies that have succeeded one another in response to Holocene relative sea-level rise. As relative sea-level flooded these paleo-channels, marsh environments were established in response to rising relative sea-level. With continued sea-level rise, the marsh environments migrated farther up channel. The exposed paleo-channels continued to flood, accommodating quiet water coastal embayments, likely protected from wave action by barrier beaches located more seaward. As relative sea-level rise continued, the coastline was driven landward over regions within the paleo-channels that formerly accommodated marsh and embayment sedimentation. The landward migration of the coastline was indicated by beach and barrier facies that covered the fine grained coastal embayment sediments. With further relative sea-level rise, beach and barrier settings were eroded as the shoreface migrated farther landward and nearshore marine deposition by wave and tidal flows ensued. Sedimentary environments similar to those recorded in the channels are found in modern coastal embayments on the south shore of Cape Cod. The second channel-fill type, which forms part of the southern and western portion of the channel network is more difficult to relate to the previously described sequence. The channels that contain fill were not adequately defined in this survey but were probably incised during the late-Pleistocene in response to ice melting and retreat. The sediments that make up this channel-fill are composed mainly of late-Pleistocene glaciolacustrine silts and clays. Sediments that make up the Holocene transgressive systems tract are limited to the upper meter of this channel sequence. They are composed of two sand units that reflect Holocene beach and nearshore sedimentation. The absence of coastal embayment and other paralic facies from the systems tract suggests that these channels did not accommodate protected embayments or that these sediments were not well preserved during the submergence of this region. Changes in the channel orientation or in the rate of relative sea-level rise may have contributed to this difference in sediment fill.While conducting this research the author was partially supported as a National Science Foundation Coastal Trainee WHOI # 85412900. Funding from the Andrew W. Mellon Foundation WHOI # 25903900 and the Woods Hole Oceanographic Institution Education Office WHOI # 45050 also supported this work

Bethe-Salpeter bound-state structure in Minkowski space

The quantitative investigation of the scalar Bethe-Salpeter equation in Minkowski space, within the ladder-approximation framework, is extended to include the excited states. This study has been carried out for an interacting system composed by two massive bosons exchanging a massive scalar, by adopting (i) the Nakanishi integral representation of the Bethe-Salpeter amplitude, and (ii) the formally exact projection onto the null plane. Our analysis, on one hand, confirms the reliability of the method already applied to the ground state and, on the other one, extends the investigation from the valence distribution in momentum space to the corresponding quantity in the impact-parameter space, pointing out some relevant features, like (i) the equivalence between Minkowski and Euclidean transverse-momentum amplitudes, and (ii) the leading exponential fall-off of the valence wave function in the impact-parameter space.Comment: 15 pages, 7 figure

Experimental Study of the Role of Atomic Interactions on Quantum Transport

We report an experimental study of quantum transport for atoms confined in a periodic potential and compare between thermal and BEC initial conditions. We observe ballistic transport for all values of well depth and initial conditions, and the measured expansion velocity for thermal atoms is in excellent agreement with a single-particle model. For weak wells, the expansion of the BEC is also in excellent agreement with single-particle theory, using an effective temperature. We observe a crossover to a new regime for the BEC case as the well depth is increased, indicating the importance of interactions on quantum transport.Comment: 4 pages, 3 figure