Precision Measurement of Time-Reversal Symmetry Violation with Laser-Cooled Polyatomic Molecules

Precision searches for time-reversal symmetry violating interactions in polar molecules are extremely sensitive probes of high energy physics beyond the Standard Model. To extend the reach of these probes into the PeV regime, long coherence times and large count rates are necessary. Recent advances in laser cooling of polar molecules offer one important tool -- optical trapping. However, the types of molecules that have been laser-cooled so far do not have the highly desirable combination of features for new physics searches, such as the ability to fully polarize and the existence of internal co-magnetometer states. We show that by utilizing the internal degrees of freedom present only in molecules with at least three atoms, these features can be attained simultaneously with molecules that have simple structure and are amenable to laser cooling and trapping

Two dimensional foam rheology with viscous drag

We formulate and apply a continuum model that incorporates elasticity, yield stress, plasticity and viscous drag. It is motivated by the two-dimensional foam rheology experiments of Debregeas et al. [G. Debregeas, H. Tabuteau, and J.-M. di Meglio, Phys. Rev. Lett. 87, 178305 (2001)] and Wang et al [Y. Wang, K. Krishan, and M. Dennin, Phys. Rev. E 73, 031401 (2006)], and is successful in exhibiting their principal features an exponentially decaying velocity profile and strain localisation. Transient effects are also identified.Comment: accepted version (to appear in PRL). Some parts of the paper have been rewritten (mainly introduction and final discussion

The SLS-Berlin: Validation of a German Computer-Based Screening Test to Measure Reading Proficiency in Early and Late Adulthood

Reading proficiency, i.e., successfully integrating early word-based information and utilizing this information in later processes of sentence and text comprehension, and its assessment is subject to extensive research. However, screening tests for German adults across the life span are basically non-existent. Therefore, the present article introduces a standardized computerized sentence-based screening measure for German adult readers to assess reading proficiency including norm data from 2,148 participants covering an age range from 16 to 88 years. The test was developed in accordance with the children’s version of the Salzburger LeseScreening (SLS, Wimmer and Mayringer, 2014). The SLS-Berlin has a high reliability and can easily be implemented in any research setting using German language. We present a detailed description of the test and report the distribution of SLS-Berlin scores for the norm sample as well as for two subsamples of younger (below 60 years) and older adults (60 and older). For all three samples, we conducted regression analyses to investigate the relationship between sentence characteristics and SLS-Berlin scores. In a second validation study, SLS-Berlin scores were compared with two (pseudo)word reading tests, a test measuring attention and processing speed and eye-movements recorded during expository text reading. Our results confirm the SLS-Berlin’s sensitivity to capture early word decoding and later text related comprehension processes. The test distinguished very well between skilled and less skilled readers and also within less skilled readers and is therefore a powerful and efficient screening test for German adults to assess interindividual levels of reading proficiency

Processing of parafoveally presented words. An fMRI study.

Abstract The present fMRI study investigated neural correlates of parafoveal preprocessing during reading and the type of information that is accessible from the upcoming - not yet fixated - word. Participants performed a lexical decision flanker task while the constraints imposed by the first three letters (the initial trigram) of parafoveally presented words were controlled. Behavioral results evidenced that the amount of information extracted from parafoveal stimuli, was affected by the difficulty of the foveal stimulus. Easy to process foveal stimuli (i.e., high frequency nouns) allowed parafoveal information to be extracted up to the lexical level. Conversely, when foveal stimuli were difficult to process (orthographically legal nonwords) only constraining trigrams modulated the task performance. Neuroimaging findings showed no effects of lexicality (i.e., difference between words and pseudowords) in the parafovea independently from the difficulty of the foveal stimulus. The constraints imposed by the initial trigrams, however, modulated the hemodynamic response in the left supramarginal gyrus. We interpreted the supramarginal activation as reflecting sublexical (phonological) processes. The missing parafoveal lexicality effect was discussed in relation to findings of experiments which observed effects of parafoveal semantic congruency on electrophysiological correlates

Syntactic presentations for glued toposes and for crystalline toposes

We regard a geometric theory classified by a topos as a syntactic presentation for the topos and develop tools for finding such presentations. Extensions (or expansions) of geometric theories, which can not only add axioms but also symbols and sorts, are treated as objects in their own right, to be able to build up complex theories from parts. The role of equivalence extensions, which leave the theory the same up to Morita equivalence, is investigated. Motivated by the question what the big Zariski topos of a non-affine scheme classifies, we show how to construct a syntactic presentation for a topos if syntactic presentations for a covering family of open subtoposes are given. For this, we introduce a transformation of theory extensions such that when the result, dubbed a conditional extension, is added to a theory, it requires part of the data a model is made of only under some condition given in the form of a closed geometric formula. We also give a general definition for systems of interdependent theory extensions, to be able to talk about compatible syntactic presentations not only for the open subtoposes in a given cover but also for their finite intersections. An important concept for finding classified theories of toposes in concrete situations is that of theories of presheaf type. We develop several techniques for extending a theory while preserving the presheaf type property, and give a list of examples of simple extensions which can destroy it. Finally, we determine a syntactic presentation of the big crystalline topos of a scheme. In the case of an affine scheme, this is accomplished by showing that the biggest part of the classified theory is of presheaf type and transforming the site defining the crystalline topos into the canonical presheaf site for this theory, while the remaining axioms induce the Zariski topology. Then we can apply our results on gluing classifying toposes to obtain a classified theory even in the non-affine case

Sweeping molecules with light

Many areas of physics—precision measurements, quantum information, and physical chemistry, to name a few—are starting to benefit from the enormous advantages offered by cold and ultracold polar molecules. Molecules have more states, more interactions, and more chemical properties compared to atoms, which make them exciting to study but difficult to tame. In particular, the powerful techniques of atomic laser cooling cannot be naïvely applied to molecules due to their complicated structure. Developments over the past few years have made directly laser cooled and trapped molecules a reality, and now much effort is focused on making these samples larger, denser, and colder—an important step to realizing many of their exciting applications. A careful experimental and numerical study by Truppe et al (2017 New J. Phys. 19 022001) demonstrates a significant improvement and advance in understanding of one of the most limiting steps in laser cooling and trapping of molecules—slowing them from a molecular beam to a near-standstill, with small enough kinetic energy that they can be loaded into a trap

Trapped Ions Test Fundamental Particle Physics

New precision experiments using trapped molecular ions provide an alternative method for determining if the electron has an electric dipole moment