Connection between rotation and miscibility in a two-component Bose-Einstein condensate

A two-component Bose-Einstein condensate rotating in a toroidal trap is investigated. The topological constraint depends on the density distribution of each component along the circumference of the torus, and therefore the quantization condition on the circulation can be controlled by changing the miscibility using the Feshbach resonance. We find that the system exhibits a variety of dynamics depending on the initial angular momentum when the miscibility is changed.Comment: 6 pages, 7 figure

Electrodynamic trapping of spinless neutral atoms with an atom chip

Three dimensional electrodynamic trapping of neutral atoms has been demonstrated. By applying time-varying inhomogeneous electric fields with micron-sized electrodes, nearly $10^2$ strontium atoms in the $^1S_0$ state have been trapped with a lifetime of 80 ms. In order to design the electrodes, we numerically analyzed the electric field and simulated atomic trajectories in the trap, which showed reasonable agreement with the experiment.Comment: 4pages, 4figures, to appear in Phys. Rev. Let

Analytical Tachyonic Lump Solutions in Open Superstring Field Theory

We construct a classical solution in the GSO(-) sector in the framework of a Wess-Zumino-Witten-like open superstring field theory on a non-BPS D-brane. We use an su(2) supercurrent, which is obtained by compactifying a direction to a circle with the critical radius, in order to get analytical tachyonic lump solutions to the equation of motion. By investigating the action expanded around a solution we find that it represents a deformation from a non-BPS D-brane to a D-brane-anti-D-brane system at the critical value of a parameter which is contained in classical solutions. Although such a process was discussed in terms of boundary conformal field theory before, our study is based on open superstring field theory including interaction terms.Comment: 17 pages, references adde

Spin observables in the pn→pΛpn \to p \Lambda reaction

The T matrix of the LambdaN-> NN reaction, which is a strangeness changing weak process, is derived. The explicit formulas of the spin observables are given for s-wave p-Lambda final states which kinematically corresponds to inverse reaction of the weak nonmesonic decay of Lambda hypernuclei. One can study interferences between amplitudes of parity- conserving and violating, spin- singlet and triplet and isospin- singlet and triplet. Most of them are not available in the study of the nonmesonic decay. They clarify structure of the reaction and constrain strongly theoretical models for weak hyperon nucleon interaction.Comment: 7pages,ReVTeX,no figure

Coherent transfer of photoassociated molecules into the rovibrational ground state

We report on the direct conversion of laser-cooled 41K and 87Rb atoms into ultracold 41K87Rb molecules in the rovibrational ground state via photoassociation followed by stimulated Raman adiabatic passage. High-resolution spectroscopy based on the coherent transfer revealed the hyperfine structure of weakly bound molecules in an unexplored region. Our results show that a rovibrationally pure sample of ultracold ground-state molecules is achieved via the all-optical association of laser-cooled atoms, opening possibilities to coherently manipulate a wide variety of molecules.Comment: 4 pages, 4 figure

Effective strategies for multi-sectoral research using large-scale models

Large-scale integrated assessment models (IAMs) have become critical knowledge objects and tools for global-scope simulation of energy, economic, engineering, and environmental systems. IAMs are widely used in assessment of climate change mitigation (for instance, within the IPCC) and other Sustainable Development Goals (SDGs). In order to sharpen the relevance of insights from large-scale modeling, researchers often link them into multi-model frameworks together with detailed sectoral (sub-)models of, for instance, transport and mobility; the building stock; critical materials; or water use—or with models of narrower scope (e.g. national or sub-national) but finer resolution. These links capture feedbacks and interactions that may strongly shape transitions to comprehensive sustainability. This presentation begins with current expectations that guide IAM-based research. In particular, it is no longer satisfactory that individual models and 1-to-1 frameworks can analyse, for instance, (a) possible recoveries from the COVID-19 pandemic; (b) the long-term evolution of transport and mobility; and (c) the energy and climate impacts of changing materials flows. Increasingly, stakeholders require assessments that are both integrated *and* highly detailed in multiple sectors/areas such as these. Teams are challenged to produce this knowledge while also progressing in openness, transparency, reproducibility, and validity of research. I argue that meeting these challenges requires systems researchers and modelers to acknowledge that they are engaged in processes of collaborative software development: models are, in an important sense, also complex, long-lived, and evolving pieces of software. This perspective motivates the use of strategies that are common in professional software development, yet woefully underutilized in academia and research: standardization, testing, modularity and reuse, an emphasis on documentation, and iterative workflows with short cycle times. Using the example of the MESSAGEix-GLOBIOM family of models developed by the IIASA Energy, Climate, and Environment (ECE) Program, I demonstrate how adopting best practices of development translates to better science that uses people and resources more efficiently. For instance, the practice of unit-testing code is also a scientific strategy for ensuring internal validity: when code implements research methods, then automated tests ensure that those methods are correct representations of the phenomena represented. This in turn avoids exhausting researchers' time in performing manual validity checks. Next, the practice of modularity entails clearly-defined interfaces: in multi-sectoral or cross-domain integrated assessment frameworks, this is achieved through clear definitions of the background concepts, measures, scales, and system boundaries. Making these items explicit helps researchers see quickly and precisely what translation is required to make (sub-)models interoperable with one another. Finally, sustainability requires the very research processes that support the transition to be equitable and inclusive. I explain how the practices of making software free and open source, writing complete documentation, and continuous development lower barriers to understanding and participating in IAM-based research, especially for those not privileged to work at the few institutions that have the resources to maintain large-scale models. As well, a broad user base translates to a flow of contributions, improved model quality, and ultimately improved perceptions of legitimacy for modeling work

Self-Consistent Velocity Dependent Effective Interactions

The theory of self-consistent effective interactions in nuclei is extended for a system with a velocity dependent mean potential. By means of the field coupling method, we present a general prescription to derive effective interactions which are consistent with the mean potential. For a deformed system with the conventional pairing field, the velocity dependent effective interactions are derived as the multipole pairing interactions in doubly-stretched coordinates. They are applied to the microscopic analysis of the giant dipole resonances (GDR's) of ${}^{148,154}Sm$, the first excited $2^+$ states of Sn isotopes and the first excited $3^-$ states of Mo isotopes. It is clarified that the interactions play crucial roles in describing the splitting and structure of GDR peaks, in restoring the energy weighted sum rule, and in reducing the values of $B(E\lambda)$.Comment: 35 pages, RevTeX, 7 figures (available upon request), to appear in Phys.Rev.

Wedge states in string field theory

The wedge states form an important subalgebra in the string field theory. We review and further investigate their various properties. We find in particular a novel expression for the wedge states, which allows to understand their star products purely algebraically. The method allows also for treating the matter and ghost sectors separately. It turns out, that wedge states with different matter and ghost parts violate the associativity of the algebra. We introduce and study also wedge states with insertions of local operators and show how they are useful for obtaining exact results about convergence of level truncation calculations. These results help to clarify the issue of anomalies related to the identity and some exterior derivations in the string field algebra.Comment: 40 pages, 9 figures, v3: section 3.3 rewritten, few other corrections, set in JHEP styl