Surface core excitons in III-V semiconductors

Recent experiments have shown that the cation core excitons on the (110) surface of many III-V semiconductors have very large binding energies.(^1) They are sometimes reported to be bound by as much as ≳0.8 eV, tightly bound compared to bulk binding energies of ≾0.1 eV. To explore this phenomenon, we have calculated the binding energies and oscillator strengths of core excitons on the (110) surface of GaAs, GaSb, GaP, and InP

Quantum phase diagrams of fermionic dipolar gases for an arbitrary orientation of dipole moment in a planar array of 1D tubes

We systematically study ground state properties of fermionic dipolar gases in a planar array of one-dimensional potential tubes for an arbitrary orientation of dipole moments. Using the Luttinger liquid theory with the generalized Bogoliubov transformation, we calculate the elementary excitations and the Luttinger scaling exponents for various relevant quantum orders. The complete quantum phase diagrams for arbitrary polar angle of the dipole moment is obtained, including charge density wave, p-wave superfluid, inter-tube gauge-phase density wave, and inter-tube s-wave superfluid, where the last two breaks the U(1) gauge symmetry of the system (conservation of particle number in each tube) and occurs only when the inter-tube interaction is larger than the intra-tube interaction. We then discuss the physical properties of these many-body phases and their relationship with some solid state systems.Comment: 10 pages and 10 figure

Interaction-induced first order correlation between spatially-separated 1D dipolar fermions

We calculate the ground-state properties of fermionic dipolar atoms or molecules in a one-dimensional double-tube potential by using the Luttinger liquid theory and the density matrix renormalization-group calculation. When the external field is applied near a magic angle with respect to the double-tube plane, the long-ranged dipolar interaction can generate a spontaneous correlation between fermions in different tubes, even when the bare intertube tunneling rate is negligibly small. Such interaction-induced correlation strongly enhances the contrast of the interference fringes and therefore can be easily observed in the standard time-of-flight experiment.Comment: Same as the published versio

Angular Forces Around Transition Metals in Biomolecules

Quantum-mechanical analysis based on an exact sum rule is used to extract an semiclassical angle-dependent energy function for transition metal ions in biomolecules. The angular dependence is simple but different from existing classical potentials. Comparison of predicted energies with a computer-generated database shows that the semiclassical energy function is remarkably accurate, and that its angular dependence is optimal.Comment: Tex file plus 4 postscript figure

A Multiscale Approach to Determination of Thermal Properties and Changes in Free Energy: Application to Reconstruction of Dislocations in Silicon

We introduce an approach to exploit the existence of multiple levels of description of a physical system to radically accelerate the determination of thermodynamic quantities. We first give a proof of principle of the method using two empirical interatomic potential functions. We then apply the technique to feed information from an interatomic potential into otherwise inaccessible quantum mechanical tight-binding calculations of the reconstruction of partial dislocations in silicon at finite temperature. With this approach, comprehensive ab initio studies at finite temperature will now be possible.Comment: 5 pages, 3 figure

Revisiting the relationships between human well-being and ecosystems in dynamic social-ecological systems: Implications for stewardship and development

This is the final version. Available from Cambridge University Press via the DOI in this record.Non-technical summary We argue that the ways in which we as humans derive well-being from nature - for example by harvesting firewood, selling fish or enjoying natural beauty - feed back into how we behave towards the environment. This feedback is mediated by institutions (rules, regulations) and by individual capacities to act. Understanding these relationships can guide better interventions for sustainably improving well-being and alleviating poverty. However, more attention needs to be paid to how experience-related benefits from nature influence attitudes and actions towards the environment, and how these relationships can be reflected in more environmentally sustainable development projects. Technical summary In the broad literatures that address the linked challenge of maintaining ecosystem integrity while addressing poverty and inequality, there is still a need to investigate how linkages and feedbacks between ecosystem services and well-being can be taken into account to ensure environmental sustainability and improved livelihoods. We present a conceptual model towards a dynamic and reciprocal understanding of the feedbacks between human well-being and ecosystems. The conceptual model highlights three mechanisms through which people derive benefits from ecosystems (use, money and experience), and illustrates how these benefits can affect values, attitudes and actions towards ecosystems. Institutions and agency determine access to and distribution of benefits and costs, and also present barriers or enabling factors for individual or collective action. The conceptual model synthesises insights from existing but mostly separate bodies of literature on well-being and the benefits humans derive from ecosystems, and reveals gaps and areas for future research. Two case studies illustrate how recognizing the full feedback loop between how ecosystems support human well-being and how people behave towards those ecosystems, as well as intervention points within the loop, can guide better action for sustainable poverty alleviation and stewardship of the biosphere.Swedish Research CouncilSwedish Research Counci