Hidden Charge 2e Boson in Doped Mott Insulators: Field Theory of Mottness

We construct the low energy theory of a doped Mott insulator, such as the high-temperature superconductors, by explicitly integrating over the degrees of freedom far away from the chemical potential. For either hole or electron doping, a charge 2e bosonic field emerges at low energy. The charge 2e boson mediates dynamical spectral weight transfer across the Mott gap and creates a new charge e excitation by binding a hole. The result is a bifurcation of the electron dispersion below the chemical potential as observed recently in angle-resolved photoemission on Pb-doped Bi_2Sr_2CaCu_2O_{8+\delta} (Pb2212).Comment: 4 pages, 2 figures: Correct version to appear in PRL. Revisions include a derivation of the electron operator at low energies which reveals a branching structure seen recently in ARPES on Pb221

Functional Analysis ofDrosophilaand Mammalian Cut Proteins in Flies

AbstractThecutlocus acts as a bimodal switch controlling cell fate in the peripheral nervous system ofDrosophilaand is also required for the development of the wing margin. It encodes a protein, Cut, that contains an atypical homeodomain and three copies of a new motif which can bind DNAin vitro.The human protein CDP and the murine protein Cux have recently been isolated as DNA-binding activities and they are structurally related to Cut. We show that ectopic expression of Cut, CDP, or Cux similarly affects embryonic sensory organ development and can rescue a wing scalloping mutant phenotype associated with loss ofcutexpression along the prospective wing margins. This suggests that the function of Cut is evolutionarily conserved

Exact Integration of the High Energy Scale in Doped Mott Insulators

We expand on our earlier work (cond-mat/0612130, Phys. Rev. Lett. {\bf 99}, 46404 (2007)) in which we constructed the exact low-energy theory of a doped Mott insulator by explicitly integrating (rather than projecting) out the degrees of freedom far away from the chemical potential. The exact low-energy theory contains degrees of freedom that cannot be obtained from projective schemes. In particular a new charge $\pm 2e$ bosonic field emerges at low energies that is not made out of elemental excitations. Such a field accounts for dynamical spectral weight transfer across the Mott gap. At half-filling, we show that two such excitations emerge which play a crucial role in preserving the Luttinger surface along which the single-particle Green function vanishes. In addition, the interactions with the bosonic fields defeat the artificial local SU(2) symmetry that is present in the Heisenberg model. We also apply this method to the Anderson-U impurity and show that in addition to the Kondo interaction, bosonic degrees of freedom appear as well. Finally, we show that as a result of the bosonic degree of freedom, the electron at low energies is in a linear superposition of two excitations--one arising from the standard projection into the low-energy sector and the other from the binding of a hole and the boson.Comment: Published veriso

Do’s and Don’ts in Arctic Research? An interactive Workshop on Community-based Research with Early Career Scientists

Research in Arctic and Sub-Arctic environments presents unique challenges and obstacles, in particular, establishing a necessary baseline understanding of environmental systems in the face of ongoing climate change. Pairing scientific and traditional knowledge approaches can help to close this gap, however creating a bridge between non-local, non-indigenous research scientists and traditional knowledge holders in northern communities can be challenging. For example, most researchers are likely less familiar with local norms, customs, as well as with social systems and protocols, leading to inevitable challenges for the scientists and communities. In a cross-cutting initiative for the International Arctic Science Committee (IASC), Fellows of different the Terrestrial, Cryosphere and Marine Working Groups organized a workshop session on “Community-based Research: Do`s and Don`ts of Arctic Research” during the Young Researchers Workshop at the 11th International Conference on Permafrost in Potsdam, Germany, June 2016. This workshop brought together Early Career Scientists (ECS, including engineers) with resident Arctic representatives and experts to discuss best practices in the exchange of traditional and modern knowledge when conducting research in northern communities. After a short presentation by the panelists, ECSs with invited experts split into small groups with an IASC Fellow as moderator. The break-out groups discussed their experiences and raised questions for the invited experts. These discussions generated a list of “do’s and don’ts” from each group, which were presented and discussed with the larger audiences. The format and organization of the workshop allowed an interactive and fruitful discussion, generating a diverse list of Arctic Research considerations and best practices. Key ideas from the workshop discussions are visualized in the word cloud figure. Recommendations from this workshop included enhancing future support opportunities, like the IASC cross-cutting initiative, to facilitate continued discussions between scientists and northern representatives to maximize the benefits of pairing traditional and modern knowledge to face future challenges

Multicoated composites of nano silicon and graphene nanoplatelets as anodes in Li-ion batteries

A simple, non-vacuum aerosol-assisted chemical deposition (AACD) method was developed for the deposition of a homogeneous composite film of graphene nanoplatelets and nano silicon. The multicoated composite anode (with 10 wt% silicon) exhibited promising capacity retention of 85.8% after 500 discharge/charge cycles in Li-ion batteries

Vaccines for protecting infants from bacterial causes of diarrheal disease

The global diarrheal disease burden fo