On Nonlocal Modified Gravity and Cosmology

Despite many nice properties and numerous achievements, general relativity is not a complete theory. One of actual approaches towards more complete theory of gravity is its nonlocal modification. We present here a brief review of nonlocal gravity with its cosmological solutions. In particular, we pay special attention to two nonlocal models and their nonsingular bounce solutions for the cosmic scale factor.Comment: 11 pages, Published in Springer Proceedings in Mathematics & Statistics 111 (2014) 251-26

Academic/industry innovations for sustainable building design and refurbishment

Development and efficient dissemination of innovations for sustainable building design and refurbishment are crucial for the competitiveness of companies operating in the construction sector which faces pressure to reduce levels of carbon emissions from existing and new buildings to zero. An overwhelming majority of companies operating in the construction sector in Scotland are small to medium size enterprises (SMEs) who do not have sufficient resources in the current economic downturn to undertake research in building design, products and processes that will make buildings more sustainable. A joint project of seven Scottish universities has been initiated to support collaboration with small to medium sized enterprises in developing and disseminating innovation for sustainable building design and refurbishment. The project concept and methods used for efficient dissemination of the project outputs to SMEs across Scotland are explained. An analysis of the outputs of completed feasibility studies and the provision of academic consultancy through the project indicates the range of problems tackled as well as trends in the development and use of innovations for a more sustainable built environment in Scotland

Pairing instabilities of Dirac composite fermions

Recently, a Dirac (particle-hole symmetric) description of composite fermions in the half-filled quantum Hall system was proposed [D. T. Son, Phys. Rev. X 5, 031027 (2015)], and we study its possible consequences on BCS (Cooper) pairing of composite fermions (CF's). One of the main consequences is the existence of anisotropic states in single and bilayer systems, which was previously suggested in Ref. [J. S. Jeong and K. Park, Phys. Rev. B 91, 195119 (2015)]. We argue that in the half-filled single layer the gapped states may sustain anisotropy, because isotropic pairings may coexist with anisotropic ones. Furthermore, anisotropic pairings with addition of a particle-hole (PH) symmetry breaking mass term may evolve into rotationally symmetric states, i.e. Pfaffian states of Halperin-Lee-Read (HLR) ordinary CF's. On the basis of the Dirac formalism, we argue that in the quantum Hall bilayer at total filling one, with decreasing distance between layers weak pairing of p-wave paired CF's is gradually transformed from Dirac to ordinary, HLR-like, with concomitant decrease in the CF number. Global characterization of low-energy spectrum based on the Dirac CF's agrees well with previous calculations performed by exact diagonalization on a torus. Finally, we discuss features of Dirac formalism when applied in this context.Comment: 8 pages, no figures, published versio

Some Cosmological Solutions of a Nonlocal Modified Gravity

We consider nonlocal modification of the Einstein theory of gravity in framework of the pseudo-Riemannian geometry. The nonlocal term has the form $\mathcal{H}(R) \mathcal{F}(\Box)\mathcal {G}(R)$, where $\mathcal{H}$ and $\mathcal{G}$ are differentiable functions of the scalar curvature $R,$ and $\mathcal{F}(\Box)= \displaystyle \sum_{n =0}^{\infty} f_{n}\Box^{n}$ is an analytic function of the d'Alambert operator $\Box .$ Using calculus of variations of the action functional, we derived the corresponding equations of motion. The variation of action is induced by variation of the gravitational field, which is the metric tensor $g_{\mu\nu}$. Cosmological solutions are found for the case when the Ricci scalar $R$ is constant.Comment: 10 page