Identifying Sneutrino Dark Matter: Interplay between the LHC and Direct Search

Under R-parity, the lightest supersymmetric particle (LSP) is stable and may serve as a good dark matter candidate. The R-parity can be naturally introduced with a gauge origin at TeV scale. We go over why a TeV scale B-L gauge extension of the minimal supersymmetric standard model (MSSM) is one of the most natural, if not demanded, low energy supersymmetric models. In the presence of a TeV scale Abelian gauge symmetry, the (predominantly) right-handed sneutrino LSP can be a good dark matter candidate. Its identification at the LHC is challenging because it does not carry any standard model charge. We show how we can use the correlation between the LHC experiments (dilepton resonance signals) and the direct dark matter search experiments (such as CDMS and XENON) to identify the right-handed sneutrino LSP dark matter in the B-L extended MSSM.Comment: 5 pages, 3 figure

DEVS-based intelligent control of space adapted fluid mixing

The development is described of event-based intelligent control system for a space-adapted mixing process by employing the DEVS (Discrete Event System Specification) formalism. In this control paradigm, the controller expects to receive confirming sensor responses to its control commands within definite time windows determined by its DEVS model of the system under control. The DEVS-based intelligent control paradigm was applied in a space-adapted mixing system capable of supporting the laboratory automation aboard a Space Station

AdS/QHE: Towards a Holographic Description of Quantum Hall Experiments

Transitions among quantum Hall plateaux share a suite of remarkable experimental features, such as semi-circle laws and duality relations, whose accuracy and robustness are difficult to explain directly in terms of the detailed dynamics of the microscopic electrons. They would naturally follow if the low-energy transport properties were governed by an emergent discrete duality group relating the different plateaux, but no explicit examples of interacting systems having such a group are known. Recent progress using the AdS/CFT correspondence has identified examples with similar duality groups, but without the DC ohmic conductivity characteristic of quantum Hall experiments. We use this to propose a simple holographic model for low-energy quantum Hall systems, with a nonzero DC conductivity that automatically exhibits all of the observed consequences of duality, including the existence of the plateaux and the semi-circle transitions between them. The model can be regarded as a strongly coupled analog of the old `composite boson' picture of quantum Hall systems. Non-universal features of the model can be used to test whether it describes actual materials, and we comment on some of these in our proposed model.Comment: LaTex 52 pages 11 figures. Repost improves the discussion of the probe approximation; corrects minor errors; adds references. Second repost generalizes charged solution and improves scaling discussio

Low energy effective theory of Fermi surface coupled with U(1) gauge field in 2+1 dimensions

We study the low energy effective theory for a non-Fermi liquid state in 2+1 dimensions, where a transverse U(1) gauge field is coupled with a patch of Fermi surface with N flavors of fermion in the large N limit. In the low energy limit, quantum corrections are classified according to the genus of the 2d surface on which Feynman diagrams can be drawn without a crossing in a double line representation, and all planar diagrams are important in the leading order. The emerging theory has the similar structure to the four dimensional SU(N) gauge theory in the large N limit. Because of strong quantum fluctuations caused by the abundant low energy excitations near the Fermi surface, low energy fermions remain strongly coupled even in the large N limit. As a result, there are infinitely many quantum corrections that contribute to the leading frequency dependence of the Green's function of fermion on the Fermi surface. On the contrary, the boson self energy is not modified beyond the one-loop level and the theory is stable in the large N limit. The non-perturbative nature of the theory also shows up in correlation functions of gauge invariant operators.Comment: 14 pages, 20 figures; v2) Sec. V on correlation function of gauge invariant operators added; v3) typos corrected, minor changes (to appear in PRB

U(1) Gauge Theory of the Hubbard Model : Spin Liquid States and Possible Application to k-(BEDT-TTF)_2 Cu_2 (CN)_3

We formulate a U(1) gauge theory of the Hubbard model in the slave-rotor representation. From this formalism it is argued that spin liquid phases may exist near the Mott transition in the Hubbard model on triangular and honeycomb lattices at half filling. The organic compound k-(BEDT-TTF)_2 Cu_2 (CN)_3 is a good candidate for the spin liquid state on a triangular lattice. We predict a highly unusual temperature dependence for the thermal conductivity of this material.Comment: 5 pages, 2 figures; paper shortened and the phase diagram of anisotropic triangular lattice correcte

Emergence of gravity from interacting simplices

We consider a statistical model of interacting 4-simplices fluctuating in an N-dimensional target space. We argue that a gravitational theory may arise as a low energy effective theory in a strongly interacting phase where the simplices form clusters with an emergent space and time with the Euclidean signature. In the large N limit, two possible phases are discussed, that is, `gravitational Coulomb phase' and `gravitational Higgs phase'.Comment: 18 pages, 6 figures, one-column format; major revisions in version 5 : reviews on emergent gauge theories added; microscopic simplex model for emergent gravity added; erroneous statements on diffeomorphism invariance remove