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39 results on '"Avraham, Eran"'

1. 2d duality for orthogonal gauge theories with 8 supersymmetries

Author

Avraham, Eran and Bergman, Oren

Subjects
High Energy Physics - Theory
Abstract

We recently conjectured a set of dualities relating two-dimensional orthogonal gauge theories with $\mathcal{N}=(4,4)$ supersymmetry, analogous to Hori's dualities with $\mathcal{N}=(2,2)$ supersymmetry. Here we provide a quantitative test of this conjecture by computing the elliptic genera of the dual pairs and showing that they agree. The elliptic genus of orthogonal gauge theories has multiple topological sectors that depend on the global structure of the group and on the value of a discrete $\theta$ parameter. We derive the dependence on the $\theta$ parameter by determining whether a given sector has $(S)Pin$ structure or not., Comment: 17 pages

Published
2019
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2. A note on D0-branes and instantons in 5d supersymmetric gauge theories

Author

Avraham, Eran and Bergman, Oren

Subjects
High Energy Physics - Theory
Abstract

We refine a previous proposal for obtaining the multi-instanton partition function from the supersymmetric index of the 1d supersymmetric gauge theory on the worldline of D0-branes. We provide examples where the refinements are crucial for obtaining the correct result., Comment: 30 pages, 6 figures. Typos corrected

Published
2018
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3. Branes and 2d N=(2,2) gauge theories with orthogonal and symplectic groups

Author

Bergman, Oren and Avraham, Eran

Subjects
High Energy Physics - Theory
Abstract

We construct two-dimensional N=(2,2) supersymmetric gauge theories with orthogonal and symplectic groups using branes and orientifold planes in Type IIA string theory. A number of puzzles regarding the construction, including the effect of exchanging NS5-branes on an orientifold 2-plane, are resolved by lifting the configurations to M theory. The low energy properties and conjectured dualities of these theories are reproduced in the M-brane description. A similar construction of N=(4,4) theories with orthogonal and symplectic groups leads to new duality conjectures for these theories., Comment: 22 pages, 27 figures. Type IIA linking number computation corrected in section 4.5. Clarified and expanded the discussion of N=(4,4) dualities in section 5. References added

Published
2018
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9. Canonical structure of higher derivative theories

Author

Avraham, Eran and Brustein, Ram

Subjects
High Energy Physics - Theory, Quantum Physics
Abstract

The canonical structure of theories whose Lagrangian contains higher powers of time derivatives is often obscured by the nonlinear relationship between the velocities and momenta. We use the Dirac formalism and define a generalized Legendre transform to overcome some of the difficulties associated with inverting the relation between velocities and momenta. We are then able to define a standard single valued symplectic structure on phase space and a compatible single valued Hamiltonian. We demonstrate the application of our formalism in several examples., Comment: 19 pages, 2 figures, v2 typos corrected, some references and clarifications added, replaced to agree with published version

Published
2014
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26. Branes and 2d N = (2; 2) gauge theories with orthogonal and symplectic groups.

Author

Bergman, Oren and Avraham, Eran

Subjects
BRANES, SUPERSYMMETRY, GAUGE field theory, WEIL conjectures, ORTHOGONAL decompositions
Abstract

We construct two-dimensional N = (2; 2) supersymmetric gauge theories with orthogonal and symplectic groups using branes and orientifold planes in Type IIA string theory. A number of puzzles regarding the construction, including the effect of exchanging NS5-branes on an orientifold 2-plane, are resolved by lifting the configurations to M theory. The low energy properties and conjectured dualities of these theories are reproduced in the M-brane description. A similar construction of N = (4; 4) theories with orthogonal and symplectic groups leads to new duality conjectures for these theories. [ABSTRACT FROM AUTHOR]

Published
2018
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38. Several Basic and Practical Aspects Related to Electrochemical Deionization of Water.

Author

Bouhadana, Yaniv, Avraham, Eran, Soffer, Abraham, and Aurbach, Doron

Subjects
SALINE water conversion, CARBON electrodes, SALT, DRINKING water, ELECTRODES
Abstract

The article examines water desalination through electrosorption of ions onto activated carbon electrodes or capacitive deionization (CDI). It is stated that feasible production of drinking water from salty water solutions by CDI may be limited to solutions with a few thousands parts per million (ppm) of sodium chloride (NaCl). The potential of simple components of cells for CDI should reportedly be based on maximal deionization efficiency and not the widest possible reaction.

Published
2010
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39. Developing Ion Electroadsorption Stereoselectivity, by Pore Size Adjustment with Chemical Vapor Deposition onto Active Carbon Fiber Electrodes. Case of Ca2/NaSeparation in Water Capacitive Desalination

Author

Avraham, Eran, Yaniv, Bouhadana, Soffer, Abraham, and Aurbach, Doron

Abstract

By using carbon chemical vapor deposition (CVD) onto active porous carbon fibers, we were able to reduce the pore size of the active carbon to obtain selective carbon molecular sieves (CMS) of variable properties. The pore size of these carbons was characterized by the adsorption of molecules of different dimensions (molecular probe adsorption) from the gas phase. By manipulating the several experimental parameters of the CVD process, the pore size of the CMS could be finely tuned to fall between sizes of alkaline earth cations (Ca2; Mg2, 6−7 Å in diameter), and the much smaller size of hydrated monovalent cations (4 Å in diameter). This was proven by voltammetric measurements of the pore-tailored carbon electrodes in the corresponding salt solutions, which also provided a measure of the differential capacity of the electrical double layer (EDL) vs the potential (e.g., at potentials negative to the potential of the zero charge, the EDL capacity was very small for CaCl2and MgCl2solutions, while it was high for NaCl solutions). The CVD process applied herein did not significantly reduce the specific surface area and the pore volume of the carbons. This implies that the carbon deposits are only superficial and that the pore blocking effect takes place only at the pore mouth. Hence, the adsorption processes related to these carbons involve surface barrier mechanisms. The importance of the selectivity thus obtained relates to a possible use of these carbon electrodes in electrochemical water desalination processes. By using these carbons as electrodes in capacitive water deionization processes, it is possible to selectively remove Nacations, leaving Ca2and Mg2ions (which are important nutrients) in the treated water.

Published
2008
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