Gauge Invariant Formulation and Bosonisation of the Schwinger Model

The functional integral of the massless Schwinger model in $(1+1)$ dimensions is reduced to an integral in terms of local gauge invariant quantities. It turns out that this approach leads to a natural bosonisation scheme, yielding, in particular the famous `bosonisation rule'' and giving some deeper insight into the nature of the bosonisation phenomenon. As an application, the chiral anomaly is calculated within this formulation.Comment: LaTeX, 8 page

SL(2)×R+SL(2)\times\mathbb{R}^+ Exceptional Field Theory: An Action for F-Theory

Exceptional Field Theory employs an extended spacetime to make supergravity fully covariant under the U-duality groups of M-theory. The 12-dimensional EFT associated to the group $SL(2)\times\mathbb{R}^+$ together with its action is presented. Demanding the closure of the algebra of local symmetries leads to a constraint, known as the section condition, that must be imposed on all fields. This constraint has two inequivalent solutions, one giving rise to 11-dimensional supergravity and the other leading to Type IIB supergravity and F-theory. Thus $SL(2)\times\mathbb{R}^+$ Exceptional Field Theory contains both F-theory and M-theory in a single 12-dimensional formalism.Comment: Proceedings prepared for the "Workshop on Geometry and Physics", November 2016, Ringberg Castle, Germany, v.2: references added, published in PoS CORFU2016 (2017

Automatic software for controlling cryogenic systems

A technical discussion of the lessons learned during the seven years of software development/testing which occurred on the Liquid Oxygen System for the Space Shuttle at the Kennedy Space Center is given. Problems which were solved during these years came into four distinct phases: design/debug before simulation runs, verification using simulation with models up through Space Transportation System-1 launch, hardware usage from first launch to Space Transportation System-5 launch, and future use. Each problem/solution describes the apparent problem requirements/constraints, usable alternatives, selected action, and results

Charge Superselection Sectors for Scalar QED on the Lattice

The lattice model of scalar quantum electrodynamics (Maxwell field coupled to a complex scalar field) in the Hamiltonian framework is discussed. It is shown that the algebra of observables ${\cal O}({\Lambda})$ of this model is a $C^*$-algebra, generated by a set of gauge-invariant elements satisfying the Gauss law and some additional relations. Next, the faithful, irreducible and non-degenerate representations of ${\cal O}({\Lambda})$ are found. They are labeled by the value of the total electric charge, leading to a decomposition of the physical Hilbert space into charge superselection sectors. In the Appendices we give a unified description of spinorial and scalar quantum electrodynamics and, as a byproduct, we present an interesting example of weakly commuting operators, which do not commute strongly