Superstring on PP-Wave Orbifold from Large-N Quiver Gauge Theory

We extend the proposal of Berenstein, Maldacena and Nastase to Type IIB superstring propagating on pp-wave over ${\bf R}^4/{\bf Z}_k$ orbifold. We show that first-quantized free string theory is described correctly by the large $N$, fixed gauge coupling limit of ${\cal N}=2$ $[U(N)]^k$ quiver gauge theory. We propose a precise map between gauge theory operators and string states for both untwisted and twisted sectors. We also compute leading-order perturbative correction to the anomalous dimensions of these operators. The result is in agreement with the value deduced from string energy spectrum, thus substantiating our proposed operator-state map.Comment: 11 pages, Late

New aspects of the BMN correspondence beyond the planar limit

Motivated by recent disagreements in the context of AdS/CFT, we study the non-planar sector of the BMN correspondence. In particular, we reconsider the energy shift of states with two stringy excitations in light-cone string field theory and explicitly determine its complete perturbative contribution from the impurity-conserving channel. Surprisingly, our result neither agrees with earlier leading order computations, nor reproduces the gauge theory prediction. More than that, it features half-integer powers of the effective gauge coupling $\lambda'$ representing a qualitative difference to gauge theory. Based on supersymmetry we argue that the above truncation is not suited for conclusive tests of the BMN duality.Comment: 20 pages, 1 figur

An alternative formulation of light-cone string field theory on the plane wave

We construct a manifestly SO(4) x SO(4) invariant, supersymmetric extension of the closed string cubic interaction vertex and dynamical supercharges in light-cone string field theory on the plane wave space-time. We find that the effective vertex for states built out of bosonic creation oscillators coincides with the one previously constructed in the SO(8) formalism and conjecture that in general the two formulations are physically equivalent. Further evidence for this claim is obtained from the discrete Z_2-symmetry of the plane wave and by computing the mass-shift of the simplest stringy state using perturbation theory. We verify that the leading non-planar correction to the anomalous dimension of the dual gauge theory operators is correctly recovered.Comment: 28 pages; v2: minor change

More comments on superstring interactions in the pp-wave background

We reconsider light-cone superstring field theory on the maximally supersymmetric pp-wave background. We find that the results for the fermionic Neumann matrices given so far in the literature are incomplete and verify our expressions by relating them to the bosonic Neumann matrices and proving several non-trivial consistency conditions among them, as for example the generalization of a flat space factorization theorem for the bosonic Neumann matrices. We also study the bosonic and fermionic constituents of the prefactor and point out a subtlety in the relation between continuum and oscillator basis expressions.Comment: v4: error in appendix C corrected, conclusions regarding alternative zero-mode vertex change

Localized closed string tachyon condensation

External Semina

Product footprint reporting for chemical companies

In the era of environmental sustainability, firms are put under pressure from the political and customers’ sides to act, particularly those in high feedstock and energy consuming sectors, like the chemical industry. A trend towards greener products is inevitably reaching intermediate sectors, so that sustainability reporting at product level arises as a necessity. Profound product footprint calculation lays the foundation for the definition of dedicated reduction targets and the development of climate-neutral products. In this article, we outline and compare two product footprint reporting frameworks: GHG Protocol’s Product Standard and the EU Commission’s Product Environmental Footprint, with the goal to provide firms in the chemical industry with guidance and insights on which aspects are more relevant and critical