Tata Institute of Fundamental Research

About: Tata Institute of Fundamental Research is a education organization based out in Mumbai, Maharashtra, India. It is known for research contribution in the topics: Magnetization & Large Hadron Collider. The organization has 7786 authors who have published 21742 publications receiving 622368 citations. The organization is also known as: TIFR.

Meson masses in electromagnetic fields with Wilson fermions

Abstract: We determine the light meson spectrum in QCD in the presence of background magnetic fields using quenched Wilson fermions. Our continuum extrapolated results indicate a monotonous reduction of the connected neutral pion mass as the magnetic field grows. The vector meson mass is found to remain nonzero, a finding relevant for the conjectured $\ensuremath{\rho}$-meson condensation at strong magnetic fields. The continuum extrapolation was facilitated by adding a novel magnetic field--dependent improvement term to the additive quark mass renormalization. Without this term, sizable lattice artifacts that would deceptively indicate an unphysical rise of the connected neutral pion mass for strong magnetic fields are present. We also investigate the impact of these lattice artifacts on further observables like magnetic polarizabilities and discuss the magnetic field--induced mixing between $\ensuremath{\rho}$-mesons and pions. We also derive Ward-Takashi identities for $\mathrm{QCD}+\mathrm{QED}$ both in the continuum formulation and for (order $a$--improved) Wilson fermions.

String Theory as a Higher Spin Theory

Abstract: The symmetries of string theory on $$ {\mathrm{AdS}}_3\times {\mathrm{S}}^3\times {\mathbb{T}}^4 $$ at the dual of the symmetric product orbifold point are described by a so-called Higher Spin Square (HSS). We show that the massive string spectrum in this background organises itself in terms of representations of this HSS, just as the matter in a conventional higher spin theory does so in terms of representations of the higher spin algebra. In particular, the entire untwisted sector of the orbifold can be viewed as the Fock space built out of the multiparticle states of a single representation of the HSS, the so-called ‘minimal’ representation. The states in the twisted sector can be described in terms of tensor products of a novel family of representations that are somewhat larger than the minimal one.

Self-Assembly of Template-Directed J-Aggregates of Porphyrin

Abstract: This communication describes the first observation of J-aggregate formation of a porphyrin by a polymer template. The chirality of the polymer is superimposed on the J-aggregate. Regular micrometer...