arXiv subjects

Girish S Vishwa

Publications and source records attributed to Girish S Vishwa.

3 recordsLinked to original sources

arXiv2026

On the boundary Carrollian conformal algebra

We initiate the mathematical study of the boundary Carrollian conformal algebra (BCCA), an infinite-dimensional Lie algebra recently discovered in the context of Carrollian physics. The BCCA is an intriguing object from both physical and mathematical perspectives, since it is a filtered but not graded Lie algebra. In this paper, we first construct some modules for the BCCA and one of its subalgebras, which we call $\mathcal{O}$, by restriction of well-known modules of the BMS$_3$ and Witt algebras respectively. Along the way, we prove the irreducibility criteria for the so-called ``induced modules'' of the BMS$_3$ algebra (which we prefer to call massive modules to avoid ambiguity) and show that this is the same criteria for the irreducibility of the Verma modules of the BMS$_3$ algebra. Interestingly, the modules generated by the action of the BCCA on the generating vector of the massive modules are also irreducible under the same criteria. When this criteria holds, every massive module decomposes into a direct sum of two BCCA-submodules, each of which we conjecture to be indecomposable. Meanwhile, restricting Verma modules to the BCCA and $\mathcal{O}$ leads to free or ``almost free'' modules, which are not particularly interesting from a representation-theoretic viewpoint. This motivates the construction of BCCA modules intrinsically. To do this, we go through some structure theory on the BCCA to define a new basis and a decreasing filtration on the algebra, using which we construct Whittaker modules over the BCCA and the subalgebra $\mathcal{O}$ and prove criteria for their irreducibility.

math.RT↗

arXiv2025

Non-relativistic quantum strings from gauged WZW models

We construct non-relativistic quantum strings from gauged Wess--Zumino--Witten (WZW) models. We depart from the fact that Lie groups with a bi-invariant galilean structure can be seen as the quotient by a null central subgroup of a generalised Nappi--Witten group. We implement the quotient by a chiral null gauging. We use a particular free field realisation of the Nappi--Witten current algebra to compute the Virasoro BRST cohomology of the gauged WZW model, resulting in a closed string theory reminiscent of the bosonic Gomis--Ooguri string, but whose spectrum differs slightly between the holomorphic and antiholomorphic sectors.

hep-th↗

arXiv2025

The BRST quantisation of chiral BMS-like field theories

The BMS$_3$ Lie algebra belongs to a one-parameter family of Lie algebras obtained by centrally extending abelian extensions of the Witt algebra by a tensor density representation. In this paper we call such Lie algebras $\hat{\mathfrak{g}}_λ$, with BMS$_3$ corresponding to the universal central extension of $λ= -1$. We construct the BRST complex for $\hat{\mathfrak{g}}_λ$ in two different ways: one in the language of semi-infinite cohomology and the other using the formalism of vertex operator algebras. We pay particular attention to the case of BMS$_3$ and discuss some natural field-theoretical realisations. We prove two theorems about the BRST cohomology of $\hat{\mathfrak{g}}_λ$. The first is the construction of a quasi-isomorphic embedding of the chiral sector of any Virasoro string as a $\hat{\mathfrak{g}}_λ$ string. The second is the isomorphism (as Batalin-Vilkovisky algebras) of any $\hat{\mathfrak{g}}_λ$ BRST cohomology and the chiral ring of a topologically twisted $N{=}2$ superconformal field theory.

hep-th↗