activity
20202026
most citedThe monopole problem in holographic cosmology

1 citations · 1 across the 5 of their papers we have counts for

collaborators

6 papers

hep-th2026

Boundary observables in string field theory

Klaus Kaja, Carlo Maccaferri, Ulisses Portugal +1

Starting from the gauge invariant action for free string field theory with boundary recently constructed in 2506.05969, we define new gauge invariant observables which are analogou…

hep-th2024

Heterotic String Field Theory with Manifest Spacetime Supersymmetry

Nathan Berkovits, Ulisses M. Portugal

Using the hybrid formalism with manifest spacetime supersymmetry, we construct the quadratic term in the heterotic superstring field theory action. As in open superstri…

hep-th2024

Super Yang-Mills Action from Hybrid Superstring Field Theory

Ulisses M Portugal

We explicitly compute the effective action from Open Superstring Field Theory in the hybrid formalism to quartic order in the limit, and show that it reproduces t…

hep-th2024

A two parameter family of lightcone-like hyperbolic string vertices

Vinicius Bernardes, Ulisses Portugal

We introduce a two parameter family of string field theory vertices, which we refer to as hyperbolic Kaku vertices. It is defined in terms of hyperbolic metrics on the Riemann surf…

hep-th2021

Instanton Solutions in Open Superstring Field Theory

Nathan Berkovits, Vilson Fabricio Juliatto, Ulisses M. Portugal

Open superstring field theory admits a "hybrid" formulation where N = 1 D = 4 supersymmetry is manifest for Calabi-Yau compactifications to four dimensions. Using this formulation,…

hep-th2020★ 1 cited

The monopole problem in holographic cosmology

Horatiu Nastase, Ulisses M. Portugal

In this letter we clarify that the monopole problem can always be solved in bosonic holographic cosmology, by the analogue of "dilution" in inflation, which is the fact that the {\…