102 citations · 447 across the 25 of their papers we have counts for
25 papers
Quantum nucleation of black hole mimickers via chaos dominated tunneling
Ulf Danielsson, Suvendu Giri, Vyshnav Mohan +1
Black hole mimickers, ultracompact horizonless objects, have been proposed as alternatives to black holes in a variety of settings, including extensions of general relativity and s…
Dark bubbles, dark dimensions and fat gravitons
Ulf Danielsson, Suvendu Giri
The dark bubble model explains the existence of a positive cosmological constant by making explicit use of the instabilities underlying the de Sitter swampland conjectures to make…
Weak gravity at micron scales from dark bubble cosmology and its cosmological consequences
Ulf Danielsson, Suvendu Giri
The dark bubble model makes a positive cosmological constant natural in string theory, and predicts several new physical phenomena within reach in the near future. In this paper we…
Black hole mimickers: from theory to observation
Cosimo Bambi, Ramy Brustein, Vitor Cardoso +16
The black hole paradigm, while remarkably successful, raises fundamental questions-both classical and quantum-about the nature of spacetime, horizons, and singularities. Black hole…
Exploring Black Hole Mimickers: Electromagnetic and Gravitational Signatures of AdS Black Shells
Suvendu Giri, Ulf Danielsson, Luis Lehner +1
We study electromagnetic and gravitational properties of AdS black shells (also referred to as AdS black bubbles) -- a class of quantum gravity motivated black hole mimickers, that…
Proving the 6d a-theorem with the double affine Grassmannian
Marco Fazzi, Suvendu Giri, Paul Levy
This paper contains two results of independent interest, the first being more mathematical in nature whereas the second more physical. We first show that the hierarchy of Higgs bra…
Shedding light on dark bubble cosmology
Ivano Basile, Ulf Danielsson, Suvendu Giri +1
Dark bubble cosmology is an alternative paradigm to compactification, which can circumvent issues of moduli stabilization and scale separation. In this paper we investigate how ele…
Horizonless black hole mimickers with spin
Ulf Danielsson, Suvendu Giri
In this paper, we study rotating horizon less black shells as an alternative to Kerr black holes. We make use of Ernst's potential to solve the Einstein equations perturbatively in…
The Higgs branch of Heterotic ALE instantons
Michele Del Zotto, Marco Fazzi, Suvendu Giri
We begin a study of the Higgs branch of six-dimensional little string theories governing the worldvolumes of heterotic ALE instantons. We give a description of this space b…
A new vista on the Heterotic Moduli Space from Six and Three Dimensions
Michele Del Zotto, Marco Fazzi, Suvendu Giri
We settle a long-standing question about the hypermultiplet moduli spaces of the heterotic strings on ALE singularities. These heterotic backgrounds are specified by the singularit…
Hierarchies of RG flows in 6d massive E-strings
Marco Fazzi, Simone Giacomelli, Suvendu Giri
We extend the analysis of arXiv:2208.11703 to the 6d SCFTs known as massive E-string theories, which can be engineered in massive Type IIA with D8-branes close to…
Features of a dark energy model in string theory
Souvik Banerjee, Ulf Danielsson, Suvendu Giri
In this paper we clear up misconceptions concerning the dark bubble model as a realization of dark energy in string theory. In particular we point out important differences with Ra…
Hierarchy of RG flows in 6d orbi-instantons
Marco Fazzi, Suvendu Giri
M5-branes probing the intersection between the orbifold and an wall give rise to 6d SCFTs known as ADE-type orbi-instantons. At fixed…
On the Stability of String Theory Vacua
Suvendu Giri, Luca Martucci, Alessandro Tomasiello
Vacuum compactifications may suffer from instabilities under small perturbations or tunnel effects; both are difficult to analyze. In this paper we consider the issue from a higher…
Black holes with spindles at the horizon
Suvendu Giri
We construct and solutions in F(4) gauged supergravity in six dimensions, where is a two dimensional manifold of non-constant curvat…
Re-examining the stability of rotating horizonless black shells mimicking Kerr black holes
Ulf Danielsson, Suvendu Giri
In arXiv:1705.10172 a string theory inspired alternative to gravitational collapse was proposed, consisting of a bubble of AdS space made up of ingredients from string theory. Thes…
Curing with hemlock: escaping the swampland using instabilities from string theory
Souvik Banerjee, Ulf Danielsson, Suvendu Giri
In this essay we will take a wonderful ride on a dark bubble with strings attached, which carries our universe out of the swampland and makes it realizable in the landscape of stri…
Dark bubbles and black holes
Souvik Banerjee, Ulf Danielsson, Suvendu Giri
In this paper we study shells of matter and black holes on the expanding bubbles realizing de Sitter space, that were proposed in arXiv:1807.01570. We construct explicit solutions…
Bubble needs strings
Souvik Banerjee, Ulf Danielsson, Suvendu Giri
In this paper, we want to emphasize the pivotal role played by strings in the model realizing de Sitter using an expanding bubble, proposed and subsequently developed in arXiv:1807…
Dark bubbles: decorating the wall
Souvik Banerjee, Ulf Danielsson, Suvendu Giri
Motivated by the difficulty of constructing de Sitter vacua in string theory, a new approach was proposed in arXiv:1807.01570 and arXiv:1907.04268, where four dimensional de Sitter…
de Sitter Cosmology on an expanding bubble
Souvik Banerjee, Ulf Danielsson, Giuseppe Dibitetto +2
Constructing an explicit compactification yielding a metastable de Sitter (dS) vacuum in a UV consistent string theory is an incredibly difficult open problem. Motivated by this is…
Constructing stable de Sitter in M-theory from higher curvature corrections
Johan Blåbäck, Ulf Danielsson, Giuseppe Dibitetto +1
We consider dimensional reductions of M-theory on with the inclusion of arbitrary metric flux and spacetime filling KK monopoles. With these ing…
Emergent de Sitter Cosmology from Decaying AdS
Souvik Banerjee, Ulf Danielsson, Giuseppe Dibitetto +2
Recent developments in string compactifications demonstrate obstructions to the simplest constructions of low energy cosmologies with positive vacuum energy. The existence of obsta…
Observational signatures from horizonless black shells imitating rotating black holes
Ulf Danielsson, Suvendu Giri
In arXiv:1705.10172 it was proposed that string theory replaces Schwarzschild black holes with horizonless thin shells with an AdS interior. In this paper we extend the analysis to…