Second Holography and Dense Matter Workshop (featuring Meeting of Compact Objects working group of the GW GdR)

Session

Holography & Dense Matter

17 sept. 2025, 15:50

APC Laboratory (Paris)

19. Neutron Star Mergers: Multimessenger Probes of Extreme Matter

Pablo Bosch

17/09/2025 15:50

Binary neutron star mergers are critical for understanding the dynamics of dense matter, the origin of gravitational waves, and the formation channels of the heaviest elements through the r-process. I will review how long-lived remnants can act as central engines for multimessenger observations. I will then discuss how we can identify phase transitions within neutron stars or their remnants...

17. QCD in the cores of neutron stars

Aleksi Kurkela

18/09/2025 09:00

Neutron stars are the densest astrophysical objects in our universe, reaching densities as high as those realized in ultrarelativistic heavy-ion collisions at the LHC. In these collisions ordinary nuclear matter melts into a new phase of elementary particle matter, quark matter. This naturally raises the question: does quark matter also exist inside neutron stars? The rapid advancement in...

18. A new perturbative approach to dense matter: thermal Loop Tree Duality

Aleksi Vuorinen

18/09/2025 10:30

It is well established that the high-density constraint from perturbative QCD, though directly applicable only at densities exceeding those inside neutron stars, plays a central role in the model-independent inference of the neutron-star equation of state (EoS). The completion of the next-to-next-to-next-to-leading order (N3LO) pressure of dense quark matter is expected to significantly...

27. Microscopic description of critical bubbles

Javier Subils

18/09/2025 11:30

First-order phase transitions in the early Universe and inside neutron stars could leave observable imprints, including a stochastic gravitational wave background or characteristic waveforms in specific frequency ranges. Predicting these signals requires precise understanding of critical bubbles, often addressed using effective field theory or perturbation theory. In this talk, I will present...

20. Forming and Evaporating Black Holes from Strongly Coupled Matter

David Mateos

18/09/2025 14:30

Holography has provided valuable insights into the time evolution of strongly coupled gauge theories in a fixed spacetime. However, this framework is insufficient if this spacetime is dynamical. We present a scheme to evolve a four-dimensional, strongly interacting gauge theory coupled to four-dimensional dynamical gravity in the semiclassical regime. We apply this framework to the description...

21. From Ringdowns to Critical Points: Constraining Dense Matter with Neutron Stars

Christian Ecker

18/09/2025 15:30

Astrophysical measurements, especially gravitational waves (GW) from binary neutron star (BNS) mergers, are promising tools to infer the largely unknown properties of dense QCD matter at densities that are presently inaccessible to first-principles theory and laboratory experiments.
In the first part of my talk, I will show how the correlation between the ratio of energy and angular-momentum...

22. On effective action from holography

Niko Jokela

19/09/2025 09:00

First-order phase transitions in strongly coupled systems are of central interest, both for fundamental physics and for their potential cosmological signatures such as gravitational waves. In this talk, I will explain how holography provides a framework to study critical bubble nucleation. I will describe two complementary approaches: constructing a two-derivative effective action and solving...

23. Phases of dense QCD and neutron stars from holography

Andreas Schmitt

19/09/2025 10:30

I will review recent progress in the Witten-Sakai-Sugimoto model to understand strongly coupled phases of matter and their application to neutron stars. I will start from pion condensation at finite isospin chemical potential, where lattice QCD results are available to test the holographic results. Baryonic matter can be added to predict the phase structure at finite baryon and isospin...

24. Towards an improved holographic equation of state for hot and dense QCD

Matti Järvinen

19/09/2025 11:30

I discuss recent studies which aim at improving the description of the equation of state and the phase diagram of QCD by using the holographic V-QCD framework. Such improvements include turning on a finite strange quark mass, comparison to lattice QCD data at finite mass, developing a simple model for a color superconducting phase, and analyzing isospin asymmetry in holographic nuclear matter.

25. Hall droplet baryons in holographic QCD

Francesco Bigazzi

19/09/2025 14:30

I will present a first-principle construction of baryons as quantum Hall droplets in single-flavor holographic QCD, focusing on the top-down Witten-Sakai-Sugimoto model. The baryons are described as charged D6-branes with a circular boundary on a flavor D8-brane in the Type IIA background sourced by N D4-branes wrapped on a circle. The holographic description allows to calculate their...

26. From top-down to bottom-up: a new construction for holographic color-superconductivity

Edwan Préau

19/09/2025 16:00

Taking inspiration from top-down constructions, I revisit the problem of constructing a color superconducting phase in bottom-up holography. The model introduced describes the five-dimensional dynamics of a scalar field dual to a chiral symmetry breaking condensate, which is coupled to the RR 4-form. The coupling is given by a topological WZ term, which is elegantly responsible both for scalar...