Publications

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• Gravitational thermodynamics of causal diamonds in (A)dS

  Ted Jacobson, Manus R. Visser

  SciPost Phys. 7, 079 (2019) · published 10 December 2019 | Toggle abstract · pdf

  The static patch of de Sitter spacetime and the Rindler wedge of Minkowski spacetime are causal diamonds admitting a true Killing field, and they behave as thermodynamic equilibrium states under gravitational perturbations. We explore the extension of this gravitational thermodynamics to all causal diamonds in maximally symmetric spacetimes. Although such diamonds generally admit only a conformal Killing vector, that seems in all respects to be sufficient. We establish a Smarr formula for such diamonds and a ``first law" for variations to nearby solutions. The latter relates the variations of the bounding area, spatial volume of the maximal slice, cosmological constant, and matter Hamiltonian. The total Hamiltonian is the generator of evolution along the conformal Killing vector that preserves the diamond. To interpret the first law as a thermodynamic relation, it appears necessary to attribute a negative temperature to the diamond, as has been previously suggested for the special case of the static patch of de Sitter spacetime. With quantum corrections included, for small diamonds we recover the ``entanglement equilibrium'' result that the generalized entropy is stationary at the maximally symmetric vacuum at fixed volume, and we reformulate this as the stationarity of free conformal energy with the volume not fixed.

  74 citations

• EXCESS workshop: Descriptions of rising low-energy spectra

  P. Adari, A. Aguilar-Arevalo, D. Amidei, G. Angloher, E. Armengaud, C. Augier, L. Balogh, S. Banik, D. Baxter, C. Beaufort, G. Beaulieu, V. Belov, Y. Ben Gal, G. Benato, A. Benoît, A. Bento, L. Bergé, A. Bertolini, R. Bhattacharyya, J. Billard, I.M. Bloch, A. Botti, R. Breier, G. Bres, J-.L. Bret, A. Broniatowski, A. Brossard, C. Bucci, R. Bunker, M. Cababie, M. Calvo, P. Camus, G. Cancelo, L. Canonica, F. Cappella, L. Cardani, J.-F. Caron, N. Casali, G.del Castello, A. Cazes, R. Cerulli, B.A. Cervantes Vergara, D. Chaize, M. Chapellier, L. Chaplinsky, F. Charlieux, M. Chaudhuri, A.E. Chavarria, G. Chemin, R. Chen, H. Chen, F. Chierchie, I. Colantoni, J. Colas, J. Cooley, J.-M. Coquillat, E.C. Corcoran, S. Crawford, M. Crisler, A. Cruciani, P. Cushman, A. D'Addabbo, J.C. D'Olivo, A. Dastgheibi-Fard, M. De Jésus, Y. Deng, J.B. Dent, E.L. Depaoli, K. Dering, S. Dharani, S. Di Lorenzo, A. Drlica-Wagner, L. Dumoulin, D. Durnford, B. Dutta, L. Einfalt, A. Erb, A. Erhart, R. Essig, J. Estrada, E. Etzion, O. Exshaw, F. Favela-Perez, F. v. Feilitzsch, G. Fernandez Moroni, N. Ferreiro Iachellini, S. Ferriol, S. Fichtinger, E. Figueroa-Feliciano, J.-B. Filippini, D. Filosofov, J. A. Formaggio, M. Friedl, S. Fuard, D. Fuchs, A. Fuss, R. Gaïor, A. Garai, C. Garrah, J. Gascon , G. Gerbier, M. Ghaith, V.M. Ghete, D. Gift, I. Giomataris, G. Giroux, A. Giuliani, P. Gorel, P. Gorla, C. Goupy, J. Goupy, C. Goy, M. Gros, P. Gros, Y. Guardincerri, C. Guerin, V. Guidi, O. Guillaudin, S. Gupta, E. Guy, P. Harrington, D. Hauff, S. T. Heine, S. A. Hertel, S.E. Holland, Z. Hong, E.W. Hoppe, T.W. Hossbach, J.-C. Ianigro, V. Iyer, A. Jastram, M. Ješkovský, Y. Jin, J. Jochum, J. P. Johnston, A. Juillard, D. Karaivanov, V. Kashyap, I. Katsioulas, S. Kazarcev, M. Kaznacheeva, F. Kelly, B. Kilminster, A. Kinast, L. Klinkenberg, H. Kluck, P. Knights, Y. Korn, H. Kraus, B. von Krosigk, A. Kubik, N.A. Kurinsky, J. Lamblin, A. Langenkämper, S. Langrock, T. Lasserre, H. Lattaud, P. Lautridou, I. Lawson, S.J. Lee, M. Lee, A. Letessier-Selvon, D. Lhuillier, M. Li, Y.-T. Lin, A. Lubashevskiy, R. Mahapatra, S. Maludze, M. Mancuso, I. Manthos, L. Marini, S. Marnieros, R.D. Martin, A. Matalon, J. Matthews, B. Mauri, D. W. Mayer, A. Mazzolari, E. Mazzucato, H. Meyer zu Theenhausen, E. Michielin, J. Minet, N. Mirabolfathi, K. v. Mirbach, D. Misiak, P. Mitra, J-.L. Mocellin, B. Mohanty, V. Mokina, J.-P. Mols, A. Monfardini, F. Mounier, S. Munagavalasa, J.-F. Muraz, X.-F. Navick, T. Neep, H. Neog, H. Neyrial, K. Nikolopoulos, A. Nilima, C. Nones, V. Novati, P. O'Brien, L. Oberauer, E. Olivieri, M. Olmi, A. Onillon, C. Oriol, A. Orly, J.L. Orrell, T. Ortmann, C.T. Overman, C. Pagliarone, V. Palušová, P. Pari, P. K. Patel, L. Pattavina, F. Petricca, A. Piers, H. D. Pinckney, M.-C. Piro, M. Platt, D. Poda, D. Ponomarev, W. Potzel, P. Povinec, F. Pröbst, P. Privitera, F. Pucci, K. Ramanathan, J.-S. Real, T. Redon, F. Reindl, R. Ren, A. Robert, J.Da Rocha, D. Rodrigues, R. Rogly, J. Rothe, N. Rowe, S. Rozov, I. Rozova, T. Saab, N. Saffold, T. Salagnac, J. Sander, V. Sanglard, D. Santos, Y. Sarkis, V. Savu, G. Savvidis, I. Savvidis, S. Schönert, K. Schäffner, N. Schermer, J. Schieck, B. Schmidt, D. Schmiedmayer, C. Schwertner, L. Scola, M. Settimo, Ye. Shevchik, V. Sibille, I. Sidelnik, A. Singal, R. Smida, M. Sofo Haro, T. Soldner, J. Stachurska, M. Stahlberg, L. Stefanazzi, L. Stodolsky, C. Strandhagen, R. Strauss, A. Stutz, R. Thomas, A. Thompson, J. Tiffenberg, C. Tomei, M. Traina, S. Uemura, I. Usherov, L. Vagneron, W. Van De Pontseele, F.A. Vazquez de Sola Fernandez, M. Vidal, M. Vignati, A.L. Virto, M. Vivier, T. Volansky, V. Wagner, F. Wagner, J. Walker, R. Ward, S.L. Watkins, A. Wex, M. Willers, M.J. Wilson, L. Winslow, E. Yakushev, T.-T. Yu, M. Zampaolo, A. Zaytsev, V. Zema, D. Zinatulina, A. Zolotarova

  SciPost Phys. Proc. 9, 001 (2022) · published 9 August 2022 | Toggle abstract · pdf

  Many low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop’s data repository together with a plotting tool for visualization.

  62 citations

• Diving into a holographic superconductor

  Sean A. Hartnoll, Gary T. Horowitz, Jorrit Kruthoff, Jorge E. Santos

  SciPost Phys. 10, 009 (2021) · published 15 January 2021 | Toggle abstract · pdf

  Charged black holes in anti-de Sitter space become unstable to forming charged scalar hair at low temperatures $T < T_\text{c}$. This phenomenon is a holographic realization of superconductivity. We look inside the horizon of these holographic superconductors and find intricate dynamical behavior. The spacetime ends at a spacelike Kasner singularity, and there is no Cauchy horizon. Before reaching the singularity, there are several intermediate regimes which we study both analytically and numerically. These include strong Josephson oscillations in the condensate and possible 'Kasner inversions' in which after many e-folds of expansion, the Einstein-Rosen bridge contracts towards the singularity. Due to the Josephson oscillations, the number of Kasner inversions depends very sensitively on $T$, and diverges at a discrete set of temperatures $\{T_n\}$ that accumulate at $T_c$. Near these $T_n$, the final Kasner exponent exhibits fractal-like behavior.

  57 citations

• Search for scalar induced gravitational waves in the international pulsar timing array data release 2 and NANOgrav 12.5 years datasets

  Virgile Dandoy, Valerie Domcke, Fabrizio Rompineve

  SciPost Phys. Core 6, 060 (2023) · published 30 August 2023 | Toggle abstract · pdf

  We perform a Bayesian search in the latest Pulsar Timing Array (PTA) datasets for a stochastic gravitational wave (GW) background sourced by curvature perturbations at scales $10^5$ Mpc$^{-1}\lesssim$ k$\lesssim 10^8$ Mpc$^{-1}$. These re-enter the Hubble horizon at temperatures around and below the QCD crossover phase transition in the early Universe. We include a stochastic background of astrophysical origin in our search and properly account for constraints on the curvature power spectrum from the overproduction of primordial black holes (PBHs). We find that the International PTA Data Release 2 significantly favors the astrophysical model for its reported common-spectrum process, over the curvature-induced background. On the other hand, the two interpretations fit the NANOgrav 12.5 years dataset equally well. We then set new upper limits on the amplitude of the curvature power spectrum at small scales. These are independent from, and competitive with, indirect astrophysical bounds from the abundance of PBH dark matter. Upcoming PTA data releases will provide the strongest probe of the curvature power spectrum around the QCD epoch.

  55 citations

• The partial Bondi gauge: Further enlarging the asymptotic structure of gravity

  Marc Geiller, Céline Zwikel

  SciPost Phys. 13, 108 (2022) · published 15 November 2022 | Toggle abstract · pdf

  We present a detailed analysis of gravity in a partial Bondi gauge, where only the three conditions $g_{rr}=0=g_{rA}$ are fixed. We relax in particular the so-called determinant condition on the transverse metric, which is only assumed to admit a polyhomogeneous radial expansion. This is sufficient in order to build the solution space, which here includes a cosmological constant, time-dependent sources in the boundary metric, logarithmic branches, and an extra trace mode at subleading order in the transverse metric. The evolution equations are studied using the Newman--Penrose formalism in terms of covariant functionals identified from the Weyl scalars, and we build the explicit dictionary between this formalism and the tensorial Einstein equations. This provides in particular a new derivation of the (A)dS mass loss formula. We then study the holographic renormalisation of the symplectic potential, and the transformation laws under residual asymptotic symmetries. The advantage of the partial Bondi gauge is that it allows to contrast and treat in a unified manner the Bondi–Sachs and Newman--Unti gauges, which can each be reached upon imposing a further specific gauge condition. The differential determinant condition leads to the $\Lambda$-BMSW gauge, while a differential condition on $g_{ur}$ leads to a generalized Newman--Unti gauge. This latter gives access to a new asymptotic symmetry which acts on the asymptotic shear and further extends the $\Lambda$-BMSW group by an extra abelian radial translation. This generalizes results which we have recently obtained in three dimensions.

  49 citations

• Asymmetric dark matter: residual annihilations and self-interactions

  Iason Baldes, Marco Cirelli, Paolo Panci, Kalliopi Petraki, Filippo Sala, Marco Taoso

  SciPost Phys. 4, 041 (2018) · published 26 June 2018 | Toggle abstract · pdf

  Dark matter (DM) coupled to light mediators has been invoked to resolve the putative discrepancies between collisionless cold DM and galactic structure observations. However, $\gamma$-ray searches and the CMB strongly constrain such scenarios. To ease the tension, we consider asymmetric DM. We show that, contrary to the common lore, detectable annihilations occur even for large asymmetries, and derive bounds from the CMB, $\gamma$-ray, neutrino and antiproton searches. We then identify the viable space for self-interacting DM. Direct detection does not exclude this scenario, but provides a way to test it.

  49 citations

• AMS-02 antiprotons and dark matter: Trimmed hints and robust bounds

  Francesca Calore, Marco Cirelli, Laurent Derome, Yoann Genolini, David Maurin, Pierre Salati, Pasquale D. Serpico

  SciPost Phys. 12, 163 (2022) · published 18 May 2022 | Toggle abstract · pdf

  Based on 4 yr AMS-02 antiproton data, we present bounds on the dark matter (DM) annihilation cross section vs. mass for some representative final state channels. We use recent cosmic-ray propagation models, a realistic treatment of experimental and theoretical errors, and an updated calculation of input antiproton spectra based on a recent release of the PYTHIA code. We find that reported hints of a DM signal are statistically insignificant; an adequate treatment of errors is crucial for credible conclusions. Antiproton bounds on DM annihilation are among the most stringent ones, probing thermal DM up to the TeV scale. The dependence of the bounds upon propagation models and the DM halo profile is also quantified. A preliminary estimate reaches similar conclusions when applied to the 7 years AMS-02 dataset, but also suggests extra caution as for possible future claims of DM excesses.

  46 citations

• Holographic thermal correlators from supersymmetric instantons

  Matthew Dodelson, Alba Grassi, Cristoforo Iossa, Daniel Panea Lichtig, Alexander Zhiboedov

  SciPost Phys. 14, 116 (2023) · published 16 May 2023 | Toggle abstract · pdf

  We present an exact formula for the thermal scalar two-point function in four-dimensional holographic conformal field theories. The problem of finding it reduces to the analysis of the wave equation on the AdS-Schwarzschild background. The two-point function is computed from the connection coefficients of the Heun equation, which can be expressed in terms of the Nekrasov-Shatashvili partition function of an $SU(2)$ supersymmetric gauge theory with four fundamental hypermultiplets. The result is amenable to numerical evaluation upon truncating the number of instantons in the convergent expansion of the partition function. We also examine it analytically in various limits. At large spin the instanton expansion of the thermal two-point function directly maps to the light-cone bootstrap analysis of the heavy-light four-point function. Using this connection, we compute the OPE data of heavy-light double-twist operators. We compare our prediction to the perturbative results available in the literature and find perfect agreement.

  43 citations

• The derivative expansion in asymptotically safe quantum gravity: general setup and quartic order

  Benjamin Knorr

  SciPost Phys. Core 4, 020 (2021) · published 9 September 2021 | Toggle abstract · pdf

  We present a general framework to systematically study the derivative expansion of asymptotically safe quantum gravity. It is based on an exact decoupling and cancellation of different modes in the Landau limit, and implements a correct mode count as well as a regularisation based on geometrical considerations. It is applicable independent of the truncation order. To illustrate the power of the framework, we discuss the quartic order of the derivative expansion and its fixed point structure as well as physical implications.

  39 citations

• Quark formation and phenomenology in binary neutron-star mergers using V-QCD

  Samuel Tootle, Christian Ecker, Konrad Topolski, Tuna Demircik, Matti Järvinen, Luciano Rezzolla

  SciPost Phys. 13, 109 (2022) · published 16 November 2022 | Toggle abstract · pdf

  Using full 3+1 dimensional general-relativistic hydrodynamic simulations of equal- and unequal-mass neutron-star binaries with properties that are consistent with those inferred from the inspiral of GW170817, we perform a detailed study of the quark-formation processes that could take place after merger. We use three equations of state consistent with current pulsar observations derived from a novel finite-temperature framework based on V-QCD, a non-perturbative gauge/gravity model for Quantum Chromodynamics. In this way, we identify three different post-merger stages at which mixed baryonic and quark matter, as well as pure quark matter, are generated. A phase transition triggered collapse already $\lesssim 10\,\rm{ms}$ after the merger reveals that the softest version of our equations of state is actually inconsistent with the expected second-long post-merger lifetime of GW170817. Our results underline the impact that gravitational wave observations of binary neutron-star mergers can have in constraining the equation of state of nuclear matter, especially in its most extreme regimes.

  35 citations