Breakdown of the Equal Area Law for Holographic Entanglement Entropy

We investigate a holographic version of Maxwell's equal area law analogous to that for the phase transition in the black hole temperature/black hole entropy plane of a charged AdS black hole. We consider proposed area laws for both the black hole temperature/holographic entanglement entropy plane and the black hole temperature/2-point correlation function plane. Despite recent claims to the contrary, we demonstrate numerically that neither proposal is valid. We argue that there is no physical reason to expect such a construction in these planes.Comment: 17 pages, 8 figures. v2: Added appendix and discussio

02. Lessons from a Snowflake

https://crossworks.holycross.edu/poetry2023/1002/thumbnail.jp

20. Bareness

https://crossworks.holycross.edu/poetry2023/1020/thumbnail.jp

Museum, Field, Colony: collecting, displaying and governing people and things

The papers selected for this special issue of Museum and Society have their beginnings in the workshop, ‘Colonial Governmentalities’, held in late October 2012 and hosted by the Institute of Culture and Society, University of Western Sydney, followed by the seminar ‘Reassembling the material,’ hosted by the Museum and Heritage Studies programmes at Victoria University of Wellington in early November. The stimulus for these events was the international research collaboration, ‘Museum, Field, Metropolis, Colony: Practices of Social Governance funded by the Australian Research Council’

Converting dark matter to dark radiation does not solve cosmological tensions

Tensions between cosmological parameters (in particular the local expansion rate $H_0$ and the amplitude of matter clustering $S_8$) inferred from low-redshift data and data from the cosmic microwave background (CMB) and large-scale structure (LSS) experiments have inspired many extensions to the standard cosmological model, $\Lambda$CDM. Models which simultaneously lessen both tensions are of particular interest. We consider one scenario with the potential for such a resolution, in which some fraction of the dark matter has converted into dark radiation since the release of the CMB. Such a scenario encompasses and generalizes the more standard "decaying dark matter" model, allowing additional flexibility in the rate and time at which the dark matter converts into dark radiation. In this paper, we constrain this scenario with a focus on exploring whether it can solve (or reduce) these tensions. We find that such a model is effectively ruled out by low-$\ell$ CMB data, in particular by the reduced peak-smearing due to CMB lensing and the excess Integrated Sachs--Wolfe (ISW) signal caused by the additional dark energy density required to preserve flatness after dark matter conversion into dark radiation. Thus, such a model does not have the power to reduce these tensions without further modifications. This conclusion extends and generalizes related conclusions derived for the standard decaying dark matter model.Comment: 19 pages, 8 figures. Our modified Boltzmann code is available at https://github.com/fmccarthy/class_DMDR Re-uploaded with some more details on the failure of the DMDR model (v2); Reuploaded with the version published by PRD (v3

Component-separated, CIB-cleaned thermal Sunyaev--Zel'dovich maps from Planck\textit{Planck} PR4 data with a flexible public needlet ILC pipeline

We use the full-mission $\textit{Planck}$ PR4 data to construct maps of the thermal Sunyaev$--$Zel'dovich effect (Compton-$y$ parameter) in our Universe. To do so, we implement a custom needlet internal linear combination (NILC) pipeline in a Python package, $\texttt{pyilc}$, which we make publicly available. We publicly release our Compton-$y$ maps, which we construct using various constrained ILC ("deprojection") options in order to minimize contamination from the cosmic infrared background (CIB) in the reconstructed signal. In particular, we use a moment-based deprojection which minimizes sensitivity to the assumed frequency dependence of the CIB. Our code $\texttt{pyilc}$ performs needlet or harmonic ILC on mm-wave sky maps in a flexible manner, with options to deproject various components on all or some scales. We validate our maps and compare them to the official $\textit{Planck}$ 2015 $y$-map, finding that we obtain consistent results on large scales and 10-20$\%$ lower noise on small scales. We expect that these maps will be useful for many auto- and cross-correlation analyses; in a companion paper, we use them to measure the tSZ -- CMB lensing cross-correlation. We anticipate that $\texttt{pyilc}$ will be useful both for data analysis and for pipeline validation on simulations to understand the propagation of foreground components through a full NILC pipeline.Comment: 28 pages, 15 figures. Public maps and other data products are available at https://users.flatironinstitute.org/~fmccarthy/ymaps_PR4_McCH23/ ; public code is available at https://github.com/jcolinhill/pyilc . V2: some additional notes about the effective CIB SED parameters and the halo model, also removed discussion about apodization of our maps and Planck map

Late-universe signals in the microwave sky: extragalactic dust, electrons, and other baryonic effects

This thesis collects much of the work I have done over the last four years as a PhD student. It has two focuses. Part 1 discusses gravitational radiation emitted from two maximally charged black holes in Einstein--Maxwell--dilaton theory, while Part 2 focuses on cosmological probes of late-universe physics. Black holes are some of the most interesting solutions to Einstein's equations, the equations that govern the curvature of the spacetime we inhabit. The gravitational field around them is stronger than around any other astrophysical object, and the interaction of two black holes can cause strong disturbances in the spacetime, leading to the radiation of gravitational waves. Gravitational radiation is usually a complex problem that must be studied numerically, and analytic solutions are rare. However, in Einstein--Maxwell (EM) theory, where the Einstein equations are supplemented with the Maxwell equations governing the behaviour of electromagnetic fields, there exists a configuration of black holes which have electric charge which causes a repulsive force that counteracts their gravitational attraction. These black holes can be evolved quasi-statically leading to gravitational radiation that can be analytically approximated. In Chapter 3 of this thesis we analytically approximate the radiation when the EM equations are further supplemented with a dilaton (scalar) field. The second part of this thesis relates to work I have done in relation to late-universe probes and secondary cosmic microwave background (CMB) effects, in particular motivated by the upcoming Simons Observatory and CMB-S4 CMB surveys. The CMB has been detected and mapped with exquisite detail by the Planck satellite on arcminute scales, and these experiments will extend to even smaller angular scales. In this regime ``secondary'' effects sourced in the late universe will dominate, in particular CMB lensing due to large masses and the interaction of the CMB with electrons (the Sunyaev--Zel'dovich effect). We also get closer to the regime in which the cosmic infrared background (CIB), sourced by thermal radiation from dust in star-forming galaxies, starts to dominate over the CMB. Robust and consistent modelling is required to understand how the different signals relate to and correlate with each other. In this thesis we consider how various combinations of these phenomena correlate in different ways. Chapter 7 discusses how the correlation between CMB lensing and the CIB can be used to improve models of the latter. Chapter 8 discusses how CIB maps can be combined with Sunyaev--Zel'dovich probes to reconstruct the velocity field of the universe on the largest scales. In Chapters 9 and 10 we discuss how complex late-universe interactions can bias the inference of fundamental physics from the CMB lensing and lensed CMB maps, and develop several mitigation methods to ensure unbiased inference