Book Section records
https://feeds.library.caltech.edu/people/Carroll-S-M/book_section.rss
A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 13:26:12 +0000Dark matter and dark radiation
https://resolver.caltech.edu/CaltechAUTHORS:20100715-111557235
Authors: {'items': [{'id': 'Ackerman-L', 'name': {'family': 'Ackerman', 'given': 'Lotty'}}, {'id': 'Buckley-M-R', 'name': {'family': 'Buckley', 'given': 'Matthew R.'}}, {'id': 'Carroll-S-M', 'name': {'family': 'Carroll', 'given': 'Sean M.'}, 'orcid': '0000-0002-4226-5758'}, {'id': 'Kamionkowski-M', 'name': {'family': 'Kamionkowski', 'given': 'Marc'}, 'orcid': '0000-0001-7018-2055'}]}
Year: 2010
We explore the feasibility and astrophysical consequences of a new long-range U(1) gauge field ("dark electromagnetism") that couples only to dark matter, not to the Standard Model. The dark matter consists of an equal number of positive and negative charges under the new force, but annihilations are suppressed if the dark matter mass is sufficiently high and the dark fine-structure constant α is sufficiently small. The correct relic abundance can be obtained if the dark matter also couples to the conventional weak interactions, and we verify that this is consistent with particle-physics constraints. The primary limit on a comes from the demand that the dark matter be effectively collisionless in galactic dynamics, which implies α ≾ 10^(-3) for TeV-scale dark matter. These values are easily compatible with constraints from structure formation and primordial nucleosynthesis. We raise the prospect of interesting new plasma effects in dark matter dynamics, which remain to be explored. This proceedings is based on the work presented originally in.(1)https://authors.library.caltech.edu/records/qvvh9-2y366The origin of the universe and the arrow of time
https://resolver.caltech.edu/CaltechAUTHORS:20170316-132438668
Authors: {'items': [{'id': 'Carroll-S-M', 'name': {'family': 'Carroll', 'given': 'Sean M.'}, 'orcid': '0000-0002-4226-5758'}]}
Year: 2010
DOI: 10.1109/AERO.2010.5447043
One of the most obvious facts about the universe is that the past is different from the future. The world around us is full of irreversible processes: we can turn an egg into an omelet, but can't turn an omelet into an egg. Physicists have codified this difference into the Second Law of Thermodynamics: the entropy of a closed system always increases with time. But why? The ultimate explanation is to be found in cosmology: special conditions in the early universe are responsible for the arrow of time. I will talk about the nature of time, the origin of entropy, and how what happened before the Big Bang may be responsible for the arrow of time we observe today.https://authors.library.caltech.edu/records/9zzjd-rmx46Many Worlds, the Born Rule, and Self-Locating Uncertainty
https://resolver.caltech.edu/CaltechAUTHORS:20141216-203110170
Authors: {'items': [{'id': 'Carroll-S-M', 'name': {'family': 'Carroll', 'given': 'Sean M.'}, 'orcid': '0000-0002-4226-5758'}, {'id': 'Sebens-C-T', 'name': {'family': 'Sebens', 'given': 'Charles T.'}}]}
Year: 2014
DOI: 10.1007/978-88-470-5217-8_10
We provide a derivation of the Born Rule in the context of the Everett (Many-Worlds) approach to quantum mechanics. Our argument is based on the idea of self-locating uncertainty: in the period between the wave function branching via decoherence and an observer registering the outcome of the measurement, that observer can know the state of the universe precisely without knowing which branch they are on. We show that there is a uniquely rational way to apportion credence in such cases, which leads directly to the Born Rule. [Editors note: for a video of the talk given by Prof. Carroll at the Aharonov-80 conference in 2012 at Chapman University, see quantum.chapman.edu/talk-14.]https://authors.library.caltech.edu/records/9cdj7-axw89Mad-Dog Everettianism: Quantum Mechanics at Its Most Minimal
https://resolver.caltech.edu/CaltechAUTHORS:20180228-094539014
Authors: {'items': [{'id': 'Carroll-S-M', 'name': {'family': 'Carroll', 'given': 'Sean M.'}, 'orcid': '0000-0002-4226-5758'}, {'id': 'Singh-Ashmeet', 'name': {'family': 'Singh', 'given': 'Ashmeet'}, 'orcid': '0000-0002-4404-1416'}]}
Year: 2019
DOI: 10.1007/978-3-030-11301-8_10
To the best of our current understanding, quantum mechanics is part of the most fundamental picture of the universe. It is natural to ask how pure and minimal this fundamental quantum description can be. The simplest quantum ontology is that of the Everett or Many-Worlds interpretation, based on a vector in Hilbert space and a Hamiltonian. Typically one also relies on some classical structure, such as space and local configuration variables within it, which then gets promoted to an algebra of preferred observables. We argue that even such an algebra is unnecessary, and the most basic description of the world is given by the spectrum of the Hamiltonian (a list of energy eigenvalues) and the components of some particular vector in Hilbert space. Everything else—including space and fields propagating on it—is emergent from these minimal elements.https://authors.library.caltech.edu/records/5f5w2-x7g75Mysteries of Modern Physics
https://resolver.caltech.edu/CaltechAUTHORS:20230420-574389200.2
Authors: {'items': [{'id': 'Carroll-S-M', 'name': {'family': 'Carroll', 'given': 'Sean M.'}, 'orcid': '0000-0002-4226-5758'}]}
Year: 2022
DOI: 10.1017/9781009232517.003
This chapter guides the reader through three related enigmas of modern physics. The first is a mystery of quantum mechanics. Important aspects of quantum mechanics are still not truly understood, although competing theories have been proposed, including the Many-Worlds approach. The second enigma is the emergence of spacetime, and especially the way it interacts with gravity. Rather than following the traditional methodology of 'quantising' classical theories, the author proposes an alternative approach and instead seeks gravity within quantum mechanics. The chapter concludes with a discussion of the mystery of the arrow of time: what distinguishes the past from the future. Together, these three mysteries of modern physics serve as an important reminder of the endurance of enigmas in the very foundations of scholarly fields. Re-examining founding principles can provide a constructive alternative means of investigating mysteries, not only in modern science but also across other disciplines.https://authors.library.caltech.edu/records/p863p-e9c71