國立虎尾科技大學 |

Axions in a Dark Universe : = Dark Matter Behavior and Novel Dynamics Inform Cosmological Observations.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Axions in a Dark Universe :/
Reminder of title:	Dark Matter Behavior and Novel Dynamics Inform Cosmological Observations.
Author:	Allali, Itamar J.
Description:	1 online resource (269 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 84-11, Section: B.
Contained By:	Dissertations Abstracts International84-11B.
Subject:	Theoretical physics. -
Online resource:	click for full text (PQDT)
ISBN:	9798379562823

Axions in a Dark Universe : = Dark Matter Behavior and Novel Dynamics Inform Cosmological Observations.
Allali, Itamar J.

Axions in a Dark Universe :Dark Matter Behavior and Novel Dynamics Inform Cosmological Observations. - 1 online resource (269 pages)

Source: Dissertations Abstracts International, Volume: 84-11, Section: B.

Thesis (Ph.D.)--Tufts University, 2023.

Includes bibliographical references

Despite its crucial role in cosmology, little is known about the precise nature of dark matter. This work investigates the nature of dark matter, primarily the QCD axion and other axion-like particles, which are motivated from particle physics. First, I explore the possibility of long-lived quantum superpositions of macroscopic dark matter states in the galaxy. Schrodinger cat states, which typically decohere rapidly from environmental interactions, may persist due to dark matter's infrequent interactions. In this work, I describe the decoherence of these states by gravitational interactions, considering Newtonian gravity and General Relativity. Axion dark matter superpositions of differing mass distributions may rapidly decohere, while those of the phase of axion oscillations are generally robust to decoherence in nonrelativistic scenarios. Next, new effective theories of the QCD axion are presented, which expand the viable range of axion masses. Coupling the axion to new scalars renders the effective PQ symmetry-breaking scale dynamical, allowing heavier axions to be compatible with the observed dark matter abundance and preventing the overproduction of lighter axions from overclosing the universe. These models are motivated by observational hints, such as anomalous cooling of horizontal branch stars, and by fundamental physics, including the possibility of a lighter axion from GUT-scale physics. Lastly, I study tensions in the measurements of (i) the Hubble rate of expansion of the universe today (H0) and (ii) matter clustering (S8), and I propose a dark sector model to address them. This adds a decaying dark energy and ultra-light axion to ΛCDM, accommodating a larger H0 and a smaller S8 while fitting CMB, BAO, and LSS data. The axion is rooted in particle physics, while the fundamental realization of the decaying dark energy needs further study. In summary, this work explores the behavior of dark matter axions in several contexts, examining the implications for observations and cosmology as a whole.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798379562823Subjects--Topical Terms:

1180318
Theoretical physics.
Subjects--Index Terms:

AxionsIndex Terms--Genre/Form:

554714
Electronic books.

Axions in a Dark Universe : = Dark Matter Behavior and Novel Dynamics Inform Cosmological Observations.
LDR:03426ntm a22004097 4500 001 1144806
005 20240611104923.5
006 m o d
007 cr mn ---uuuuu
008 250605s2023 xx obm 000 0 eng d
020 $a 9798379562823
035 $a (MiAaPQ)AAI30422977
035 $a AAI30422977
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Allali, Itamar J. $3 1469956
245 1 0 $a Axions in a Dark Universe : $b Dark Matter Behavior and Novel Dynamics Inform Cosmological Observations.
264 0 $c 2023
300 $a 1 online resource (269 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-11, Section: B.
500 $a Advisor: Hertzberg, Mark P.
502 $a Thesis (Ph.D.)--Tufts University, 2023.
504 $a Includes bibliographical references
520 $a Despite its crucial role in cosmology, little is known about the precise nature of dark matter. This work investigates the nature of dark matter, primarily the QCD axion and other axion-like particles, which are motivated from particle physics. First, I explore the possibility of long-lived quantum superpositions of macroscopic dark matter states in the galaxy. Schrodinger cat states, which typically decohere rapidly from environmental interactions, may persist due to dark matter's infrequent interactions. In this work, I describe the decoherence of these states by gravitational interactions, considering Newtonian gravity and General Relativity. Axion dark matter superpositions of differing mass distributions may rapidly decohere, while those of the phase of axion oscillations are generally robust to decoherence in nonrelativistic scenarios. Next, new effective theories of the QCD axion are presented, which expand the viable range of axion masses. Coupling the axion to new scalars renders the effective PQ symmetry-breaking scale dynamical, allowing heavier axions to be compatible with the observed dark matter abundance and preventing the overproduction of lighter axions from overclosing the universe. These models are motivated by observational hints, such as anomalous cooling of horizontal branch stars, and by fundamental physics, including the possibility of a lighter axion from GUT-scale physics. Lastly, I study tensions in the measurements of (i) the Hubble rate of expansion of the universe today (H0) and (ii) matter clustering (S8), and I propose a dark sector model to address them. This adds a decaying dark energy and ultra-light axion to ΛCDM, accommodating a larger H0 and a smaller S8 while fitting CMB, BAO, and LSS data. The axion is rooted in particle physics, while the fundamental realization of the decaying dark energy needs further study. In summary, this work explores the behavior of dark matter axions in several contexts, examining the implications for observations and cosmology as a whole.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
650 4 $a Theoretical physics. $3 1180318
650 4 $a Astrophysics. $3 646223
650 4 $a Quantum physics. $3 1179090
650 4 $a Particle physics. $3 1335339
653 $a Axions
653 $a Concordance
653 $a Cosmology
653 $a Dark matter
653 $a Decoherence
655 7 $a Electronic books. $2 local $3 554714
690 $a 0753
690 $a 0596
690 $a 0599
690 $a 0798
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Tufts University. $b Physics. $3 1469957
773 0 $t Dissertations Abstracts International $g 84-11B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30422977 $z click for full text (PQDT)