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A Caltech Library Repository Feedhttp://www.rssboard.org/rss-specificationpython-feedgenenTue, 16 Apr 2024 15:05:29 +0000A Quest for the Physics Beyond the Cosmological Standard Model
https://resolver.caltech.edu/CaltechETD:etd-08252009-151953
Authors: {'items': [{'email': 'lotty@theory.caltech.edu', 'id': 'Ackerman-Mayer-Lotty', 'name': {'family': 'Ackerman Mayer', 'given': 'Lotty'}, 'show_email': 'NO'}]}
Year: 2010
DOI: 10.7907/F0TW-C269
<p>Recent advances in observational cosmology have culminated in the establishment of the cosmological standard model. In spite of this remarkable achievement, the underlying physics remains unknown.</p>
<p>In this thesis we propose models whose predictions can be compared with observations, and can thereby help us discover this as-yet unknown physics of the Universe. We examine (i) the consequences that a preferred direction during the inflationary era would have on the Cosmic Microwave Background (CMB) anisotropies, (ii) the effect of asymmetric beams in the Wilkinson Microwave Anisotropy Probe (WMAP), (iii) astrophysical consequences of a dark photon that couples only to dark matter, and (iv) explore a mechanism for producing density perturbations during the period of reheating.</p>
https://thesis.library.caltech.edu/id/eprint/5277An Investigation of Spontaneous Lorentz Violation and Cosmic Inflation
https://resolver.caltech.edu/CaltechTHESIS:05262010-182408575
Authors: {'items': [{'email': 'heywood_tam@hotmail.com', 'id': 'Tam-Heywood', 'name': {'family': 'Tam', 'given': 'Heywood'}, 'show_email': 'YES'}]}
Year: 2010
DOI: 10.7907/8BH2-F266
<p>In this thesis we re-examine two established ideas in theoretical physics: Lorentz invariance and cosmic inflation.</p>
<p>In the first four chapters, we (i) propose a way to hide large extra dimensions by coupling standard model fields with Lorentz-violating tensor fields with expectation values along the extra dimensions; (ii) examine the stability of theories in which Lorentz invariance is spontaneously broken by fixed-norm `aether' fields; (iii) investigate the phenomenological properties of the sigma-model aether theory; and (iv) explore the implications of an alternative theory of gravity in which the graviton arises from the Goldstone modes of a two-index symmetric aether field.</p>
<p>In the final chapter, we examine the horizon and flatness problems using the canonical measure (developed by Gibbons, Hawking, and Stewart) on the space of solutions to Einstein's equations. We find that the flatness problem does not exist, while the homogeneity of our universe does represent a substantial fine-tuning. Based on the assumption of unitary evolution (Liouville's theorem), we further dispute the widely accepted claim that inflation makes our universe more natural.</p> https://thesis.library.caltech.edu/id/eprint/5851Investigations into the Conditions Necessary for Stochastic Eternal Inflation
https://resolver.caltech.edu/CaltechTHESIS:02132018-124239126
Authors: {'items': [{'id': 'Kuns-Kevin-Aaron', 'name': {'family': 'Kuns', 'given': 'Kevin Aaron'}, 'show_email': 'NO'}]}
Year: 2012
DOI: 10.7907/VA85-YW36
Theories of cosmological inflation, an early exponential expansion of the universe, have solved the
horizon, flatness, and monopole problems in addition to successfully predicting properties of the
fluctuations in the cosmic microwave background. Many of these theories have the property, known as
eternal inflation, where inflation never ends everywhere at the same time and where there are always
regions of exponentially expanding inflating space. The details of inflation are not known at this
time and it would be interesting to estimate how generic eternal inflation is in the space of possible
inflaton potentials. Of the several ways that inflation can be eternal, we focus here on the one, known
as stochastic eternal inflation, where inflation is prevented from ending everywhere by quantum
fluctuations in the inflaton field exceeding its classical motion. We argue that the conditions currently
used to classify a trajectory as stochastically eternal are inadequate for general trajectories where the
inflaton field may classically have a large velocity or be moving up its potential and are therefore illsuited
to studying how generic stochastic eternal inflation is. We propose an improved condition that
takes these possibilities into account as well as more accurately calculating the quantum fluctuations
using a perturbative Langevin method developed elsewhere. We investigate this condition in specific
inflaton potentials and find examples where this condition deviates significantly from the one usually
used in addition to finding examples where the mechanisms for eternal inflation are seemingly met
even though space is not inflating.https://thesis.library.caltech.edu/id/eprint/10710Deviation from Standard Inflationary Cosmology and the Problems in Ekpyrosis
https://resolver.caltech.edu/CaltechTHESIS:03212013-213920050
Authors: {'items': [{'email': 'chienyao.tseng@gmail.com', 'id': 'Tseng-Chien-Yao', 'name': {'family': 'Tseng', 'given': 'Chien-Yao'}, 'show_email': 'NO'}]}
Year: 2013
DOI: 10.7907/KAHC-PK38
There are two competing models of our universe right now. One is Big Bang with inflation cosmology. The other is the cyclic model with ekpyrotic phase in each cycle. This paper is divided into two main parts according to these two models. In the first part, we quantify the potentially observable effects of a small violation of translational invariance during inflation, as characterized by the presence of a preferred point, line, or plane. We explore the imprint such a violation would leave on the cosmic microwave background anisotropy, and provide explicit formulas for the expected amplitudes ⟨a<sub>lm</sub>a<sub>l'm'</sub><sup>*</sup>⟩ of the spherical-harmonic coefficients. We then provide a model and study the two-point correlation of a massless scalar (the inflaton) when the stress tensor contains the energy density from an infinitely long straight cosmic string in addition to a cosmological constant. Finally, we discuss if inflation can reconcile with the Liouville's theorem as far as the fine-tuning problem is concerned. In the second part, we find several problems in the cyclic/ekpyrotic cosmology. First of all, quantum to classical transition would not happen during an ekpyrotic phase even for superhorizon modes, and therefore the fluctuations cannot be interpreted as classical. This implies the prediction of scale-free power spectrum in ekpyrotic/cyclic universe model requires more inspection. Secondly, we find that the usual mechanism to solve fine-tuning problems is not compatible with eternal universe which contains infinitely many cycles in both direction of time. Therefore, all fine-tuning problems including the flatness problem still asks for an explanation in any generic cyclic models.
https://thesis.library.caltech.edu/id/eprint/7547Cosmological Consequences of Dark Matter Interactions and Vacuum Fluctuations
https://resolver.caltech.edu/CaltechTHESIS:05302014-163148727
Authors: {'items': [{'email': 'kboddy@gmail.com', 'id': 'Boddy-Kimberly-K', 'name': {'family': 'Boddy', 'given': 'Kimberly K.'}, 'show_email': 'NO'}]}
Year: 2014
DOI: 10.7907/9YN7-RS46
<p>This thesis is divided into two parts: interacting dark matter and fluctuations in cosmology. There is an incongruence between the properties that dark matter is expected to possess between the early universe and the late universe. Weakly-interacting dark matter yields the observed dark matter relic density and is consistent with large-scale structure formation; however, there is strong astrophysical evidence in favor of the idea that dark matter has large self-interactions. The first part of this thesis presents two models in which the nature of dark matter fundamentally changes as the universe evolves. In the first model, the dark matter mass and couplings depend on the value of a chameleonic scalar field that changes as the universe expands. In the second model, dark matter is charged under a hidden SU(N) gauge group and eventually undergoes confinement. These models introduce very different mechanisms to explain the separation between the physics relevant for freezeout and for small-scale dynamics.</p>
<p>As the universe continues to evolve, it will asymptote to a de Sitter vacuum phase. Since there is a finite temperature associated with de Sitter space, the universe is typically treated as a thermal system, subject to rare thermal fluctuations, such as Boltzmann brains. The second part of this thesis begins by attempting to escape this unacceptable situation within the context of known physics: vacuum instability induced by the Higgs field. The vacuum decay rate competes with the production rate of Boltzmann brains, and the cosmological measures that have a sufficiently low occurrence of Boltzmann brains are given more credence. Upon further investigation, however, there are certain situations in which de Sitter space settles into a quiescent vacuum with no fluctuations. This reasoning not only provides an escape from the Boltzmann brain problem, but it also implies that vacuum states do not uptunnel to higher-energy vacua and that perturbations do not decohere during slow-roll inflation, suggesting that eternal inflation is much less common than often supposed. Instead, decoherence occurs during reheating, so this analysis does not alter the conventional understanding of the origin of density fluctuations from primordial inflation.</p>https://thesis.library.caltech.edu/id/eprint/8447Probability in Quantum Mechanics: The Everett Interpretation and the Decision-Theoretic Program
https://resolver.caltech.edu/CaltechTHESIS:02252016-140043335
Authors: {'items': [{'id': 'Chua-Meng-Shuen', 'name': {'family': 'Chua', 'given': 'Meng Shuen'}, 'show_email': 'NO'}]}
Year: 2015
DOI: 10.7907/5YR6-V715
The Everett interpretation of quantum mechanics is an increasingly popular alternative to the
traditional Copenhagen interpretation, but there are a few major issues that prevent the widespread
adoption. One of these issues is the origin of probabilities in the Everett interpretation, which this
thesis will attempt to survey. The most successful resolution of the probability problem thus far is the
decision-theoretic program, which attempts to frame probabilities as outcomes of rational decision
making. This marks a departure from orthodox interpretations of probabilities in the physical
sciences, where probabilities are thought to be objective, stemming from symmetry considerations.
This thesis will attempt to offer evaluations on the decision-theoretic program.https://thesis.library.caltech.edu/id/eprint/9587Defining Gravity: Effective Field Theory, Entanglement, and Cosmology
https://resolver.caltech.edu/CaltechTHESIS:04072017-131612641
Authors: {'items': [{'id': 'Remmen-Grant-Newton', 'name': {'family': 'Remmen', 'given': 'Grant Newton'}, 'orcid': '0000-0001-6569-8866', 'show_email': 'NO'}]}
Year: 2017
DOI: 10.7907/Z90R9MD1
<p>Many of the most exciting open problems in high-energy physics are related to the behavior and ultimate nature of gravity and spacetime. In this dissertation, several categories of new results in quantum and classical gravity are presented, with applications to our understanding of both quantum field theory and cosmology.</p>
<p>A fundamental open question in quantum field theory is related to ultraviolet completion: Which low-energy effective field theories can be consistently combined with quantum gravity? A celebrated example of the swampland program---the investigation of this question---is the weak gravity conjecture, which mandates, for a U(1) gauge field coupled consistently to gravity, the existence of a state with charge-to-mass ratio greater than unity. In this thesis, we demonstrate the tension between the weak gravity conjecture and the naturalness principle in quantum field theory, generalize the weak gravity conjecture to multiple gauge fields, and exhibit a model in which the weak gravity conjecture solves the standard model hierarchy problem. Next, we demonstrate that gravitational effective field theories can be constrained by infrared physics principles alone, namely, analyticity, unitarity, and causality. In particular, we derive bounds related to the weak gravity conjecture by placing such infrared constraints on higher-dimension operators in a photon-graviton effective theory. We furthermore place bounds on higher-curvature corrections to the Einstein equations, first using analyticity of graviton scattering amplitudes and later using unitarity of an arbitrary tree-level completion, as well as constrain the couplings in models of massive gravity. Completing our treatment of perturbative quantum gravity, outside of the swampland program, we also reformulate graviton perturbation theory itself, finding a field redefinition and gauge-fixing of the Einstein-Hilbert action that drastically simplifies the Feynman diagram expansion. Furthermore, our reformulation also exhibits a hidden symmetry of general relativity that corresponds to the double copy relations equating gravity amplitudes to sums of squares of gluon amplitudes in Yang-Mills theory, a surprising correspondence that yields insights into the structure of quantum field theories.</p>
<p>Moving beyond perturbation theory into nonperturbative questions in quantum gravity, we consider the deep relation between spacetime geometry and properties of the quantum state. In the context of holography and the anti-de Sitter/conformal field theory correspondence, we test the proposed ER=EPR correspondence equating quantum entanglement with wormholes in spacetime. In particular, we demonstrate that the no-cloning theorem in quantum mechanics and the no-go theorem for topology change of spacetime are dual under the ER=EPR correspondence. Furthermore, we prove that the presence of a wormhole is not an observable in quantum gravity, rescuing ER=EPR from potential violation of linearity of quantum mechanics. Excitingly, we also prove a new area theorem within classical general relativity for arbitrary dynamics of two collections of wormholes and black holes; this area theorem is the ER=EPR analogue of entanglement conservation. We next turn our attention to the emergence of spacetime itself, placing consistency conditions on the proposed correspondence between anti-de Sitter space and the Multiscale Entanglement Renormalization Ansatz, a special tensor network that constitutes a computational tool for finding the ground state of certain quantum systems. Further examining the role of quantum entanglement entropy in the emergence of general relativity, we ask whether there is a consistent microscopic formulation of the entropy in theories of entropic gravity; we find that our results weaken equation-of-state proposals for entropic gravity while strengthening those more akin to holography, guiding future investigation of theories of emergent gravity.</p>
<p>Finally, we examine the consequences of the Hamiltonian constraint in classical gravity for the early universe. The Hamiltonian constraint allows for the Liouville measure on the phase space of cosmological parameters for homogeneous, isotropic universes to be converted into a probability distribution on trajectories, or equivalently, on initial conditions. However, this measure diverges on the set of spacetimes that are spatially flat, like the observable universe. In this thesis, we derive the unique, classical, Hamiltonian-conserved measure for the subset of flat universes. This result allows for distinction between different models of cosmic inflation with similar observable predictions; for example, we find that the measure favors models of large-scale inflation, as such potentials more naturally produce the number of e-folds necessary to match cosmological observations.</p>https://thesis.library.caltech.edu/id/eprint/10132Constraints on Cosmology and Quantum Gravity from Quantum Mechanics and Quantum Field Theory
https://resolver.caltech.edu/CaltechTHESIS:05252017-171005406
Authors: {'items': [{'email': 'jasonpollack@gmail.com', 'id': 'Pollack-Jason-Aaron', 'name': {'family': 'Pollack', 'given': 'Jason Aaron'}, 'orcid': '0000-0003-4754-4905', 'show_email': 'NO'}]}
Year: 2017
DOI: 10.7907/Z9W093ZG
<p>Typical cosmological states have structure, obey to very good approximation the laws of classical physics on large scales, and are far from equilibrium. Typical quantum-mechanical states have none of these properties. If the universe is described by a state in a Hilbert space, the state and its Hilbert space must therefore obey a number of constraints to describe realistic cosmological spacetimes. In particular, they must admit a quantum-to-classical transition via decoherence that allows for the emergence of classical spacetimes, and such spacetimes must obey gravitational constraints, in particular on the entanglement entropy of subsystems within them. The papers collected in this thesis are concerned with these constraints. We investigate two holographic correspondences inspired by AdS/CFT, the AdS-MERA correspondence, which suggests that anti-de~Sitter space may be given a discretized description as a tensor network, and the ER=EPR duality, which identified entangled qubits with wormholes connecting them. In the former case, we use holographic entropy bounds to severely constrain the properties of any such tensor network; in the latter case we prove a new general-relativistic area theorem which states that an area corresponding to the entanglement entropy in wormhole geometries is exactly conserved. We use information-theoretic constraints to show that under mild assumptions about the black hole interior an observer falling beyond the horizon is unable to verify the claimed cloning of information in the firewall paradox before reaching the singularity. Finally, we analyze the decoherence structures of late-time de~Sitter space and early-time slow-roll eternal inflation. We show that in the former case a universe with an infinite-dimensional Hilbert space and a positive cosmological constant inevitably reaches a maximum-entropy state from which no further branching or decoherence is possible, forbidding the existence of dynamical quantum fluctuations at late time. In the latter case, gravitational-strength interaction among inflaton modes leads to decoherence of sufficiently super-Hubble modes, which we argue backreacts to cause different histories of cosmological evolution on different branches and hence creates the conditions necessary for eternal inflation.</p>https://thesis.library.caltech.edu/id/eprint/10209The Union of Quantum Field Theory and Non-Equilibrium Thermodynamics
https://resolver.caltech.edu/CaltechTHESIS:05312018-124004005
Authors: {'items': [{'email': 'abartolo.tb@gmail.com', 'id': 'Bartolotta-Anthony-Leo', 'name': {'family': 'Bartolotta', 'given': 'Anthony Leo'}, 'orcid': '0000-0003-4971-9545', 'show_email': 'NO'}]}
Year: 2018
DOI: 10.7907/F7VT-7X41
<p>Quantum field theory is the language used to describe nature at its most fundamental scales; while thermodynamics is a framework to describe the collective behavior of macroscopic systems. Recent advances in non-equilibrium thermodynamics have enabled this framework to be applied to smaller systems operating out of thermal equilibrium. This thesis is concerned with both quantum field theory and non-equilibrium thermodynamics independently and with their intersection.</p>
<p>First, a purely phenomenological application of quantum field theory is explored in the context of the upcoming Mu2E experiment. This experiment will look for rare decays which would indicate the presence of physics beyond the Standard Model. Using the language of effective field theories, a next-to-leading order analysis of the conversion rate is performed.</p>
<p>The focus then shifts to an apparent paradox in the Bayesian interpretation of statistical mechanics. For a Bayesian observer making measurements of an open system, the Shannon entropy decreases, in apparent violation of the Second Law of Thermodynamics. It is shown that rather than utilizing the entropy, which can decrease under Bayesian updates, the Second Law for a Bayesian observer can be rephrased in terms
of a cross-entropy which is always non-negative.</p>
<p>Finally, the intersection of quantum field theory and non-equilibrium thermodynamics is examined. Using quantum work fluctuation theorems, an investigation of how these frameworks can be applied to a driven quantum field theory is performed. For a time-dependent variant of λφ<sup>4</sup> , analytic expressions for the work distribution functions at one-loop order are derived. These expressions are shown to satisfy the quantum Jarzynski equality and Crooks fluctuation theorem.</p>https://thesis.library.caltech.edu/id/eprint/10981Gravity Informed
https://resolver.caltech.edu/CaltechTHESIS:05282018-130631568
Authors: {'items': [{'email': 'aechatwi@gmail.com', 'id': 'Chatwin-Davies-Aidan-Émile', 'name': {'family': 'Chatwin-Davies', 'given': 'Aidan Émile'}, 'orcid': '0000-0003-1406-9271', 'show_email': 'NO'}]}
Year: 2018
DOI: 10.7907/ZD4W-4C63
<p>Formulating a universally satisfactory theory of quantum gravity is a long-standing open problem in theoretical physics. Relatively recently, the use of techniques from quantum information has emerged as a powerful tool for analyzing phenomena that lie at the intersection of quantum theory and gravitation. This thesis describes several advances and novel proposals that were made regarding information theoretic aspects of quantum gravity in three broad areas: holography, cosmology, and the black hole information problem.</p>
<p>Regarding holography, we first assess the differences between typical holographic states and fully random states. Next, we show that determining Ryu-Takayanagi surfaces in AdS<sub>3</sub>/CFT<sub>2</sub> is computationally easy from a complexity-theoretic standpoint. Finally, we identify precise consistency conditions that constrain the validity of an early tensor network model for the AdS/CFT correspondence that uses the Multiscale Entanglement Renormalization Ansatz (MERA).</p>
<p>Regarding cosmology, we propose an alternative interpretation of the MERA as a discretization of de Sitter spacetime. Next, we return to holographic ideas and show that an appropriately-defined Generalized Second Law implies a cosmic no-hair theorem for certain classes of cosmological spacetimes. Finally, we advance an information-theoretic proposal for calculating the signature of a quantum gravity-motivated, fully covariant, natural ultraviolet cutoff in the spectrum of inflationary perturbations.</p>
<p>Regarding the black hole information problem, we begin by exhibiting a simple protocol which, under highly specific circumstances, allows one to retrieve a single qubit from a black hole. Next, we propose an operational resolution of the black hole information problem in which observers who enter the black hole could never detect an inconsistency between their experiences and quantum mechanics due to the finite amount of time available before reaching the central singularity. Finally, we discuss a proposal to understand the emergence of an ensemble of definite geometries during the process of black hole evaporation as a decoherence process, as well as its implications for the black hole information problem.</p>https://thesis.library.caltech.edu/id/eprint/10954Towards a Theory of Quantum Gravity Through Geometrization of Quantum Mechanics
https://resolver.caltech.edu/CaltechTHESIS:05082018-133854488
Authors: {'items': [{'email': 'ccj991@gmail.com', 'id': 'Cao-ChunJun', 'name': {'family': 'Cao', 'given': 'ChunJun'}, 'orcid': '0000-0002-5761-5474', 'show_email': 'NO'}]}
Year: 2018
DOI: 10.7907/SCD0-VB49
<p>In this thesis, we adapt an approach by assuming quantum mechanics as a fundamental theory of nature and attempt to recover familiar concepts such as space-time geometry and gravity from quantum wavefunctions and their unitary evolutions. More specifically, we explore a number of approaches in "geometrizing" quantum systems using techniques such as tensor networks and manifold learning. We find that consistency conditions in quantum gravity can be used to put constraints on tensor network models that approximate the anti-de Sitter/Conformal Field Theory correspondence. Furthermore, quantum circuits and tensor networks can also be used to describe cosmological models and reproduce important features of space-time configurations such as de Sitter space. We find that a generic framework using quantum circuit to describe cosmology puts an upper bound on the number of e-folds during the inflationary phase of the Universe's expansion. In addition to tensor network models, we also propose a Bulk Entanglement Gravity framework that analyzes the entanglement data of a quantum state in a Hilbert space without any <i>a priori</i> assumptions on geometry, such as the likes of a boundary conformal field theory. We find that from an amorphous configuration, one can directly recover geometry of bulk space-time from a generic class of wavefunctions that is fully characterized in this thesis via quantum entropy cone techniques. We find that under a number of assumptions, it is possible to derive linearized Einstein's equation from a version of Jacobson's entanglement equilibrium conditions for an emergent spacetime geometry in the weak field limit near Minkowski space. We show that non-local entanglement perturbations display features of wormhole-like configurations. We also clarify connections between Bulk Entanglement Gravity and highly generic features in quantum error correction codes that can be used to derive gravity.</p>https://thesis.library.caltech.edu/id/eprint/10860Quantum Mechanical Vistas on the Road to Quantum Gravity
https://resolver.caltech.edu/CaltechTHESIS:05292020-005036817
Authors: {'items': [{'email': 'ashmeet.quark@gmail.com', 'id': 'Singh-Ashmeet', 'name': {'family': 'Singh', 'given': 'Ashmeet'}, 'orcid': '0000-0002-4404-1416', 'show_email': 'YES'}]}
Year: 2020
DOI: 10.7907/m1vx-d174
<p>In this thesis, we lay out the goal, and a broad outline, for a program that takes quantum mechanics in its minimal form to be the fundamental ontology of the universe. Everything else, including features like space-time, matter and gravity associated with classical reality, are emergent from these minimal quantum elements. We argue that the Hilbert space of quantum gravity is locally finite-dimensional, in sharp contrast to that of conventional field theory, which could have observable consequences for gravity. We also treat time and space on an equal footing in Hilbert space in a reparametrization invariant setting and show how symmetry transformations, both global and local, can be treated as unitary basis changes.</p>
<p>Motivated by the finite-dimensional context, we use Generalized Pauli Operators as finite-dimensional conjugate variables and define a purely Hilbert space notion of locality based on the spread induced by conjugate operators which we call "Operator Collimation." We study deviations in the spectrum of physical theories, particularly the quantum harmonic oscillator, induced by finite-dimensional effects, and show that by including a black hole-based bound in a lattice field theory, the quantum contribution to the vacuum energy can be suppressed by multiple orders of magnitude.</p>
<p>We then show how one can recover subsystem structure in Hilbert space which exhibits emergent quasi-classical dynamics. We explicitly connect classical features (such as pointer states of the system being relatively robust to entanglement production under environmental monitoring and the existence of approximately classical trajectories) with features of the Hamiltonian. We develop an in-principle algorithm based on extremization of an entropic quantity that can sift through different factorizations of Hilbert space to pick out the one with manifest classical dynamics. This discussion is then extended to include direct sum decompositions and their compatibility with Hamiltonian evolution.</p>
<p>Following this, we study quantum coarse-graining and state-reduction maps in a broad context. In addition to developing a first-principle quantum coarse-graining algorithm based on principle component analysis, we construct more general state-reduction maps specified by a restricted set of observables which do not span the full algebra (as could be the case of limited access in a laboratory or in various situations in quantum gravity). We also present a general, not inherently numeric, algorithm for finding irreducible representations of matrix algebras.</p>
<p>Throughout the thesis, we discuss implications of our work in the broader goal of understanding quantum gravity from minimal elements in quantum mechanics.</p>https://thesis.library.caltech.edu/id/eprint/13734Energy Non-Conservation in Quantum Mechanics
https://resolver.caltech.edu/CaltechTHESIS:09062020-104208324
Authors: {'items': [{'email': 'jackie.lodman@gmail.com', 'id': 'Lodman-Jackie-Julia', 'name': {'family': 'Lodman', 'given': 'Jackie Julia'}, 'orcid': '0000-0003-0923-9440', 'show_email': 'NO'}]}
Year: 2020
DOI: 10.7907/4a55-jt21
<p>Conservation of energy is an integral component of modern physics, but questions remain in quantum mechanics. In traditional quantum mechanics, superpositions of energy eigenstates collapse into a single energy eigenstate upon measurement, and any change in energy after measurement is thought to be lost/gained in the measurement process. However, we argue that energy non-conservation in quantum mechanics cannot be entirely accounted for by leakage to the apparatus/environment. We first present a comprehensive Hamiltonian where energy is not conserved in any considered interpretation <i>according to an observer</i>. Next, we present a protocol for developing experiments to observe this non-conservation, then we use our protocol to develop an example thought experiment. In both the comprehensive Hamiltonian and thought experiment examples, energy is not conserved <i>to an observer</i> in all considered interpretations, but it is conserved when considering the universe's global wave function in Everettian quantum mechanics. Finally, we discuss implications for the status of conservation of energy and other conservation laws. The work presented in this thesis will be adapted into an upcoming paper, Carroll and Lodman.</p>https://thesis.library.caltech.edu/id/eprint/13866