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Quantum Gravity
Edited by Baptiste Le Bihan (University of Geneva)
Assistant editor: Enrico Cinti (Università degli Studi di Urbino, University of Geneva)
About this topic
| Summary | Quantum gravity refers to the set of approaches in theoretical physics seeking to unify general relativity and quantum mechanics. Its philosophical implications can be grouped into three subfields. First, the methodology of Quantum Gravity. It explores the frameworks and approaches employed in formulating a coherent theory of quantum gravity. It involves assessing the mathematical models, experimental designs, and theoretical assumptions that guide research in this domain. Second, the epistemology of Quantum Gravity: it addresses questions about the limits of what can be known, the role of observation and measurement in theory confirmation, and the implications of quantum gravity for our understanding of reality. Challenges include dealing with the lack of empirical data and the speculative nature of some theoretical models. Third, the metaphysics of Quantum Gravity: it investigates the metaphysical implications of quantum gravity theories, particularly in light of the possible non-fundamentality of spacetime. |
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Siblings
- Quantum Chemistry (80)
- Quantum Chromodynamics (9)
- Quantum Computation (150)
- Quantum Electrodynamics (175)
- Quantum Field Theory (258)
- Quantum Information (260)
- Quantum Logic (570)
- Quantum Statistical Mechanics (53)
- Quantum Theories, Misc (117)
Contents
303 found
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| 1 — 50 / 303 |
- Time Remains.Sean Gryb & Karim P. Y. Thébault - 2016 - British Journal for the Philosophy of Science 67 (3):663-705.On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of change as relative variation leads to a fundamentally timeless formalism for quantum gravity. Here, we will show how one may avoid this acute ‘problem of time’. Under our view, (...)
- (1 other version)Physics meets philosophy at the planck scale.Craig Callender & Nicholas Huggett - manuscriptThis is the table of contents and first chapter of Physics Meets Philosophy at the Planck Scale (Cambridge University Press, 2001), edited by Craig Callender and Nick Huggett. The chapter discusses the question of why there should be a theory of quantum gravity. We tackle arguments that purport to show that the gravitational field *must* be quantized. We then introduce various programs in quantum gravity and discuss areas where quantum gravity and philosophy seem to have something to say to each (...)
- Quantum Gravity: Time is the Red Herring and Classical Mathematics is the Elephant in the Room.D. A. Ford - manuscriptRemove from this listExport citation
Bookmark - (4 other versions)Out of Nowhere: the 'emergence' of spacetime in string theory.Nick Huggett & Christian Wüthrich - manuscriptThis is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. This chapter analyses the nature and derivation of spacetime topology and geometry according to string theory.
- (4 other versions)Out of Nowhere: duality.Nick Huggett & Christian Wüthrich - manuscriptThis is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www<dot>beyondspacetime<dot>net.) This chapter investigates the meaning and significance of string theoretic dualities, arguing they reveal a surprising physical indeterminateness to spacetime.
- A-Theory, Gedankenexperiments, and Quantum Gravity.Paul Merriam & M. A. Z. Habeeb - manuscriptThis paper proposes a novel theoretical framework for reconciling quantum mechanics with relativity that leads to a theory of quantum gravity by examining the fundamental nature of time. In the first section we argue that it is possible to perform an experiment for oneself in which, with enough ‘internal technology’ it is possible to distinguish between one’s experience of time on the one hand, and one’s thoughts about one’s experience of time on the other hand. The former gives McTaggart's A-series (...)
- Russell's 1927 The Analysis of Matter as the First Book on Quantum Gravity.Said Mikki - manuscriptThe goal of this note is to bring into wider attention the often neglected important work by Bertrand Russell on the foundations of physics published in the late 1920s. In particular, we emphasize how the book The Analysis of Matter can be considered the earliest systematic attempt to unify the modern quantum theory, just emerging by that time, with general relativity. More importantly, it is argued that the idea of what I call Russell space, introduced in Part III of that (...)
- Épistémologie de la gravité quantique.Sfetcu Nicolae - manuscriptLa gravité quantique a nécessité la prise en compte des questions épistémologiques fondamentales, qui peuvent être identifiées en philosophie avec le problème corps-esprit et le problème du libre arbitre . Ces questions ont influencé l'épistémologie de la mécanique quantique sous la forme du « parallélisme psycho-physique » de von Neumann et l'analyse ultérieure de la thèse de Wigner selon laquelle « l'effondrement du paquet d'ondes » se produit dans l'esprit de « l'observateur ». La gravité quantique en cosmologie pose le (...)
- Épistemologie de la gravité quantique canonique - Gravité quantique à boucles.Sfetcu Nicolae - manuscriptDans l'interprétation de la gravité quantique canonique, la gravité apparaît comme une pseudoforce géométrique, elle est réduite à la géométrie espace-temps et devient un simple effet de la courbure de l'espace-temps . Le formalisme canonique ne confirme pas cette interprétation. La relativité générale associe la gravité à l'espace-temps, mais le type d'association n'est pas fixé. La gravité quantique à boucles tente d'unifier la gravité avec les trois autres forces fondamentales en commençant par la relativité et en ajoutant des traits quantiques. (...)
- Approches de l'interprétation de la gravité quantique.Sfetcu Nicolae - manuscriptL'interprétation de Copenhague peut être comprise non seulement comme une interprétation statistique minimale du formalisme quantique pour la fréquence des résultats de mesure, mais aussi comme mettant l'accent sur un domaine classique du système quantique, avec une séparation ferme de celui-ci et une description quantique de la première interprétation. DOI: 10.13140/RG.2.2.28288.87049.
- Quantum mechanics foundations.Bakytzhan Oralbekov - manuscriptGravity remains the most elusive field. Its relationship with the electromagnetic field is poorly understood. Relativity and quantum mechanics describe the aforementioned fields, respectively. Bosons and fermions are often credited with responsibility for the interactions of force and matter. It is shown here that fermions factually determine the gravitational structure of the universe, while bosons are responsible for the three established and described forces. Underlying the relationships of the gravitational and electromagnetic fields is a symmetrical probability distribution of fermions and (...)
- Epistemology of Experimental Gravity - Scientific Rationality.Nicolae Sfetcu - manuscriptThe evolution of gravitational tests from an epistemological perspective framed in the concept of rational reconstruction of Imre Lakatos, based on his methodology of research programmes. Unlike other works on the same subject, the evaluated period is very extensive, starting with Newton's natural philosophy and up to the quantum gravity theories of today. In order to explain in a more rational way the complex evolution of the gravity concept of the last century, I propose a natural extension of the methodology (...)
- Epistemology of Quantum Gravity.Nicolae Sfetcu - manuscriptQuantum gravity has required the consideration of fundamental epistemological questions, which can be identified in philosophy with the mind-body problem and the problem of free will. These questions influenced the epistemology of quantum mechanics in the form of von Neumann's "psycho-physical parallelism" and the subsequent analysis of the thesis by Wigner that "the collapse of the wave packet" occurs in the mind of the "observer". Quantum gravity in cosmology involves the problem of the experimenter's freedom to change local physical conditions, (...)
- Extensions of quantum gravity theories - Final theory and cosmology.Nicolae Sfetcu - manuscriptThe fields of application of general relativity (GR) and quantum field theory (QFT) are different, so most situations require the use of only one of the two theories. The overlaps occur in regions of extremely small size and high mass, such as the black hole or the early universe (immediately after the Big Bang). This conflict is supposed to be solved only by unifying gravity with the other three interactions, to integrate GR and QFT into one theory. At the cosmological (...)
- Epistemology of String Theory in Quantum Gravity.Nicolae Sfetcu - manuscriptIn quantum field theory, the main obstacle is the occurrence of the untreatable infinities in the interactions of the particles due to the possibility of arbitrary distances between the point particles. Strings, as extended objects, provide a better framework, which allows finite calculations. String theory is part of a research program in which point particles in particle physics are replaced by one-dimensional objects called strings. It describes how these strings propagate through space and interact with one another. The purpose of (...)
- Epistemologia gravitației cuantice.Nicolae Sfetcu - manuscriptDin punct de vedere metodologic, atât Newton cât și Einstein, și ulterior Dirac, au susținut fără rezerve principiul simplității matematice în descoperirea noilor legi fizice ale naturii. Lor li s-au alăturat și Poincaré și Weyl. Eduard Prugovecki afirmă că gravitația cuantică a impus luarea în considerare a unor întrebări epistemologice fundamentale, care pot fi identificate în filosofie cu problema minții-corp și cu problema liberului arbitru. Aceste întrebări au influențat epistemologia mecanicii cuantice sub forma "paralelismului psiho-fizic" al lui von Neumann și (...)
- Gravitația cuantică – Euristica și teste gravitaționale.Nicolae Sfetcu - manuscriptÎn încercarea de dezvoltare a unei teorii solide a gravitației cuantice, au existat mai multe programe de cercetare, dintre care unele au căzut în timp în desuetitudine datorită puterii euristice mai mari a altor programe. Testul primordial al oricărei teorii cuantice a gravitației este reproducerea succeselor relativității generale. Aceasta implică reconstrucția geometriei locale din observabilele nelocale. În plus, gravitația cuantică ar trebui să prezică probabilistic topologia la scară largă a Universului, care în curând poate fi măsurabilă, și fenomene la scala (...)
- Epistemologia gravitației cuantice canonice – Gravitația cuantică în bucle.Nicolae Sfetcu - manuscriptÎn interpretarea gravitației cuantice canonice, gravitația apare ca o pseudoforță geometrică, este redusă la geometria spațio-temporală și devine un simplu efect al curburii spațiu-timpului. Relativitatea generală asociază gravitația cu spațiu-timpul, dar tipul de asociere nu este fixat. În locul interpretării geometrice se poate folosi interpretarea câmpului (geometria spațiu-timp este redusă la un câmp gravitațional, respectiv metrica, considerată drept "doar un alt câmp") sau interpretarea egalitară (o identificare conceptuală a gravitației și spațiu-timpului în relativitatea generală. ). Aceste interpretări alternative reduc diferențele (...)
- Heuristics and Tests of Quantum Gravity.Nicolae Sfetcu - manuscriptFor the attempt to create a gravitational quantum theory, there are several research programs, some of which became obsolete over time due to the higher heuristic power of other programs. The primordial test of any quantum theory of gravity is the reproduction of the successes of general relativity. This involves reconstructing the local geometry from the non-local observables. In addition, quantum gravity should probabilistically predict the large-scale topology of the Universe, which may soon be measurable, and phenomena at the Planck (...)
- Epistemology of Canonical Quantum Gravity - Loop Quantum Gravity.Nicolae Sfetcu - manuscriptIn the interpretation of canonical quantum gravity (CQG), gravity appears as a geometric pseudoforce, is reduced to spacetime geometry and becomes a simple effect of spacetime curvature. The scale at which quantum gravitational effects occur is determined by the different physical constants of fundamental physics: h, c and G, which characterize quantum, relativistic and gravitational phenomena. By combining these constants, we obtain the Planck constants at which the effects of quantum gravity must manifest. Loop quantum gravity attempts to unify gravity (...)
- Quantum Gravity in a Laboratory?Nick Huggett, Niels S. Linnemann & Mike D. Schneider - 2023It has long been thought that observing distinctive traces of quantum gravity in a laboratory setting is effectively impossible, since gravity is so much weaker than all the other familiar forces in particle physics. But the quantum gravity phenomenology community today seeks to do the (effectively) impossible, using a challenging novel class of `tabletop' Gravitationally Induced Entanglement (GIE) experiments, surveyed here. The hypothesized outcomes of the GIE experiments are claimed by some (but disputed by others) to provide a `witness' of (...)
- (4 other versions)Out of Nowhere: Spacetime from causality: causal set theory.Christian Wüthrich & Nick Huggett - 2023This is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www<dot>beyondspacetime<dot>net.) This chapter introduces causal set theory and identifies and articulates a 'problem of space' in this theory.
- (4 other versions)Out of Nowhere: Introduction: the emergence of spacetime.Nick Huggett & Christian Wuthrich - 2021This is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www<dot>beyondspacetime<dot>net.) This chapter introduces the problem of emergence of spacetime in quantum gravity. It introduces the main philosophical challenge to spacetime emergence and sketches our preferred solution to it.
- (4 other versions)Out of Nowhere: The emergence of spacetime from causal sets.Christian Wüthrich & Nick Huggett - 2020This is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www<dot>beyondspacetime<dot>net.) This chapter sketches how spacetime emerges in causal set theory and demonstrates how this question is deeply entangled with genuinely philosophical concerns.
- A Philosopher Looks at Non-Commutative Geometry.Nick Huggett - 2018This paper introduces some basic ideas and formalism of physics in non-commutative geometry. My goals are three-fold: first to introduce the basic formal and conceptual ideas of non-commutative geometry, and second to raise and address some philosophical questions about it. Third, more generally to illuminate the point that deriving spacetime from a more fundamental theory requires discovering new modes of `physically salient' derivation.
- What Can We Learn from Stringy Black Holes?Nick Huggett - 2018This paper aims to address conceptual issues concerning black holes in the context of string theory, with the aim of illuminating the ontological unification of gravity and matter, and the interpretation of cosmological models. §1 describes the central concepts of the theory: the fungibility of matter and geometry, and the reduction of gravity and supergravity. The ‘standard’ interpretation presented draws on that implicit in the thinking of many (but not all) string theorists, though made more explicit and systematic than usual. (...)
- Pre-socratic quantum gravity.Gordon Belot & John Earman - unknown - In Craig Callender & Nicholas Huggett (eds.), Physics meets philosophy at the planck scale. pp. 213--55.Physicists who work on canonical quantum gravity will sometimes remark that the general covariance of general relativity is responsible for many of the thorniest technical and conceptual problems in their field.1 In particular, it is sometimes alleged that one can trace to this single source a variety of deep puzzles about the nature of time in quantum gravity, deep disagreements surrounding the notion of ‘observable’ in classical and quantum gravity, and deep questions about the nature of the existence of spacetime (...)
- Quantum spacetime: What do we know?Carlo Rovelli - unknown - In Craig Callender & Nicholas Huggett (eds.), Physics meets philosophy at the planck scale. pp. 101--22.This is a contribution to a book on quantum gravity and philosophy. I discuss nature and origin of the problem of quantum gravity. I examine the knowledge that may guide us in addressing this problem, and the reliability of such knowledge. In particular, I discuss the subtle modification of the notions of space and time engendered by general relativity, and how these might merge into quantum theory. I also present some reflections on methodological questions, and on some general issues in (...)
- Open Systems: Physics, Metaphysics, and Methodology (2025: Oxford University Press).Michael E. Cuffaro & Stephan Hartmann (eds.) - forthcoming - Oxford: Oxford University Press.Remove from this listExport citation Bookmark
- Not the Measurement Problem's Problem: Black Hole Information Loss with Schrödinger's Cat.Saakshi Dulani - forthcoming - Philosophy of Science.Recently, several philosophers and physicists have increasingly noticed the hegemony of unitarity in the black hole information loss discourse and are challenging its legitimacy in the face of the measurement problem. They proclaim that embracing non-unitarity solves two paradoxes for the price of one. Though I share their distaste over the philosophical bias, I disagree with their strategy of still privileging certain interpretations of quantum theory. I argue that information-restoring solutions can be interpretation-neutral because the manifestation of non-unitarity in Hawking's (...)
- Does Quantum Gravity Happen at the Planck Scale?Caspar Jacobs - forthcoming - Philosophy of Physics.The claim that at the so-called Planck scale our current physics breaks down and a new theory of quantum gravity is required is ubiquitous, but the evidence is shakier than the confidence of those assertions warrants. In this paper, I survey five arguments in favour of this claim - based on dimensional analysis, quantum black holes, generalised uncertainty principles, the nonrenormalisability of quantum gravity, and theories beyond the standard model - but find that none of them succeeds. The argument from (...)
- The Time in Thermal Time.Eugene Y. S. Chua - 2024 - Journal for General Philosophy of Science / Zeitschrift für Allgemeine Wissenschaftstheorie.Preparing general relativity for quantization in the Hamiltonian approach leads to the `problem of time,' rendering the world fundamentally timeless. One proposed solution is the `thermal time hypothesis,' which defines time in terms of states representing systems in thermal equilibrium. On this view, time is supposed to emerge thermodynamically even in a fundamentally timeless context. Here, I develop the worry that the thermal time hypothesis requires dynamics -- and hence time -- to get off the ground, thereby running into worries (...)
- Non-spatial matters: On the possibility of non-spatial material objects.Cruz Austin Davis - 2024 - Synthese 204 (2):1-29.While there is considerable disagreement on the precise nature of material objecthood, it is standardly assumed that material objects must be spatial. In this paper, I provide two arguments against this assumption. The first argument is made from largely a priori considerations about modal plenitude. The possibility of non-spatial material objects follows from commitment to certain plausible principles governing material objecthood and plausible principles regarding modal plenitude. The second argument draws from current philosophical discussions regarding theories of quantum gravity and (...)
- Causal Theories of Spacetime.Sam Baron & Baptiste Le Bihan - 2023 - Noûs 58 (1):202-224.We develop a new version of the causal theory of spacetime. Whereas traditional versions of the theory seek to identify spatiotemporal relations with causal relations, the version we develop takes causal relations to be the grounds for spatiotemporal relations. Causation is thus distinct from, and more basic than, spacetime. We argue that this non-identity theory, suitably developed, avoids the challenges facing the traditional identity theory.
- The many problems of spacetime emergence in quantum gravity.Rasmus Jaksland & Kian Salimkhani - 2023 - British Journal for the Philosophy of Science.In this paper, we argue that what is often discussed under the umbrella of `spacetime emergence' in the philosophy of quantum gravity in fact consists of a plethora of distinct and even highly different problems. We therefore advocate to cast such debates more specifically in terms of the emergent spatiotemporal aspects, as is already done in the physics literature. We first show how ambiguous the notion of spacetime is already in general relativity. We then argue against three ways to reject (...)
- The Non-Fundamentality of Spacetime. General Relativity, Quantum Gravity, and Metaphysics.Kian Salimkhani - 2023 - New York/London: Routledge.This book argues that our current best theories of fundamental physics are best interpreted as positing spacetime as non-fundamental. It is written in accessible language and largely avoids mathematical technicalities by instead focusing on the key metaphysical and foundational lessons for the fundamentality of spacetime. -/- According to orthodoxy, spacetime and spatiotemporal properties are regarded as fundamental structures of our world. Spacetime fundamentalism, however, faces challenges from speculative theories of quantum gravity – roughly speaking, the project of applying the lessons (...)
- On Efforts to Decouple Early Universe Cosmology and Quantum Gravity Phenomenology.Mike D. Schneider - 2023 - Foundations of Physics 53 (4):1-15.The Big Bang singularity in standard model cosmology suggests a program of study in ‘early universe’ quantum gravity phenomenology. Inflation is usually thought to undermine this program’s prospects by means of a dynamical diluting argument, but such a view has recently been disputed within inflationary cosmology, in the form of a ‘trans-Planckian censorship’ conjecture. Meanwhile, trans-Planckian censorship has been used outside of inflationary cosmology to motivate alternative early universe scenarios that are tightly linked to ongoing theorizing in quantum gravity. Against (...)
- New Quantum Spin Perspective of Quantum Gravity and Space-Time of Mind-Stuff.Rakshit Vyas & Mihir Joshi - 2023 - Journal of Applied Consciousness Studies 11 (2):112-19.The fundamental building block of the loop quantum gravity (LQG) is the spin network which is used to quantize the physical space-time in the LQG. Recently, the novel quantum spin is proposed using the basic concepts of the spin network. This perspective redefines the notion of the quantum spin and also introduces the novel definition of the reduced Planck constant. The implication of this perspective is not only limited to the quantum gravity; but also found in the quantum mechanics. Using (...)
- Tabletop Experiments for Quantum Gravity Are Also Tests of the Interpretation of Quantum Mechanics.Emily Adlam - 2022 - Foundations of Physics 52 (5):1-43.Recently there has been a great deal of interest in tabletop experiments intended to exhibit the quantum nature of gravity by demonstrating that it can induce entanglement. In order to evaluate these experiments, we must determine if there is any interesting class of possibilities that will be convincingly ruled out if it turns out that gravity can indeed induce entanglement. In particular, since one argument for the significance of these experiments rests on the claim that they demonstrate the existence of (...)
- Gravitational decoherence: A thematic overview.C. Anastopoulos & B. L. Hu - 2022 - AVS Quantum Science 4:015602.Gravitational decoherence (GD) refers to the effects of gravity in actuating the classical appearance of a quantum system. Because the underlying processes involve issues in general relativity (GR), quantum field theory (QFT), and quantum information, GD has fundamental theoretical significance. There is a great variety of GD models, many of them involving physics that diverge from GR and/or QFT. This overview has two specific goals along with one central theme:(i) present theories of GD based on GR and QFT and explore (...)
- (1 other version)Spacetime Quietism in Quantum Gravity.Sam Baron & Baptiste Le Bihan - 2022 - In Antonio Vassallo (ed.), The Foundations of Spacetime Physics: Philosophical Perspectives. New York, NY: Routledge. pp. 155-175.The existence and fundamentality of spacetime has been questioned in quantum gravity where spacetime is frequently described as emerging from a more fundamental non-spatiotemporal ontology. This is supposed to lead to various philosophical issues such as the problem of empirical coherence. Yet those issues assume beforehand that we actually understand and agree on the nature of spacetime. Reviewing popular conceptions of spacetime, we find that there is substantial disagreement on this matter, and little hope of resolving it. However, we argue (...)
- Composing Spacetime.Sam Baron & Baptiste Le Bihan - 2022 - Journal of Philosophy 119 (1):33-54.According to a number of approaches in theoretical physics, spacetime does not exist fundamentally. Rather, spacetime exists by depending on another, more fundamental, non-spatiotemporal structure. A prevalent opinion in the literature is that this dependence should not be analyzed in terms of composition. We should not say, that is, that spacetime depends on an ontology of non-spatiotemporal entities in virtue of having them as parts. But is that really right? On the contrary, we argue that a mereological approach to dependent (...)
- Jácome (Jay) Armas (ed.): Review of “Conversations on Quantum Gravity”: Cambridge University Press, 2021. [REVIEW]Alexander S. Blum - 2022 - Foundations of Physics 52 (1):1-4.
- Towards ψ-epistemic quantum gravity.Marcoen J. T. F. Cabbolet - 2022 - In And now for something completely different: the Elementary Process Theory. Revised, updated and extended 2nd edition of the dissertation with almost the same title. Utrecht: Eburon Academic Publishers. pp. 288-311.This self-contained letter shows how ψ-epistemic quantum gravity (QG), that is, QG with a ψ-epistemic interpretation of quantum theory, in principle obtains from a deterministic model of the Elementary Process Theory (EPT) that describes an individual process at supersmall (Planck) scale by which a predominantly gravitational interaction takes place. While both ψ-epistemic QG and the model of the EPT remain to be formulated rigorously, this shows how the probabilistic nature of our knowledge of the physical world emerges in a strictly (...)
- Four Attitudes Towards Singularities in the Search for a Theory of Quantum Gravity.Karen Crowther & Sebastian De Haro - 2022 - In Antonio Vassallo (ed.), The Foundations of Spacetime Physics: Philosophical Perspectives. New York, NY: Routledge. pp. 223-250.Singularities in general relativity and quantum field theory are often taken not only to motivate the search for a more-fundamental theory (quantum gravity, QG), but also to characterise this new theory and shape expectations of what it is to achieve. Here, we first evaluate how particular types of singularities may suggest an incompleteness of current theories. We then classify four different 'attitudes' towards singularities in the search for QG, and show, through examples in the physics literature, that these lead to (...)
- Spacetime "Emergence".Nick Huggett - 2022 - In Eleanor Knox & Alastair Wilson (eds.), The Routledge Companion to Philosophy of Physics. London, UK: Routledge.Could spacetime be derived rather than fundamental? The question is pressing because attempts to quantize gravity have led to theories in which (arguably) there are either no, or only extremely thin, spacetime structures. Moreover, recent proposals for the interpretation of quantum mechanics have suggested that 3-dimensional space may be an ‘appearance’ derived from the 3N-dimensional space in which an N-particle wavefunction lives (cross- reference). In fact, I will largely assume a positive answer, and investigate how it could be; in particular, (...)
- Quantum metaphysics and the foundations of spacetime.Vincent Lam, Laurie Letertre & Cristian Mariani - 2022 - In Antonio Vassallo (ed.), The Foundations of Spacetime Physics: Philosophical Perspectives. New York, NY: Routledge.The main research programs in quantum gravity tend to suggest in one way or another that most spacetime structures are not fundamental. At the same time, work in quantum foundations highlights fundamental features that are in tension with any straightforward space- time understanding. This paper aims to explore the little investigated but potentially fruitful links between these two fields.
- TGFT condensate cosmology as an example of spacetime emergence in quantum gravity.Daniele Oriti - 2022 - In Antonio Vassallo (ed.), The Foundations of Spacetime Physics: Philosophical Perspectives. New York, NY: Routledge.Remove from this listExport citation Bookmark
- On momentum operators given by Killing vectors whose integral curves are geodesics.Thomas Schürmann - 2022 - Physics 4 (4): 1440-1452.We consider momentum operators on intrinsically curved manifolds. Given that the momentum operators are Killing vector fields whose integral curves are geodesics, it is shown that the corresponding manifold is either flat, or otherwise of compact type with positive constant sectional curvature and dimension equal to 1, 3 or 7. Explicit representations of momentum operators and the associated Casimir element will be discussed for the 3-sphere. It will be verified that the structure constants of the underlying Lie algebra are proportional (...)
- The Common Logic of Quantum Universe—Part II: The Case of Quantum Gravity.Massimo Tessarotto & Claudio Cremaschini - 2022 - Foundations of Physics 52 (2):1-37.The logical structure of quantum gravity is addressed in the framework of the so-called manifestly covariant approach. This permits to display its close analogy with the logics of quantum mechanics. More precisely, in QG the conventional 2-way principle of non-contradiction holding in Classical Mechanics is shown to be replaced by a 3-way principle. The third state of logical truth corresponds to quantum indeterminacy/undecidability, i.e., the occurrence of quantum observables with infinite standard deviation. The same principle coincides, incidentally, with the earlier (...)
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