The Tao of It and Bit
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Stephen Hawking (1942–2018) World-Renowned Physicist Who Defied the Odds
COMMENT OBITUARY Stephen Hawking (1942–2018) World-renowned physicist who defied the odds. hen Stephen Hawking was speech synthesizer processed his words and diagnosed with motor-neuron generated the androidal accent that became disease at the age of 21, it wasn’t his trademark. In this way, he completed his Wclear that he would finish his PhD. Against best-selling book A Brief History of Time all expectations, he lived on for 55 years, (Bantam, 1988), which propelled him to becoming one of the world’s most celebrated celebrity status. IAN BERRY/MAGNUM scientists. Had Hawking achieved equal distinction Hawking, who died on 14 March 2018, was in any other branch of science besides cos- born in Oxford, UK, in 1942 to a medical- mology, it probably would not have had the researcher father and a philosophy-graduate same resonance with a worldwide public. As mother. After attending St Albans School I put it in The Telegraph newspaper in 2007, near London, he earned a first-class degree “the concept of an imprisoned mind roaming in physics from the University of Oxford. He the cosmos” grabbed people’s imagination. began his research career in 1962, enrolling In 1965, Stephen married Jane Wilde. as a graduate student in a group at the Uni- After 25 years of marriage, and three versity of Cambridge led by one of the fathers children, the strain of Stephen’s illness of modern cosmology, Dennis Sciama. and of sharing their home with a team of The general theory of relativity was at that nurses became too much and they sepa- time undergoing a renaissance, initiated in rated, divorcing in 1995. -
God and Contrasting Interpretations of Quantum Theory
S & CB (2005), 17, 155–175 0954–4194 ROGER PAUL Relative State or It-from-Bit: God and Contrasting Interpretations of Quantum Theory In this article I explore theological implications of two contrasting interpretations of quantum theory: the Relative State interpretation of Hugh Everett III, and the It-from-Bit proposal of John A. Wheeler. The Relative State interpretation considers the Universal Wave Function to be a complete description of reality. Measurement results in a branching process that can be interpreted in terms of many worlds or many minds. I discuss issues of the identity of observers in a branching universe, the ways God may interact with the deterministic, isolated quantum universe and the relative nature of salvation history from a perspective within a branch. In contrast, irreversible, elementary acts of observation are considered to be the foundation of reality in the It-from-Bit proposal. Information gained through observer-participancy (the ‘bits’) constructs the fabric of the physical universe (‘it’), in a self-excited circuit. I discuss whether meaning, including religious faith, is a human construct, and whether creation is co- creation, in which divine power and supremacy are limited by the emergence of a participatory universe. By taking these two contrasting interpretations of quantum theory seriously, I hope to show that the interpretation of quantum mechanics we start from matters theologically. Key words: Quantum theory, theology, relative state, many worlds, it-from- bit, observer-participancy, human identity, divine simplicity, co-creation, salvation history. Theological thinking about quantum mechanics has tended to focus on the issue of Special Divine Action in relation to the uncertainty principle and quan- tum measurement.1 Inevitably, this work has been inconclusive, but has nev- ertheless succeeded in opening up the discussion. -
Life and Quantum Interconnectedness
Life and Quantum Interconnectedness Husin Alatas Theoretical Physics Division, Department of Physics, Faculty of Mathematics and Natural Sciences, IPB University; Center for Transdisciplinary and Sustainability Sciences, IPB University Presented at the Afternoon Discussion on Redesigning the Future (ADReF), CTSS-IPB University, June 30th 2020 Outline... Structure of Fundamental Matter Quantum World and its Weirdness Quantum Interpretations Life and Quantum Interconnectedness Disclaimer!… I am a theoretical physicist, not a philosopher… I have been trained as a reductionist, but now I am trying to be an integralist… Physics… Mainly about understanding nature phenomena based on OBSERVATION and MEASUREMENT conducted through scientific method Theoretical Physics?… Theoretical physics is a branch of physics that deals with rationalization, explanation, and prediction of phenomena in natural systems which is developed based on the combination of mathematics, abstraction, imagination, and intuition. Conducted research mainly based on curiosity with sky as its limit. Albert Einstein… “Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution”… Albert Szent-Györgyi… “As scientists attempt to understand a living system, they move down from dimension to dimension, from one level of complexity to the next lower level. I followed this course in my own studies. I went from anatomy to the study of tissues, then to electron microscopy and chemistry, and finally to quantum mechanics. This downward journey through the scale of dimensions has its irony, for in my search for the secret of life, I ended up with atoms and electrons, which have no life at all. Somewhere along the line life has run out through my fingers. -
Black Hole Entropy, the Black Hole Information Paradox, and Time Travel Paradoxes from a New Perspective
Black hole entropy, the black hole information paradox, and time travel paradoxes from a new perspective Roland E. Allen Physics and Astronomy Department, Texas A&M University, College Station, TX USA [email protected] 1 Black hole entropy, the black hole information paradox, and time travel paradoxes from a new perspective Relatively simple but apparently novel ways are proposed for viewing three related subjects: black hole entropy, the black hole information paradox, and time travel paradoxes. (1) Gibbons and Hawking have completely explained the origin of the entropy of all black holes, including physical black holes – nonextremal and in 3-dimensional space – if one can identify their Euclidean path integral with a true thermodynamic partition function (ultimately based on microstates). An example is provided of a theory containing this feature. (2) There is unitary quantum evolution with no loss of information if the detection of Hawking radiation is regarded as a measurement process within the Everett interpretation of quantum mechanics. (3) The paradoxes of time travel evaporate when exposed to the light of quantum physics (again within the Everett interpretation), with quantum fields properly described by a path integral over a topologically nontrivial but smooth manifold. Keywords: Black hole entropy, information paradox, time travel 1. Introduction The three issues considered in this paper have all been thoroughly discussed by many of the best theorists for several decades, in hundreds of extremely erudite articles and a large number of books. Here we wish to add to the discussion with some relatively simple but apparently novel ideas that involve, first, the interpretation of the Euclidean path integral as a true thermodynamic partition function, and second, the Everett interpretation of quantum mechanics. -
The Rebirth of Cosmology: from the Static to the Expanding Universe
Physics Before and After Einstein 129 M. Mamone Capria (Ed.) IOS Press, 2005 © 2005 The authors Chapter 6 The Rebirth of Cosmology: From the Static to the Expanding Universe Marco Mamone Capria Among the reasons for the entrance of Einstein’s relativity into the scientific folklore of his and our age one of the most important has been his fresh and bold approach to the cosmological problem, and the mysterious, if not paradoxical concept of the universe as a three-dimensional sphere. Einstein is often credited with having led cosmology from philosophy to science: according to this view, he made it possible to discuss in the pro- gressive way typical of science what had been up to his time not less “a field of endless struggles” than metaphysics in Kant’s phrase. It is interesting to remember in this connection that the German philosopher, in his Critique of Pure Reason, had famously argued that cosmology was beyond the scope of science (in the widest sense), being fraught with unsolvable contradictions, inherent in the very way our reason functions. Of course not everybody had been impressed by this argument, and several nineteenth-century scientists had tried to work out a viable image of the universe and its ultimate destiny, using Newtonian mechanics and the principles of thermodynamics. However, this approach did not give unambiguous answers either; for instance, the first principle of thermodynamics was invoked to deny that the universe could have been born at a certain moment in the past, and the second principle to deny that its past could be infinite. -
The Emergence of Gravitational Wave Science: 100 Years of Development of Mathematical Theory, Detectors, Numerical Algorithms, and Data Analysis Tools
BULLETIN (New Series) OF THE AMERICAN MATHEMATICAL SOCIETY Volume 53, Number 4, October 2016, Pages 513–554 http://dx.doi.org/10.1090/bull/1544 Article electronically published on August 2, 2016 THE EMERGENCE OF GRAVITATIONAL WAVE SCIENCE: 100 YEARS OF DEVELOPMENT OF MATHEMATICAL THEORY, DETECTORS, NUMERICAL ALGORITHMS, AND DATA ANALYSIS TOOLS MICHAEL HOLST, OLIVIER SARBACH, MANUEL TIGLIO, AND MICHELE VALLISNERI In memory of Sergio Dain Abstract. On September 14, 2015, the newly upgraded Laser Interferometer Gravitational-wave Observatory (LIGO) recorded a loud gravitational-wave (GW) signal, emitted a billion light-years away by a coalescing binary of two stellar-mass black holes. The detection was announced in February 2016, in time for the hundredth anniversary of Einstein’s prediction of GWs within the theory of general relativity (GR). The signal represents the first direct detec- tion of GWs, the first observation of a black-hole binary, and the first test of GR in its strong-field, high-velocity, nonlinear regime. In the remainder of its first observing run, LIGO observed two more signals from black-hole bina- ries, one moderately loud, another at the boundary of statistical significance. The detections mark the end of a decades-long quest and the beginning of GW astronomy: finally, we are able to probe the unseen, electromagnetically dark Universe by listening to it. In this article, we present a short historical overview of GW science: this young discipline combines GR, arguably the crowning achievement of classical physics, with record-setting, ultra-low-noise laser interferometry, and with some of the most powerful developments in the theory of differential geometry, partial differential equations, high-performance computation, numerical analysis, signal processing, statistical inference, and data science. -
1 Clifford Algebraic Computational Fluid Dynamics
Clifford Algebraic Computational Fluid Dynamics: A New Class of Experiments. Dr. William Michael Kallfelz 1 Lecturer, Department of Philosophy & Religion, Mississippi State University The Philosophy of Scientific Experimentation: A Challenge to Philosophy of Science-Center for Philosophy of Science, University of Pittsburgh October 15-16, 2010. October 24, 2010 Abstract Though some influentially critical objections have been raised during the ‘classical’ pre- computational simulation philosophy of science (PCSPS) tradition, suggesting a more nuanced methodological category for experiments 2, it safe to say such critical objections have greatly proliferated in philosophical studies dedicated to the role played by computational simulations in science. For instance, Eric Winsberg (1999-2003) suggests that computer simulations are methodologically unique in the development of a theory’s models 3 suggesting new epistemic notions of application. This is also echoed in Jeffrey Ramsey’s (1995) notions of “transformation reduction,”—i.e., a notion of reduction of a more highly constructive variety. 4 Computer simulations create a broadly continuous arena spanned by normative and descriptive aspects of theory-articulation, as entailed by the notion of transformation reductions occupying a continuous region demarcated by Ernest Nagel’s (1974) logical-explanatory “domain-combining reduction” on the one hand, and Thomas Nickels’ (1973) heuristic “domain- preserving reduction,” on the other. I extend Winsberg’s and Ramsey’s points here, by arguing that in the field of computational fluid dynamics (CFD) as well as in other branches of applied physics, the computer plays a constitutively experimental role—supplanting in many cases the more traditional experimental methods such as flow- visualization, etc. In this case, however CFD algorithms act as substitutes, not supplements (as the notions “simulation” suggests) when it comes to experimental practices. -
MATTERS of GRAVITY, a Newsletter for the Gravity Community, Number 3
MATTERS OF GRAVITY Number 3 Spring 1994 Table of Contents Editorial ................................................... ................... 2 Correspondents ................................................... ............ 2 Gravity news: Open Letter to gravitational physicists, Beverly Berger ........................ 3 A Missouri relativist in King Gustav’s Court, Clifford Will .................... 6 Gary Horowitz wins the Xanthopoulos award, Abhay Ashtekar ................ 9 Research briefs: Gamma-ray bursts and their possible cosmological implications, Peter Meszaros 12 Current activity and results in laboratory gravity, Riley Newman ............. 15 Update on representations of quantum gravity, Donald Marolf ................ 19 Ligo project report: December 1993, Rochus E. Vogt ......................... 23 Dark matter or new gravity?, Richard Hammond ............................. 25 Conference Reports: Gravitational waves from coalescing compact binaries, Curt Cutler ........... 28 Mach’s principle: from Newton’s bucket to quantum gravity, Dieter Brill ..... 31 Cornelius Lanczos international centenary conference, David Brown .......... 33 Third Midwest relativity conference, David Garfinkle ......................... 36 arXiv:gr-qc/9402002v1 1 Feb 1994 Editor: Jorge Pullin Center for Gravitational Physics and Geometry The Pennsylvania State University University Park, PA 16802-6300 Fax: (814)863-9608 Phone (814)863-9597 Internet: [email protected] 1 Editorial Well, this newsletter is growing into its third year and third number with a lot of strength. In fact, maybe too much strength. Twelve articles and 37 (!) pages. In this number, apart from the ”traditional” research briefs and conference reports we also bring some news for the community, therefore starting to fulfill the original promise of bringing the gravity/relativity community closer together. As usual I am open to suggestions, criticisms and proposals for articles for the next issue, due September 1st. Many thanks to the authors and the correspondents who made this issue possible. -
Arxiv:Gr-Qc/0304042V1 9 Apr 2003
Do black holes radiate? Adam D Helfer Department of Mathematics, Mathematical Sciences Building, University of Missouri, Columbia, Missouri 65211, U.S.A. Abstract. The prediction that black holes radiate due to quantum effects is often considered one of the most secure in quantum field theory in curved space–time. Yet this prediction rests on two dubious assumptions: that ordinary physics may be applied to vacuum fluctuations at energy scales increasing exponentially without bound; and that quantum–gravitational effects may be neglected. Various suggestions have been put forward to address these issues: that they might be explained away by lessons from sonic black hole models; that the prediction is indeed successfully reproduced by quantum gravity; that the success of the link provided by the prediction between black holes and thermodynamics justifies the prediction. This paper explains the nature of the difficulties, and reviews the proposals that have been put forward to deal with them. None of the proposals put forward can so far be considered to be really successful, and simple dimensional arguments show that quantum–gravitational effects might well alter the evaporation process outlined by Hawking. arXiv:gr-qc/0304042v1 9 Apr 2003 Thus a definitive theoretical treatment will require an understanding of quantum gravity in at least some regimes. Until then, no compelling theoretical case for or against radiation by black holes is likely to be made. The possibility that non–radiating “mini” black holes exist should be taken seriously; such holes could be part of the dark matter in the Universe. Attempts to place observational limits on the number of “mini” black holes (independent of the assumption that they radiate) would be most welcome. -
Black Holes and Qubits
Subnuclear Physics: Past, Present and Future Pontifical Academy of Sciences, Scripta Varia 119, Vatican City 2014 www.pas.va/content/dam/accademia/pdf/sv119/sv119-duff.pdf Black Holes and Qubits MICHAEL J. D UFF Blackett Labo ratory, Imperial C ollege London Abstract Quantum entanglement lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the Hawking effect of radiating black holes has also occupied centre stage. Despite their apparent differences, it turns out that there is a correspondence between the two. Introduction Whenever two very different areas of theoretical physics are found to share the same mathematics, it frequently leads to new insights on both sides. Here we describe how knowledge of string theory and M-theory leads to new discoveries about Quantum Information Theory (QIT) and vice-versa (Duff 2007; Kallosh and Linde 2006; Levay 2006). Bekenstein-Hawking entropy Every object, such as a star, has a critical size determined by its mass, which is called the Schwarzschild radius. A black hole is any object smaller than this. Once something falls inside the Schwarzschild radius, it can never escape. This boundary in spacetime is called the event horizon. So the classical picture of a black hole is that of a compact object whose gravitational field is so strong that nothing, not even light, can escape. Yet in 1974 Stephen Hawking showed that quantum black holes are not entirely black but may radiate energy, due to quantum mechanical effects in curved spacetime. In that case, they must possess the thermodynamic quantity called entropy. -
Arxiv:1410.1486V2 [Gr-Qc] 26 Aug 2015
October 2014 Black Hole Thermodynamics S. Carlip∗ Department of Physics University of California Davis, CA 95616 USA Abstract The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many indepen- dent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox. arXiv:1410.1486v2 [gr-qc] 26 Aug 2015 ∗email: [email protected] 1 Introduction The surprising discovery that black holes behave as thermodynamic objects has radically affected our understanding of general relativity and its relationship to quantum field theory. In the early 1970s, Bekenstein [1, 2] and Hawking [3, 4] showed that black holes radiate as black bodies, with characteristic temperatures and entropies ~κ Ahor kTH = ;SBH = ; (1.1) 2π 4~G where κ is the surface gravity and Ahor is the area of the horizon. These quantities appear to be inherently quantum gravitational, in the sense that they depend on both Planck's constant ~ and Newton's constant G. The resulting black body radiation, Hawking radiation, has not yet been directly observed: the temperature of an astrophysical black hole is on the order of a microkelvin, far lower than the cosmic microwave background temperature. But the Hawking temperature and the Bekenstein-Hawking entropy have been derived in so many independent ways, in different settings and with different assumptions, that it seems extraordinarily unlikely that they are not real. -
Arxiv:1202.4545V2 [Physics.Hist-Ph] 23 Aug 2012
The Relativity of Existence Stuart B. Heinrich [email protected] October 31, 2018 Abstract Despite the success of modern physics in formulating mathematical theories that can predict the outcome of experiments, we have made remarkably little progress towards answering the most fundamental question of: why is there a universe at all, as opposed to nothingness? In this paper, it is shown that this seemingly mind-boggling question has a simple logical answer if we accept that existence in the universe is nothing more than mathematical existence relative to the axioms of our universe. This premise is not baseless; it is shown here that there are indeed several independent strong logical arguments for why we should believe that mathematical existence is the only kind of existence. Moreover, it is shown that, under this premise, the answers to many other puzzling questions about our universe come almost immediately. Among these questions are: why is the universe apparently fine-tuned to be able to support life? Why are the laws of physics so elegant? Why do we have three dimensions of space and one of time, with approximate locality and causality at macroscopic scales? How can the universe be non-local and non-causal at the quantum scale? How can the laws of quantum mechanics rely on true randomness? 1 Introduction can seem astonishing that anything exists” [73, p.24]. Most physicists and cosmologists are equally perplexed. Over the course of modern history, we have seen advances in Richard Dawkins has called it a “searching question that biology, chemistry, physics and cosmology that have painted rightly calls for an explanatory answer” [26, p.155], and Sam an ever-clearer picture of how we came to exist in this uni- Harris says that “any intellectually honest person will admit verse.