String Theory and Quantum Geometry
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Quantum Vacuum Energy Density and Unifying Perspectives Between Gravity and Quantum Behaviour of Matter
Annales de la Fondation Louis de Broglie, Volume 42, numéro 2, 2017 251 Quantum vacuum energy density and unifying perspectives between gravity and quantum behaviour of matter Davide Fiscalettia, Amrit Sorlib aSpaceLife Institute, S. Lorenzo in Campo (PU), Italy corresponding author, email: [email protected] bSpaceLife Institute, S. Lorenzo in Campo (PU), Italy Foundations of Physics Institute, Idrija, Slovenia email: [email protected] ABSTRACT. A model of a three-dimensional quantum vacuum based on Planck energy density as a universal property of a granular space is suggested. This model introduces the possibility to interpret gravity and the quantum behaviour of matter as two different aspects of the same origin. The change of the quantum vacuum energy density can be considered as the fundamental medium which determines a bridge between gravity and the quantum behaviour, leading to new interest- ing perspectives about the problem of unifying gravity with quantum theory. PACS numbers: 04. ; 04.20-q ; 04.50.Kd ; 04.60.-m. Key words: general relativity, three-dimensional space, quantum vac- uum energy density, quantum mechanics, generalized Klein-Gordon equation for the quantum vacuum energy density, generalized Dirac equation for the quantum vacuum energy density. 1 Introduction The standard interpretation of phenomena in gravitational fields is in terms of a fundamentally curved space-time. However, this approach leads to well known problems if one aims to find a unifying picture which takes into account some basic aspects of the quantum theory. For this reason, several authors advocated different ways in order to treat gravitational interaction, in which the space-time manifold can be considered as an emergence of the deepest processes situated at the fundamental level of quantum gravity. -
Quantum Geometry and Quantum Field Theory
Quantum Geometry and Quantum Field Theory Robert Oeckl Downing College Cambridge September 2000 A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge Preface This dissertation is based on research done at the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, in the period from October 1997 to August 2000. It is original except where reference is made to the work of others. Chapter 4 in its entirety and Chapter 2 partly (as specified therein) represent work done in collaboration with Shahn Majid. All other chapters represent solely my own work. No part of this dissertation nor anything substantially the same has been submitted for any qualification at any other university. Most of the material presented has been published or submitted for publication in the following papers: [Oec99b] R. Oeckl, Classification of differential calculi on U (b ), classical limits, and • q + duality, J. Math. Phys. 40 (1999), 3588{3603. [MO99] S. Majid and R. Oeckl, Twisting of Quantum Differentials and the Planck Scale • Hopf Algebra, Commun. Math. Phys. 205 (1999), 617{655. [Oec99a] R. Oeckl, Braided Quantum Field Theory, Preprint DAMTP-1999-82, hep- • th/9906225. [Oec00b] R. Oeckl, Untwisting noncommutative Rd and the equivalence of quantum field • theories, Nucl. Phys. B 581 (2000), 559{574. [Oec00a] R. Oeckl, The Quantum Geometry of Spin and Statistics, Preprint DAMTP- • 2000-81, hep-th/0008072. ii Acknowledgements First of all, I would like to thank my supervisor Shahn Majid. Besides helping and encouraging me in my studies, he managed to inspire me with a deep fascination for the subject. -
Of Quantum and Information Theories
LETT]~R~, AL NU0V0 ClMENTO VOL. 38, N. 16 17 Dicembrc 1983 Geometrical . Identification. of Quantum and Information Theories. E. R. CA~A~IET.LO(*) Joint Institute ]or Nuclear Research, Laboratory o/ Theoretical l~hysics - Dubna (ricevuto il 15 Settembre 1983) PACS. 03.65. - Quantum theory; quantum mechanics. Quantum mechanics and information theory both deal with (( phenomena )) (rather than (~ noumena ,) as does classical physics) and, in a way or another, with (( uncertainty ~>, i.e. lack of information. The issue may be far more general, and indeed of a fundamental nature to all science; e.g. recently KALMA~ (1) has shown that (~ uncertain data )~ lead to (~ uncertain models )) and that even the simplest linear models must be profoundly modified when this fact is taken into account (( in all branches of science, including time-series analysis, economic forecasting, most of econometrics, psychometrics and elsewhere, (2). The emergence of (~ discrete levels ~) in every sort of ~( structured sys- tems ~ (a) may point in the same direction. Connections between statistics, quantum mechanics and information theory have been studied in remarkable papers (notably by TRIBUS (4) and JAY~s (s)) based on the maximum (Shannon) entropy principle. We propose here to show that such a connection can be obtained in the (( natural meeting ground ~) of geometry. Information theory and several branches of statistics have classic geometric realizations, in which the role of (( distance ~)is played by the infinitesimal difference between two probability distributions: the basic concept is here cross-entropy, i.e. information (which we much prefer to entropy: the latter is essentially (~ static )~, while the former correlates a posterior to a prior situa- tion and invites thus to dynamics). -
String Phenomenology
Introduction Model Building Moduli Stabilisation Flavour Problem String Phenomenology Joseph Conlon (Oxford University) EPS HEP Conference, Krakow July 17, 2009 Joseph Conlon (Oxford University) String Phenomenology Introduction Model Building Moduli Stabilisation Flavour Problem Chalk and Cheese? Figure: String theory and phenomenology? Joseph Conlon (Oxford University) String Phenomenology Introduction Model Building Moduli Stabilisation Flavour Problem String Theory ◮ String theory is where one is led by studying quantised relativistic strings. ◮ It encompasses lots of areas ( black holes, quantum field theory, quantum gravity, mathematics, particle physics....) and is studied by lots of different people. ◮ This talk is on string phenomenology - the part of string theory that aims at connecting to the Standard Model and its extensions. ◮ It aims to provide a (brief) overview of this area. (cf Angel Uranga’s plenary talk) Joseph Conlon (Oxford University) String Phenomenology Introduction Model Building Moduli Stabilisation Flavour Problem String Theory ◮ For technical reasons string theory is consistent in ten dimensions. ◮ Six dimensions must be compactified. ◮ Ten = (Four) + (Six) ◮ Spacetime = (M4) + Calabi-Yau Space ◮ All scales, matter, particle spectra and couplings come from the geometry of the extra dimensions. ◮ All scales, matter, particle spectra and couplings come from the geometry of the extra dimensions. Joseph Conlon (Oxford University) String Phenomenology Introduction Model Building Moduli Stabilisation Flavour Problem Model Building Various approaches in string theory to realising Standard Model-like spectra: ◮ E8 E8 heterotic string with gauge bundles × ◮ Type I string with gauge bundles ◮ IIA/IIB D-brane constructions ◮ Heterotic M-Theory ◮ M-Theory on G2 manifolds Joseph Conlon (Oxford University) String Phenomenology Introduction Model Building Moduli Stabilisation Flavour Problem Heterotic String Start with an E8 vis E8 hid gauge group in ten dimensions. -
Distinguished University Professor" at the University of Amsterdam Since 2005, Where He Has Held the Chair of Mathematical Physics Since 1992
Biography Robbert Dijkgraaf Robbert Dijkgraaf (born 1960) has been "Distinguished University Professor" at the University of Amsterdam since 2005, where he has held the chair of mathematical physics since 1992. Since 2008 he is President of the Royal Netherlands Academy of Arts and Sciences (KNAW). Robbert Dijkgraaf studied physics and mathematics at Utrecht University. After an interlude studying painting at Amsterdam's Gerrit Rietveld Academy, he gained his PhD cum laude in Utrecht in 1989. His supervisor was the Nobel Prize-winner Gerard 't Hooft. Robbert Dijkgraaf subsequently held positions at Princeton University and at Princeton's Institute for Advanced Study. His current focus is on string theory, quantum gravity, and the interface between mathematics and particle physics. His research was recognized in 2003 with the award of the NWO Spinoza Prize, the highest scientific award in the Netherlands. Robbert Dijkgraaf has been a visiting professor at universities including Harvard, MIT, Berkeley, and Kyoto. He is on the editorial boards of numerous scientific periodicals, and is also the scientific adviser to institutes in Cambridge, Bonn, Stanford, Dublin, and Paris. Since 2009 he is co-chair of the InterAcademy Council, a multinational organization of science academies, together with Professor Lu Yongxiang, President of the Chinese Academy of Sciences. Many of his activities are at the interface between science and society. His column in the NRC Handelsblad newspaper is intended for a broad public and deals with science, the arts, and other matters. A collection has been published in his book Blikwisselingen (Prometheus | Bert Bakker, 2008). Robbert Dijkgraaf is dedicated to bringing about greater public awareness of science, for example through his involvement with popular TV science programmes. -
Wall-Crossing, Free Fermions and Crystal Melting
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Springer - Publisher Connector Commun. Math. Phys. 301, 517–562 (2011) Communications in Digital Object Identifier (DOI) 10.1007/s00220-010-1153-1 Mathematical Physics Wall-Crossing, Free Fermions and Crystal Melting Piotr Sułkowski1,2, 1 California Institute of Technology, Pasadena, CA 91125, USA. E-mail: [email protected] 2 Jefferson Physical Laboratory, Harvard University, Cambridge, MA 02138, USA Received: 15 December 2009 / Accepted: 10 June 2010 Published online: 26 October 2010 – © The Author(s) 2010. This article is published with open access at Springerlink.com Abstract: We describe wall-crossing for local, toric Calabi-Yaumanifolds without com- pact four-cycles, in terms of free fermions, vertex operators, and crystal melting. Firstly, to each such manifold we associate two states in the free fermion Hilbert space. The overlap of these states reproduces the BPS partition function corresponding to the non- commutative Donaldson-Thomas invariants, given by the modulus square of the topolog- ical string partition function. Secondly, we introduce the wall-crossing operators which represent crossing the walls of marginal stability associated to changes of the B-field through each two-cycle in the manifold. BPS partition functions in non-trivial chambers are given by the expectation values of these operators. Thirdly, we discuss crystal inter- pretation of such correlators for this whole class of manifolds. We describe evolution of these crystals upon a change of the moduli, and find crystal interpretation of the flop transition and the DT/PT transition. The crystals which we find generalize and unify various other Calabi-Yau crystal models which appeared in literature in recent years. -
Holography, Quantum Geometry, and Quantum
HOLOGRAPHY, QUANTUM GEOMETRY, AND QUANTUM INFORMATION THEORY P. A. Zizzi Dipartimento di Astronomia dell’ Università di Padova, Vicolo dell’ Osservatorio, 5 35122 Padova, Italy e-mail: [email protected] ABSTRACT We interpret the Holographic Conjecture in terms of quantum bits (qubits). N-qubit states are associated with surfaces that are punctured in N points by spin networks’ edges labelled by the spin- 1 representation of SU (2) , which are in a superposed quantum state of spin "up" and spin 2 "down". The formalism is applied in particular to de Sitter horizons, and leads to a picture of the early inflationary universe in terms of quantum computation. A discrete micro-causality emerges, where the time parameter is being defined by the discrete increase of entropy. Then, the model is analysed in the framework of the theory of presheaves (varying sets on a causal set) and we get a quantum history. A (bosonic) Fock space of the whole history is considered. The Fock space wavefunction, which resembles a Bose-Einstein condensate, undergoes decoherence at the end of inflation. This fact seems to be responsible for the rather low entropy of our universe. Contribution to the 8th UK Foundations of Physics Meeting, 13-17 September 1999, Imperial College, London, U K.. 1 1 INTRODUCTION Today, the main challenge of theoretical physics is to settle a theory of quantum gravity that will reconcile General Relativity with Quantum Mechanics. There are three main approaches to quantum gravity: the canonical approach, the histories approach, and string theory. In what follows, we will focus mainly on the canonical approach; however, we will consider also quantum histories in the context of topos theory [1-2]. -
Calabi-Yau Geometry and Higher Genus Mirror Symmetry
Calabi-Yau Geometry and Higher Genus Mirror Symmetry A dissertation presented by Si Li to The Department of Mathematics in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Mathematics Harvard University Cambridge, Massachusetts May 2011 © 2011 { Si Li All rights reserved. iii Dissertation Advisor: Professor Shing-Tung Yau Si Li Calabi-Yau Geometry and Higher Genus Mirror Symmetry Abstract We study closed string mirror symmetry on compact Calabi-Yau manifolds at higher genus. String theory predicts the existence of two sets of geometric invariants, from the A-model and the B-model on Calabi-Yau manifolds, each indexed by a non-negative inte- ger called genus. The A-model has been mathematically established at all genera by the Gromov-Witten theory, but little is known in mathematics for B-model beyond genus zero. We develop a mathematical theory of higher genus B-model from perturbative quantiza- tion techniques of gauge theory. The relevant gauge theory is the Kodaira-Spencer gauge theory, which is originally discovered by Bershadsky-Cecotti-Ooguri-Vafa as the closed string field theory of B-twisted topological string on Calabi-Yau three-folds. We generalize this to Calabi-Yau manifolds of arbitrary dimensions including also gravitational descen- dants, which we call BCOV theory. We give the geometric description of the perturbative quantization of BCOV theory in terms of deformation-obstruction theory. The vanishing of the relevant obstruction classes will enable us to construct the higher genus B-model. We carry out this construction on the elliptic curve and establish the corresponding higher genus B-model. -
Is String Theory Holographic? 1 Introduction
Holography and large-N Dualities Is String Theory Holographic? Lukas Hahn 1 Introduction1 2 Classical Strings and Black Holes2 3 The Strominger-Vafa Construction3 3.1 AdS/CFT for the D1/D5 System......................3 3.2 The Instanton Moduli Space.........................6 3.3 The Elliptic Genus.............................. 10 1 Introduction The holographic principle [1] is based on the idea that there is a limit on information content of spacetime regions. For a given volume V bounded by an area A, the state of maximal entropy corresponds to the largest black hole that can fit inside V . This entropy bound is specified by the Bekenstein-Hawking entropy A S ≤ S = (1.1) BH 4G and the goings-on in the relevant spacetime region are encoded on "holographic screens". The aim of these notes is to discuss one of the many aspects of the question in the title, namely: "Is this feature of the holographic principle realized in string theory (and if so, how)?". In order to adress this question we start with an heuristic account of how string like objects are related to black holes and how to compare their entropies. This second section is exclusively based on [2] and will lead to a key insight, the need to consider BPS states, which allows for a more precise treatment. The most fully understood example is 1 a bound state of D-branes that appeared in the original article on the topic [3]. The third section is an attempt to review this construction from a point of view that highlights the role of AdS/CFT [4,5]. -
Charged and Electromagnetic Fields from Relativistic Quantum Geometry
Article Charged and Electromagnetic Fields from Relativistic Quantum Geometry Marcos R. A. Arcodía 2 and Mauricio Bellini 1,2,* 1 Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, C.P. 7600 Mar del Plata, Argentina 2 Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C.P. 7600 Mar del Plata, Argentina; [email protected] * Correspondence: [email protected] Academic Editors: Lorenzo Iorio and Elias C. Vagenas Received: 3 May 2016; Accepted: 7 June 2016; Published: 21 June 2016 Abstract: In the recently introduced Relativistic Quantum Geometry (RQG) formalism, the possibility was explored that the variation of the tensor metric can be done in a Weylian integrable manifold using a geometric displacement, from a Riemannian to a Weylian integrable manifold, described by the dynamics of an auxiliary geometrical scalar field q, in order that the Einstein tensor (and the Einstein equations) can be represented on a Weyl-like manifold. In this framework we study jointly the dynamics of electromagnetic fields produced by quantum complex vector fields, which describes charges without charges. We demonstrate that complex fields act as a source of tetra-vector fields which describe an extended Maxwell dynamics. Keywords: Relativistic Quantum Geometry; Quantum Complex Fields 1. Introduction The consequences of non-trivial topology for the laws of physics has been a topic of perennial interest for theoretical physicists [1], with applications to non-trivial spatial topologies [2] like Einstein-Rosen bridges, wormholes, non-orientable spacetimes, and quantum-mechanical entanglements. -
String Phenomenology 1 Minimal Supersymmetric Standard Model
Swedish String/Supergravity Course 2008 String Phenomenology Marcus Berg 1 Minimal Supersymmetric Standard Model A good reference is Martin [2], a review that was first posted on hep-ph in 1997 but which has been updated three times, most recently in 2006. The MSSM consists of a number of chiral and vector supermultiplets, one for each existing quark or 1 lepton or gauge boson Aµ in the Standard Model (SM): spin: 0 1/2 1 N = 1 chiral supermultiplet φ N = 1 vector supermultiplet λ Aµ The new fields, the superpartners of and Aµ, are denoted by tildes and called "s-" for the new scalars, ~, and "-ino" for the new fermions, A~: 0 1/2 1 squarks, sleptons −! ~ − quarks, leptons gauginos−! A~ Aµ − gauge bosons This is just the generic notation; usually one is more specific. So for example, one N = 1 chiral mul- tiplet has the t quark as the fermionic field, and the scalar superpartner is the "stop", t~. We impose that the superpartner masses are around the TeV scale, or even a little lower. The scale of superpartner masses is not \derived" in any real sense2 in the MSSM, but from the point of view of particle phenomenology, an MSSM-like theory with only very heavy superpartners would be indistinguishable from the nonsuper- symmetric standard model at any experiments done in the foreseeable future, so why bother? In fact, even string theorists should have some favored scenario what will happen at near-future experiments and observations, so let's try to understand where people who do experiments for a living have put their money. -
The Mathematics of Fivebranes 3 Translates in a Deep Quantum Symmetry (S-Duality) of the 4-Dimensional Yang- Mills Theory
Doc. Math.J. DMV 1 Ì ÅØÑ Ó ÚÖÒ× Robbert Dijkgraaf Abstract. Fivebranes are non-perturbative objects in string theory that general- ize two-dimensional conformal field theory and relate such diverse sub- jects as moduli spaces of vector bundles on surfaces, automorphic forms, elliptic genera, the geometry of Calabi-Yau threefolds, and generalized Kac-Moody algebras. 1991 Mathematics Subject Classification: 81T30 Keywords and Phrases: quantum field theory, elliptic genera, automor- phic forms 1 Introduction This joint session of the sections Mathematical Physics and Algebraic Geometry celebrates a historic period of more than two decades of remarkably fruitful inter- actions between physics and mathematics. The ‘unreasonable effectiveness,’ depth and universality of quantum field theory ideas in mathematics continue to amaze, with applications not only to algebraic geometry, but also to topology, global anal- ysis, representation theory, and many more fields. The impact of string theory has been particularly striking, leading to such wonderful developments as mirror sym- arXiv:hep-th/9810157v1 21 Oct 1998 metry, quantum cohomology, Gromov-Witten theory, invariants of three-manifolds and knots, all of which were discussed at length at previous Congresses. Many of these developments find their origin in two-dimensional conformal field theory (CFT) or, in physical terms, in the first-quantized, perturbative for- mulation of string theory. This is essentially the study of sigma models or maps of Riemann surfaces Σ into a space-time manifold X. Through the path-integral over all such maps a CFT determines a partition function Zg on the moduli space Mg of genus g Riemann surfaces. String amplitudes are functions Z(λ), with λ the string coupling constant, that have asymptotic series of the form 2g−2 Z(λ) ∼ λ Zg.