211 results found
Borsten L, Duff MJ, Marrani A, 2019, Twin conformal field theories, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479
Duff MJ, 2018, Thirty years of Erice on the brane
After initially meeting with fierce resistance, "branes", p-dimensionalextended objects which go beyond particles (p=0) and strings (p=1), now occupycentre stage in theoretical physics as microscopic components of M-theory, asthe seeds of the AdS/CFT correspondence, as a branch of particle phenomenology,as the higher-dimensional progenitors of black holes and, via the"brane-world", as entire universes in their own right. Notwithstanding thisearly opposition, Nino Zichichi invited me to to talk about supermembranes andeleven dimensions at the 1987 School on Subnuclear Physics and has continued tokeep Erice on the brane ever since. Here I provide a distillation of my Ericebrane lectures and some personal recollections.
The Becchi-Rouet-Stora-Tyutin (BRST) transformations and equations of motion of a gravity–two-form–dilaton system are derived from the product of two Yang-Mills theories in a BRST covariant form, to linear approximation. The inclusion of ghost fields facilitates the separation of the graviton and dilaton. The gravitational gauge fixing term is uniquely determined by those of the Yang-Mills factors which can be freely chosen. Moreover, the resulting gravity–two-form–dilaton Lagrangian is anti-BRST invariant and the BRST and anti-BRST charges anticommute as a direct consequence of the formalism.
Using simple symmetry arguments we classify the ungauged D =4, N = 2, supergravity theories, coupled to both vector and hyper multiplets through homogeneous scalar manifolds, that can be built as the product of N = 2 andN = 0 matter-coupled Yang–Mills gauge theories. This includes all such supergravities with two isolated exceptions: pure supergravity and the T3 model.
Anastasiou A, Borsten L, Duff MJ, et al., 2017, Twin supergravities from Yang-Mills theory squared, PHYSICAL REVIEW D, Vol: 96, ISSN: 2470-0010
We consider “twin supergravities”—pairs of supergravities with N+ and N− supersymmetries, N+>N−, with identical bosonic sectors—in the context of tensoring super Yang-Mills multiplets. It is demonstrated that the pairs of twin supergravity theories are related through their left and right super Yang-Mills factors. This procedure generates new theories from old ones. In particular, the matter coupled N− twins in D=3, 5, 6 and the N−=1 twins in D=4 have not, as far as we are aware, been obtained previously using the double-copy construction, adding to the growing list of double-copy constructible theories. The use of fundamental matter multiplets in the double-copy construction leads us to introduce a bifundamental scalar that couples to the well-known biadjoint scalar field. It is also shown that certain matter coupled supergravities admit more than one factorization into left and right super Yang-Mills-matter theories.
Duff MJ, 2017, Abdus Salam at Imperial College, INTERNATIONAL JOURNAL OF MODERN PHYSICS A, Vol: 32, ISSN: 0217-751X
Duff MJ, Ferrara S, Marrani A, 2017, D=3 unification of curious supergravities, Journal of High Energy Physics, Vol: 2017, ISSN: 1029-8479
We consider the dimensional reduction to D = 3 of four maximal-rank super-gravities which preserve minimal supersymmetry in D = 11, 7, 5 and 4. Such “curious” theories were investigated some time ago, and the four-dimensional one corresponds to an N=1 supergravity with 7 chiral multiplets spanning the seven-disk manifold. Recently, this latter theory provided cosmological models for α-attractors, which are based on the disk geometry with possible restrictions on the parameter α. A unified picture emerges in D = 3, where the Ehlers group of General Relativity merges with the S-, T- and U-dualities of the D = 4 parent theories.
Borsten L, Duff MJ, 2017, Majorana Fermions in Particle Physics, Solid State and Quantum Information, 53rd Course of the International-School-of-Subnuclear-Physics (ISSP), Publisher: WORLD SCIENTIFIC PUBL CO PTE LTD
Borsten L, Duff MJ, 2017, Gravity as the square of Yang-Mills?, 53rd Course of the International-School-of-Subnuclear-Physics (ISSP), Publisher: WORLD SCIENTIFIC PUBL CO PTE LTD
Borsten L, Duff MJ, 2015, Gravity as the square of Yang-Mills?, PHYSICA SCRIPTA, Vol: 90, ISSN: 0031-8949
Borsten L, Bradler K, Duff MJ, 2015, The structure of superqubit states, Rivista del Nuovo Cimento, Vol: 38, Pages: 371-386, ISSN: 0393-697X
Duff MJ, 2015, M-history without the M, Contemporary Physics, Vol: 57, Pages: 83-85, ISSN: 0010-7514
Duff MJ, 2015, How fundamental are fundamental constants?, Contemporary Physics, Vol: 56, Pages: 35-47, ISSN: 0010-7514
I argue that the laws of physics should be independent of one’s choice of units or measuring apparatus. This is the case if they are framed in terms of dimensionless numbers such as the fine structure constant, α. For example, the standard model of particle physics has 19 such dimensionless parameters whose values all observers can agree on, irrespective of what clock, rulers or scales… they use to measure them. Dimensional constants, on the other hand, such as ħ, c, G, e and k …, are merely human constructs whose number and values differ from one choice of units to the next. In this sense, only dimensionless constants are ‘fundamental’. Similarly, the possible time variation of dimensionless fundamental ‘constants’ of nature is operationally well defined and a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants such as c or G on which a good many (in my opinion, confusing) papers have been written, is a unit-dependent phenomenon on which different observers might disagree depending on their apparatus. All these confusions disappear if one asks only unit-independent questions. We provide a selection of opposing opinions in the literature and respond accordingly.
Borsten L, Bradler K, Duff MJ, 2014, Tsirelson's bound and supersymmetric entangled states, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 470, ISSN: 1364-5021
Borsten L, Duff MJ, Ferrara S, et al., 2014, Explicit Orbit Classification of Reducible Jordan Algebras and Freudenthal Triple Systems, COMMUNICATIONS IN MATHEMATICAL PHYSICS, Vol: 325, Pages: 17-39, ISSN: 0010-3616
Duff MJ, 2013, Black holes and qubits, Proceedings of the International School of Subnuclear Physics, Publisher: World Scientific Publ Co, Pages: 57-66
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.
Duff MJ, 2013, String and M-Theory: Answering the Critics (vol 43, pg 182, 2013), FOUNDATIONS OF PHYSICS, Vol: 43, Pages: 284-284, ISSN: 0015-9018
Duff MJ, 2013, String and M-Theory: Answering the critics, Foundations of Physics, Vol: 43, Pages: 182-200, ISSN: 0015-9018
Using as a springboard a three-way debate between theoretical physicist Lee Smolin, philosopher of science Nancy Cartwright and myself, I address in layman’s terms the issues of why we need a unified theory of the fundamental interactions and why, in my opinion, string and M-theory currently offer the best hope. The focus will be on responding more generally to the various criticisms. I also describe the diverse application of string/M-theory techniques to other branches of physics and mathematics which render the whole enterprise worthwhile whether or not “a theory of everything” is forthcoming.
Duff MJ, 2013, The black hole/qubit correspondence, 6th International Symposium on Quantum Theory and Symmetries (QTS), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
Borsten L, Duff MJ, Levay P, 2012, The black-hole/qubit correspondence: an up-to-date review, CLASSICAL AND QUANTUM GRAVITY, Vol: 29, ISSN: 0264-9381
Borsten L, Duff MJ, Rubens W, 2012, Black holes and qubits, Summer School on Decoherence, Entanglement and Entropy / Workshop on Matrix Product State Formulation and Density Matrix Renormalization Group Simulations, Publisher: World Scientific Publ Co, Pages: 3-107, ISSN: 1793-7299
These notes have been compiled to accompany a series of four lectures given at the Kinki University Quantum Computing Series Summer School on Decoherence, Entanglement and Entropy, August 2009 at the Oxford Kobe Institute (Kobe, Japan).Each of the four lectures focuses on a particular topic falling under the broad umbrella of the "black-hole/qubit correspondence". Lecture I introduces the first instance of the black-hole/qubit correspondence, the relationship between the entanglement of three qubits and the entropy of STU black holes. Lecture II develops this correspondence to the case of black holes and the tripartite entanglement of seven qubits. Lecture III examines the use of Jordan algebras and the Freudenthal triple system, which capture the U-duality symmetries of these black hole systems, in entanglement classification. Lecture IV introduces the superqubit, a natural candidate to represent supersymmetric quantum information.These lectures draw on work done with D. Dahanayake, H. Ebrahim, S. Ferrara and A. Marrani whose efforts are most gratefully acknowledged.
Duff MJ, 2011, M-theory on manifolds of G2 holonomy: the first twenty years
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