Assoc. Prof. John V. Corbett


John V. Corbett, BSc PhD Adelaide Univ. john.corbett@mq.edu.au is an Associate Professor of Mathematical Physics and a Senior Research Fellow in the Department of Mathematics at Macquarie University-Sydney, Australia.  Areas of Research: Mathematical aspects of quantum theory including quantum entanglement and intuisionist logic. Group representations in quantum scattering theory, theory of measurement. Dynamical systems associated with quadratic systems.

Visit the school's website: http://www.science.mq.edu.au/

Mathematical Physics Research:

Physics is one of the great traditional sources of mathematical problems and these take many forms.  Some of the topics of mathematical physics in which Prof. John Corbett has contributed are as follows:

If we project N particles at each other and the number of particles Is conserved, it is physically obvious that any clustering of the particles which is possible under conservation of energy will occur with positive probability.  However, the proof of this within the usual mathematical formulation of quantum mechanics has been very difficult to obtain for an acceptable class of interactions.  John Corbett has shown that this problem is equivalent to an existence problem for certain holomorphic representations of the group SL_2(R) on the subspace of the continuous spectrum of the total Hamiltonian.  This unifies earlier work on this problem.

There is still considerable debate about the correct philosophical interpretation of quantum mechanics, despite its successful applications in physics.  In this debate the status of the measurement problem is a central issue.  It seems that what is required is a mathematical framework that embraces the standard formulation of quantum and classical mechanics, at least as limiting cases.  Prof. John Corbett and Dr. Murray Adelman have analysed some simple physical systems with this end in mind.  The idea is to construct a topos for quantum systems which can be used to measure the extent to which a physical quantity takes on various values.  This gives a useful mathematical description of a test of non-locality and non-causality in quantum mechanics proposed recently by Dr. Dipankar Home dhom@boseinst.ernet.in (a frequent visitor to Macquarie Univ. from the Bose Institute in Calcutta).  The inspiration for this new topos for quantum systems is based on an Intuitionistic logic which traces its geneology to Heyting algebras.

Recently, in collaboration with Thomas Durt, research has continued on intuitionistic logic and on the mathematical theory of what Prof. Corbett refers to as quantum real numbers (qr-numbers) in a quantum space with its own metric and topology, which is different from classical space. Quoting from his recent presentation, a preprint of which is in the publication list below, "The quantum real number (qr-number) interpretation of quantum mechanics is based on the claim that the ontological properties of microscopic entities differ from those of classical objects in that their attributes, which are represented by operators, always have values not as standard real numbers but as topos real numbers called qr-numbers. In place of the standard quantum states it uses conditions that are open subsets of quantum states [Heyting algebra tie in]. The qr-numbers, having extents as well as values, behave like functions whose domains are the extents."


Publications:

John V. Corbett, "Entanglement and the quantum spatial continuum," at "75 Years of Quantum Entanglement: Foundations and Information Theoretic Applications: S.N. Bose National Centre for Basic Sciences Silver Jubilee Symposium," 6-10 Jan. 2011, Kolkata, India, AIP Conf. Proc. 1384, pp. 34-41 (2011).

John Corbett, "Quantum particles are localized in quantum space." Preprint of presentation given at 16th UK and European Meeting on the Foundations of Physics (Aberdeen, 5-7 July 2010).

pdf copy of above presentation: Corbett_Localization_in_Quantum_Mechanics.pdf 206.8 kB, pages 1-9.

J.V. Corbett and T. Durt, "Spatial localization in quantum theory based on qr-numbers," Foundations of Physics, 40, 607-628 (2010).

J.V. Corbett and T. Durt, "An Intuitionistic Model of Single Electron Interference," Studia Logica - An International Journal for Symbolic Logic, 95, no.1, 81-100 (2010).

J.V. Corbett and T. Durt, "Collimation processes in quantum mechanics interpreted in quantum real numbers," Studies in History and Philosophy of Modern Physics, 40, pp. 68-83 (2009).

J.V. Corbett, "The mathematical structure of quantum real numbers," arXiv:math-ph/0905.0944, 7 May (2009).

J.V. Corbett and D. Home, "Bell's Inequality, Quantum Measurement and Einstein Realism: A Unified Perspective," arXiv:quant-ph/0802.2443, 18 Feb (2008).

J.V. Corbett, "The Pauli Problem, state reconstruction and quantum real numbers," Reports on Mathematical Physics, 57, 53-68 (2006).

J. Corbett and T. Durt, "Quantum mechanics as a space-time theory," arXiv:quant-ph/0512220, 23 Dec (2005).

Samuel Colin, John Corbett, Thomas Durt, and David Gross, "About SIC POVMs amd discrete Wigner distributions," Journal of Optics B-Quantum and Semiclassical Optics, 7, no.12, S778-S785 (2005).

J.V. Corbett and D. Home, "Information transfer and non-locality for a tripartite entanglement using dynamics." Phys. Lett. A 333, no.5, 382-388 (2004).

J. Corbett and T. Durt, "Quantum mechanics interpreted in Quantum Real Numbers," arXiv:quant-ph/0211180, 27 Nov (2002).

John V. Corbett and Dipankar Home, "Ipso-information-transfer," arXiv:quant-ph/0103146, 27 Mar (2001).

John V. Corbett and Dipankar Home, "Quantum effects involving interplay between unitary dynamics and kinematic entanglement." Phys. Rev. A 62, 062103 (2000).

M. Adelman and J.V. Corbett, "A Sheaf Model for Intuitionistic Quantum Mechanics." Applied Categorical Structures 3 (1), 79-104 (1995).

M. Adelman and J.V. Corbett, "Quantum Numbers Viewed Intuitionistically." in Confronting the Infintite, edited by Alan Carey, Wm. J. Ellis, and Paul A. Pearce, World Scientific Press (1995).

Murray Adelman and John V. Corbett, "A sheaf model for Intuitionistic quantum mechanics." ARC report, p. 1 (1993).

Murray Adelman, John V. Corbett, and C. A. Hurst, "The geometry of state space." Found. Phys. 23 (2), 211-223 (1993).

Murray Adelman and John V. Corbett, "Intuitionistic logic and Bell's inequalities." p. 45 (1991).

J. V. C. Corbett and C. A. Hurst, "What is needed to determine a state?" Asia-Pacific Physics News, 4 (1990).

John V. Corbett, "An Intuitionistic logic for quantum mechanics." in Proc., International Conf. "In Search of Quantum Reality" (New Delhi, India, Jan. 1990).

John V. Corbett, "On the state space structure of ideal incomplete measurements." (1989).

J. V. Corbett, "Quantum mechanical measurement of non-orthogonal states and a test of nonlocality." Phys. Lett. A 130, 419-25 (1988).

J. V. Corbett, "Scattering theory for the dilation group. I. Simple quantum mechanical scattering." J. Math. Phys. 24, 1797-805 (1983).

J.V. Corbett and C.A. Hurst, "Are wave functions uniquely determined by their position and momentum distributions?," Journal of the Australian Mathematical Society Series B-Applied Mathematics, vol.20, pt.2, pp. 182-201, Dec. 1977.

J.V. Corbett, "Unbound motion and scattering," Nuovo Cimento della Societa Italiana di Fisica B-General Physics Relativity Astronomy & Mathematical Physics Methods, vol.25B, ser.2, no.1, pp. 103-124, 11 Jan. 1975.

J.V. Corbett, "Particles and simple scattering theory," J. Math.Phys. 16, no.2, pp. 271-274, (1975).

J.V. Corbett, "Galilean symmetry, measurement, and scattering as an isomorphism between two subalgebras of observables," Phys. Rev. D 1, no.12, pp. 3331-3344 (1970).

J.V. Corbett, "Convergence of the Born series," J.Math.Phys. 9, no.6, pp. 891-898 (1968).


Supervised PhD Theses:

Dr. Dale Alan Woodside dale.woodside@mq.edu.au was awarded his PhD in 1999 for a thesis entitled "Investigation of the Uniqueness Properties of Classical Four-Vector Fields in Euclidean and Minkowski Spaces", (1998).  A copy of this thesis can be obtained through Macquarie Univ. Library by following the link from Dale's web site at URL: http://www.physics.mq.edu.au/~dalew/  In his thesis Dale Woodside develops Euclidean and Minkowski four-space extensions of Helmholtz's uniqueness theorem for three-vector fields. He then goes on to develop a new class of four-vector fields which rely on a new gauge which he calls the relativistic longitudinal gauge, where the four-curl (the Maxwell field tensor itself) is set to zero.  An article, which is based on his thesis, has been published in the Journal of Mathematical Physics.  The reference is: D. A. Woodside, "Uniqueness theorems for classical four-vector fields in Euclidean and Minkowski spaces." J. Math. Phys. 40, 4911 (1999). A second article, which completes the essential material from his thesis, has also been published in J. Math. Phys. The reference is: D. A. Woodside, "Classical four-vector fields in the relativistic longitudinal gauge." J. Math. Phys. 41, 4622 (2000). Preprints of these articles and others are available for examination (in *.ps and *.pdf format) from his web site.

Dr. David L. Tilbrook was awarded his PhD in 1997 for a thesis entitled "The Quantisation of Fields in Flat and Curved Space-times", (1996).  In his thesis David Tilbrook investigated the Fulling generalisation of the standard canonical quantisation in Minkowski space-time after first developing the generally covariant theory.  Previous authors have concluded that the spectrum of particles associated with the Davies-Unruh effect is given by a Bose-Einstein distribution, leading to what has become known as the thermalisation theorem.  In this work it is shown that if the space-time under consideration is restricted to the right-Rindler wedge then the spectrum is not thermal.  It is demonstrated, however, that the spectrum is well approximated by a Bose-Einstein distribution in the limit of very large acceleration.  In order to be able to conclude that the Fulling quantisation leads to fundamentally different Fock spaces with physically different vacuum states it is essential that these vacuum states are not coordinate dependent, and this is demonstrated with a flat space metric approach.

Dr. Greg Taylor was awarded his PhD in 1986 for a thesis entitled "Superunification in a model resembling Kaluza-Klein".  The problem of superunification is that of finding a theory which describes the four fundamental forces of nature while respecting the laws of quantum mechanics and relativity.  Greg Taylor's model assumes a universe of dimension greater than four in which the usual four dimensional space-time is embedded.  The gravitational force is described by the geometry of four dimensional space-time and the weak, strong and electromagnetic forces are represented geometrically in the higher dimensions in the manner of the Kaluza-Klein theory of electromagnetism.  These forces leave their trace on the space-time manifold as potentials that perturb the geodesics in this space.  The model does not solve all the problems, but it does give an interesting framework.

Dr. Keiko Yasukawa obtained her PhD for a thesis entitled "Study of a Nonlinear Control Algorithm Using Dynamical Systems Theory", (1990).  In her thesis Keiko Yasukawa developed a new control algorithm for nonlinear input-output systems which generalizes a linear algorithm known as model-algorithmic control (MAC) by incorporating some of the ideas from her previous study of Volterra and Wiener functional expansions.  In studying the stability properties of the equations arising in the new algorithm, it was found that these equations took a form which necessitated the development of a mathematical framework within which the stability analysis could be achieved.  Application and generalization of results from discrete dynamical systems theory proved to provide a suitable framework.


Last Modified: November 29, 2012 by:

Dale Alan Woodside, PhD ( dale.woodside@mq.edu.au)