On the highlights side, ASGRG has been granted cognate society status with the Australian Institute of Physics. This has the immediate benefit for ASGRG members in providing us with a 10% reduction on the AIP annual subscription fee. If you are not already a member of the AIP, now would be a good time to support physics in Australia. As a cognate society we are required to run a mini workshop at AIP Congresses (more on this below) and be represented at the AIP Council meeting each February.
In regard to societies, we should consider whether or not to join FASTS. David Wiltshire, Susan Scott and I attended the recent Science meets Parliament day in Canberra. Though David and Susan both represented the AIP, we did our bit to promote the ASGRG. Membership of FASTS would allow us to be fully represented at such events and have formal input on matters effecting science in Australia.
Of great importance to the gravitational wave detection community is the awarding of the Fourth Amaldi Conference on Gravitational waves to Perth. This major international meeting will be held in July 2001, immediately before the South African GR conference. Hopefully this will encourage visitors from the northern hemisphere to include both meetings in their itineraries.
Given that Amaldi will be held in Perth, we are proposing to postpone the next meeting of our Society, which was to be held in Perth in December 2000, until July 2001 and run it just before the Amaldi meeting but with a one or two day overlap at the end on gravitational wave research. This will assist us in financing ASGRG3 by sharing some costs for visitors and facilities with the Amaldi and will be further incentive for people to have a southern relativity experience. David Wiltshire will expand on this below and explain how we will go about getting your approval for this change.
Unfortunately, not all has been positive. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) submitted an application for a Special Research Centre to undertake R&D toward gravitational wave detection. Though being highly praised for the research training environment it would provide, the ARC committee had its doubts about whether the innovative technology could be achieved. Obviously there is much work we have to do in educating the broader physics community on what we have already achieved and are currently doing. One event that will aid us in doing this is the opening, in March 2000, of the new gravitational wave physics laboratory in Gingin, WA, a chosen site for a future long baseline detector. Prof Barish from LIGO will attend as part of an Australian speaking tour so look out for him in your state.
On a further gloomy note, I note that Dr. Peter Szekeres has decided to take early retirement. Peter was the founding president of the ASGRG. His contributions to general relativity and to student education are world renown. We will celebrate Peter's achievement during the GR workshop to be held in association with the AIP Congress.
Well, from now on we hope to circulate this electronic newsletter on a quarterly basis. The editor will ask for articles a week before publication so please submit any news, list of abstracts, jobs available, or upcoming events that you think the GRG community should know about. Until April
- David McClelland
At the University of Adelaide we are also facing down-sizing. A number of early retirements were sought in the Dept of Physics and Mathematical Physics due to the Department facing a budget deficit of order 25%. Unfortunately this is a familiar story around Australia. (People at Monash have been through all of this not so long ago. At U Queensland they are going through another round, with Mathematics and Physics to be amalgamated.) Anyway, the upshot is that Peter Szekeres is amongst those who have put their hands up for early retirement. He is the last tenured staff member in the Mathematical Physics group. The future of the group is in jeopardy since it is crumbling as the contracts of the younger members expire. What exactly is happening is still not clear at this point, as the Department's problems have been side-lined for the present by debate about a restructuring of the whole Faculty of Science, which you may have seen reported in the press.
On a more positive note, we have gained cognate status with the AIP, and will hold a workshop to celebrate Peter Szekeres' contributions to relativity in Adelaide in December, in conjunction with the AIP2000 Congress (further details below). Peter - who turns 60 in August, 2000 - is well-known for his many significant contributions to many areas of relativity, including singularity theory and the colliding gravitational wave solutions and inhomogenous cosmological models which bear his name. We are aiming to produce a Festschrift in conjunction with the Workshop.
At a committee meeting in November, we decided to try to make the newsletters much more frequent (which will mean briefer). We are aiming to make them quarterly, so the next one will be just before Easter. Please send your contributions, abstracts of new papers etc to asgrg@physics.adelaide.edu.au by March 31, 2000.
- David Wiltshire
- Request to membership for approval of dates -
The logistics of running the two meetings has yet to be decided. One suggestion is to run them with an overlap of a couple of days. Another suggestion is to run the conferences entirely in parallel, with one shared plenary talk each morning. The exact logistics will be worked out in discussion with the organisers of the Amaldi Conference once we obtain our members' approval for the July, 2001 date.
There were other reasons making a 2000 conference date undesirable - in July 2000 the Marcel Grossman meeting is being held in Rome; while the other logical choice of the mid-semester break in September clashes with the Sydney Olympics, at which time travel for those going through Sydney will be tight. In any case, we will have one 2000 event with the workshop in Adelaide (below).
Since a July 2001 date is 6 months beyond the natural "term" outlined in our Constitution, we are required [clause 15(i)] to get a simple majority of members to consent to this. Please return the remote ballot email to allow us to go ahead with this.
It is requested that ballots are returned by February 28, 2000.
----------------------------------------------------------------------------- \\ Paper: gr-qc/9807001 From: Sam Drake <sdrake@physics.adelaide.edu.au> Date: Wed, 1 Jul 1998 07:44:03 GMT (9kb) Title: An explanation of the Newman-Janis Algorithm Authors: S. P. Drake P. Szekeres Comments: 14 pages, no figures. \\ After the original discovery of the Kerr metric, Newman and Janis showed that this solution could be ``derived'' by making an elementary complex transformation to the Schwarzschild solution. The same method was then used to obtain a new stationary axisymmetric solution to Einstein's field equations now known as the Kerr-Newman metric, representing a rotating massive charged black hole. However no clear reason has ever been given as to why the Newman-Janis algorithm works, many physicist considering it to be an ad hoc procedure or ``fluke'' and not worthy of further investigation. Contrary to this belief this paper shows why the Newman-Janis algorithm is successful in obtaining the Kerr-Newman metric by removing some of the ambiguities present in the original derivation. Finally we show that the only perfect fluid generated by the Newman-Janis algorithm is the (vacuum) Kerr metric and that the only Petrov typed D solution to the Einstein-Maxwell equations is the Kerr-Newman metric. \\ ( http://xxx.lanl.gov/abs/gr-qc/9807001 , 9kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9807028 From: Tevian Dray <tevian@math.orst.edu> Date: Tue, 14 Jul 1998 18:08:34 GMT (11kb) Title: A New Look at the Ashtekar-Magnon Energy Condition Authors: Jim Fischer, Tevian Dray Comments: REVTeX, 10 pages Journal-ref: Gen.Rel.Grav. 31 (1999) 511-526 \\ In 1975, Ashtekar and Magnon showed that an energy condition selects a unique quantization procedure for certain observers in general, curved spacetimes. We generalize this result in two important ways, by eliminating the need to assume a particular form for the (quantum) Hamiltonian, and by considering the surprisingly nontrivial extension to nonminimal coupling \\ ( http://xxx.lanl.gov/abs/gr-qc/9807028 , 11kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9807075 From: David Wiltshire <dlw@physics.adelaide.edu.au> Date: Tue, 28 Jul 1998 17:22:29 GMT (16kb) Date (revised v2): Thu, 24 Dec 1998 06:43:44 GMT (22kb) Date (revised v3): Mon, 1 Mar 1999 02:21:37 GMT (22kb) Title: Operator ordering and consistency of the wavefunction of the Universe Authors: N. Kontoleon and D.L. Wiltshire Comments: 9 pages, epsf, revTeX-3.1, 1 figure. In revised version (v2) a new section etc with additional arguments increases the length of paper by 3 pages of Physical Review; several references added. v3: small typos fixed Report-no: ADP-98-43/M71 Journal-ref: Phys. Rev. D59 (1999) 063513 \\ We demonstrate in the context of the minisuperspace model consisting of a closed Friedmann-Robertson-Walker universe coupled to a scalar field that Vilenkin's tunnelling wavefunction can only be consistently defined for particular choices of operator ordering in the Wheeler-DeWitt equation. The requirement of regularity of the wavefunction has the particular consequence that the probability amplitude, which has been used previously in the literature in discussions of issues such as the prediction of inflation, is likewise ill-defined for certain choices of operator ordering with Vilenkin's boundary condition. By contrast, the Hartle-Hawking no-boundary wavefunction can be consistently defined within these models, independently of operator ordering. The significance of this result is discussed within the context of the debate about the predictions of semiclassical quantum cosmology. In particular, it is argued that inflation cannot be confidently regarded as a "prediction" of the tunnelling wavefunction, for reasons similar to those previously invoked in the case of the no-boundary wavefunction. A synthesis of the no-boundary and tunnelling approaches is argued for. \\ ( http://xxx.lanl.gov/abs/gr-qc/9807075 , 22kb) ----------------------------------------------------------------------------- \\ Paper: astro-ph/9807311 From: Neil John Cornish <N.J.Cornish@damtp.cam.ac.uk> Date: Thu, 30 Jul 1998 00:00:39 GMT (315kb) Date (revised v2): Wed, 5 Aug 1998 14:04:14 GMT (315kb) Title: Measuring the shape of the Universe Authors: Neil J. Cornish (DAMTP, Cambridge), Jeffrey R. Weeks (Canton) Comments: 18 pages, 8 figures, AMS LaTeX, Accepted for publication as a Feature Article in the Notices of the American Mathematical Society Report-no: Canton-98-2 \\ Since the dawn of civilization, humanity has grappled with the big questions of existence and creation. Modern cosmology seeks to answer some of these questions using a combination of mathematics and measurement. The questions people hope to answer include ``how did the universe begin?''; ``how will the universe end?''; ``is space finite or infinite?''. After a century of remarkable progress, cosmologists may be on the verge of answering at least one of these questions -- is space finite? Using some simple geometry and a NASA satellite set for launch in the year 2000, the authors and their colleagues hope to measure the size and shape of space. This review article explains the mathematics behind the measurement, and the cosmology behind the observations. \\ ( http://xxx.lanl.gov/abs/astro-ph/9807311 , 315kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9809082 From: David Hartley <dhartley@physics.adelaide.edu.au> Date: Wed, 30 Sep 1998 02:28:24 GMT (7kb) Title: On Waylen's regular axisymmetric similarity solutions Authors: Edward D. Fackerell, David Hartley Comments: 8 pages, LaTeX2e Report-no: ADP-98-38/M69 \\ We review the similarity solutions proposed by Waylen for a regular time-dependent axisymmetric vacuum space-time, and show that the key equation introduced to solve the invariant surface conditions is related by a Baecklund transform to a restriction on the similarity variables. We further show that the vacuum space-times produced via this path automatically possess a (possibly homothetic) Killing vector, which may be time-like. \\ ( http://xxx.lanl.gov/abs/gr-qc/9809082 , 7kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9810031 From: Adrian P. Gentle <adrian@regge.lanl.gov> Date: Thu, 8 Oct 1998 20:13:29 GMT (23kb) Title: Geodesic Deviation in Regge Calculus Authors: Sukanya Chakrabarti, Adrian P. Gentle, Arkady Kheyfets, Warner A. Miller Comments: 9 pages. Latex 2e with 5 EPS figures. Submitted to CQG Report-no: LAUR-98-4237 Journal-ref: Class.Quant.Grav. 16 (1999) 2381-2391 \\ Geodesic deviation is the most basic manifestation of the influence of gravitational fields on matter. We investigate geodesic deviation within the framework of Regge calculus, and compare the results with the continuous formulation of general relativity on two different levels. We show that the continuum and simplicial descriptions coincide when the cumulative effect of the Regge contributions over an infinitesimal element of area is considered. This comparison provides a quantitative relation between the curvature of the continuous description and the deficit angles of Regge calculus. The results presented might also be of help in developing generic ways of including matter terms in the Regge equations. \\ ( http://xxx.lanl.gov/abs/gr-qc/981031, 23kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9811063 From: IBRAHIM ARBAB ARBAB <arbab@ictp.trieste.it> Date: Thu, 19 Nov 1998 10:00:38 GMT (4kb) Date (revised v2): Mon, 7 Dec 1998 12:26:09 GMT (4kb) Title: Causal Dissipative Cosmology With Variable G and Lambda Authors: Arbab I. Arbab, A. Beesham Comments: revised version, 6 LaTeX pages \\ A cosmological model with variable G and Lambda is considered in the framework of Israel-Stewart-Hiscock (ISH) causal theory. Power law as well as inflationary solutions are obtained. The gravitational constant is found to increase with time. \\ ( http://xxx.lanl.gov/abs/gr-qc/9811063, 4kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9812022 From: Geoffery Ericksson <gbe105@rsphy1.anu.edu.au> Date: Mon, 7 Dec 1998 05:08:12 GMT (17kb) Title: Cosmological models with isotropic singularities Authors: Susan M. Scott, Geoffery Ericksson Comments: 10 pages, 1 figure Journal-ref: Proc. Int. Sem. Math. Cosmol., Potsdam 1998, Editors: M. Rainer, H.-J. Schmidt, WSPC, Singapore, pp123-132 \\ In 1985 Goode and Wainwright devised the concept of an isotropic singularity. Since that time, numerous authors have explored the interesting consequences, in mathematical cosmology, of assuming the existence of this type of singularity. In this paper, we collate all examples of cosmological models which are known to admit an isotropic singularity, and make a number of observations regarding their general characteristics. \\ ( http://xxx.lanl.gov/abs/gr-qc/9812022 , 17kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9812057 From: Adrian P. Gentle <adrian@regge.lanl.gov> Date: Wed, 16 Dec 1998 20:46:57 GMT (72kb) Title: Apparent horizons in simplicial Brill wave initial data Authors: Adrian P. Gentle, Daniel E. Holz, Warner A. Miller, John A. Wheeler Comments: 7 pages, 6 EPS figures, LaTeX 2e. Submitted to Class. Quant. Grav Report-no: LAUR-98-5276 Journal-ref: Class.Quant.Grav. 16 (1999) 1979-1985 \\ We construct initial data for a particular class of Brill wave metrics using Regge calculus, and compare the results to a corresponding continuum solution, finding excellent agreement. We then search for trapped surfaces in both sets of initial data, and provide an independent verification of the existence of an apparent horizon once a critical gravitational wave amplitude is passed. Our estimate of this critical value, using both the Regge and continuum solutions, supports other recent findings. \\ ( http://xxx.lanl.gov/abs/gr-qc/9812057 , 72kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9812083 From: "" <phrtc@flinders.edu.au> Date: Thu, 24 Dec 1998 01:20:09 GMT (62kb) Date (revised v2): Mon, 28 Dec 1998 06:40:30 GMT (62kb) Title: Self-Referential Noise and the Synthesis of Three-Dimensional Space Authors: Reginald T. Cahill, Christopher M. Klinger (Department of Physics, Flinders University) Comments: Figure labels corrected \\ Generalising results from Godel and Chaitin in mathematics suggests that self-referential systems contain intrinsic randomness. We argue that this is relevant to modelling the universe and show how three-dimensional space may arise from a non-geometric order-disorder model driven by self-referential noise. \\ ( http://xxx.lanl.gov/abs/gr-qc/9812083 , 62kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9901071 From: Adrian P. Gentle <adrian@regge.lanl.gov> Date: Mon, 25 Jan 1999 18:14:08 GMT (264kb) Title: Simplicial Brill wave initial data Authors: Adrian P. Gentle Comments: 17 pages, LaTeX 2e, 13 eps figures. Submitted to CQG Report-no: LAUR-99-304 Journal-ref: Class.Quant.Grav. 16 (1999) 1987-2003 \\ Regge calculus is used to construct initial data for vacuum axisymmetric Brill waves at a moment of time symmetry. We argue that only a tetrahedral lattice can successfully reproduce the continuum solution, and develop a simplicial axisymmetric lattice based on the co-ordinate structure of the continuum metric. This is used to construct initial data for Brill waves in an otherwise flat spacetime, and for the distorted black hole spacetime of Bernstein. These initial data sets are shown to be second order accurate approximations to the corresponding continuum solutions. \\ ( http://xxx.lanl.gov/abs/gr-qc/9901071 , 264kb) ----------------------------------------------------------------------------- \\ Paper: gr-qc/9904045 From: Robert Bartnik <bartnik@stan.canberra.edu.au> Date: Mon, 19 Apr 1999 10:48:30 GMT (334kb) Title: Einstein equations in the null quasi-spherical gauge III: numerical algorithms Authors: Robert A. Bartnik and Andrew H. Norton Comments: Latex, 38 pages, 29 figures (360Kb compressed) Report-no: ISE RR 99/110 \\ We describe numerical techniques used in the construction of our 4th order evolution for the full Einstein equations, and assess the accuracy of representative solutions. The code is based on a null gauge with a quasi-spherical radial coordinate, and simulates the interaction of a single black hole with gravitational radiation. Techniques used include spherical harmonic representations, convolution spline interpolation and filtering, and an RK4 "method of lines" evolution. For sample initial data of "intermediate" size (gravitational field with 19% of the black hole mass), the code is accurate to 1 part in 10^5, until null time z=55 when the coordinate condition breaks down. \\ ( http://xxx.lanl.gov/abs/gr-qc/9904045 , 334kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9903056 From: Tamath Rainsford <eguest@pilot.physics.adelaide.edu.au> Date: Mon, 15 Mar 1999 07:32:48 GMT (10kb) Title: Post-Newtonian Cosmology Authors: Tamath Rainsford, Peter Szekeres Comments: 12 pages, Latex \\ Newtonian Cosmology is commonly used in astrophysical problems, because of its obvious simplicity when compared with general relativity. However it has inherent difficulties, the most obvious of which is the non-existence of a well-posed initial value problem. In this paper we investigate how far these problems are met by using the post-Newtonian approximation in cosmology. \\ ( http://xxx.lanl.gov/abs/gr-qc/9903056 , 334kb) ------------------------------------------------------------------------------ \\ Paper: hep-th/9905025 From: Patrick Peter <patrick.peter@obspm.fr> Date: Wed, 5 May 1999 07:24:18 GMT (18kb) Title: Dynamics and integrability property of the chiral string model Authors: Brandon Carter, Patrick Peter Comments: 7 pages, 2 eps figures included, uses ReVTeX Report-no: DARC/99-09 Journal-ref: Phys.Lett. B466 (1999) 41-49 \\ The effect of fermionic string conductivity by purely right (or purely left) moving ``zero modes'' is shown to be governed by a simple Lagrangian characterising a certain ``chiral'' (null current carrying) string model whose dynamical equations of motion turn out to be explicitly integrable in a flat spacetime background. \\ ( http://xxx.lanl.gov/abs/hep-th/9905025 , 18kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9905082 From: " " <phrtc@flinders.edu.au> Date: Fri, 21 May 1999 03:58:47 GMT (18kb) Title: Self-Referential Noise as a Fundamental Aspect of Reality Authors: Reginald T. Cahill, Christopher M. Klinger (Department of Physics, Flinders University) Comments: 7 pages, Latex, 3 ps figures. Contribution to the 2nd International Conference on Unsolved Problems of Noise, Adelaide 1999 \\ Noise is often used in the study of open systems, such as in classical Brownian motion and in Quantum Dynamics, to model the influence of the environment. However generalising results from G\"{o}del and Chaitin in mathematics suggests that systems that are sufficiently rich that self-referencing is possible contain intrinsic randomness. We argue that this is relevant to modelling the universe, even though it is by definition a closed system. We show how a three-dimensional process-space may arise, as a Prigogine dissipative structure, from a non-geometric order-disorder model driven by, what is termed, self-referential noise. \\ ( http://xxx.lanl.gov/abs/gr-qc/9905082 , 18kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9905090 From: David Wiltshire <dlw@physics.adelaide.edu.au> Date: Mon, 24 May 1999 07:55:49 GMT (13kb) Title: Wave functions for arbitrary operator ordering in the de Sitter minisuperspace approximation Authors: D.L. Wiltshire Comments: 12 pages, revTeX-3.1 Report-no: ADP-99-22/M81 \\ We derive exact series solutions for the Wheeler-DeWitt equation corresponding to a spatially closed Friedmann-Robertson-Walker universe with cosmological constant for arbitrary operator ordering of the scale factor of the universe. The resulting wave functions are those relevant to the approximation which has been widely used in two-dimensional minisuperspace models with an inflationary scalar field for the purpose of predicting the period of inflation which results from competing boundary condition proposals for the wave function of the universe. The problem that Vilenkin's tunneling wave function is not normalizable for general operator orderings, is shown to persist for other values of the spatial curvature, and when additional matter degrees of freedom such as radiation are included. \\ ( http://xxx.lanl.gov/abs/gr-qc/9905090 , 13kb) ------------------------------------------------------------------------------ \\ Paper: math.DG/9906017 From: Neil Cornish <njc@astro.princeton.edu> Date: Wed, 2 Jun 1999 16:46:10 GMT (547kb) Title: On the eigenmodes of compact hyperbolic 3-manifolds Authors: Neil J. Cornish, David N. Spergel Comments: 8 pages, 10 figures. Submitted to Experimental Mathematics Subj-class: Differential Geometry MSC-class: 53C80 \\ We present a simple algorithm for finding eigenmodes of the Laplacian for arbitrary compact hyperbolic 3-manifolds. We apply our algorithm to a sample of twelve manifolds and generate a list of the lowest eigenvalues. We also display a selection of eigenmodes taken from the Weeks space. \\ ( http://xxx.lanl.gov/abs/math/9906017 , 547kb) ------------------------------------------------------------------------------ Paper: astro-ph/9906401 From: njc@astro.Princeton.EDU Date: Fri, 25 Jun 1999 04:10:55 GMT (481kb) Date (revised v2): Sat, 26 Jun 1999 20:15:09 GMT (481kb) Title: A small universe after all? Authors: Neil J. Cornish, David N. Spergel (Princeton University) Comments: 4 pages, RevTeX, 7 Figures \\ The cosmic microwave background radiation allows us to measure both the geometry and topology of the universe. It has been argued that the COBE-DMR data already rule out models that are multiply connected on scales smaller than the particle horizon. Here we show the opposite is true: compact (small) hyperbolic universes are favoured over their infinite counterparts. For a density parameter of Omega_o=0.3, the compact models are a better fit to COBE-DMR (relative likelihood ~20) and the large-scale structure data (sigma_8 increases by ~25%). \\ ( http://xxx.lanl.gov/abs/astro-ph/9906401 , 481kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9907039 From: Brandon CARTER <carter@mesiob.obspm.fr> Date: Fri, 9 Jul 1999 14:08:43 GMT (30kb) Title: Vortex Dynamics in Superfluids Authors: Brandon Carter Comments: 39 pages, Latex; contrib. to `Topological defects and non-equilibrium dynamics of phase transitions' ed Y. Bunkov, H. Godfrin, Les Houches Winter School, February 1999 \\ Superfluid condensates are known to occur in contexts ranging from laboratory liquid helium to neutron stars, and are also likely to occur in cosmological phenomena such as axion fields. In the zero temperature limit, such condensates are describable at a mesoscopic level by irrotational configurations of simple relativistic perfect fluid models. The general mechanical properties of such models are presented here in an introductory review giving special attention to the dynamics of vorticity flux 2-surfaces and the action principles governing both individual flow trajetories and the evolution of the system as a whole. Macroscopic rotation of such a condensate requires the presence of a lattice of quantised vortex defects, whose averaged tension violates perfect fluid isotropy. It is shown that for any equation of state (relating the mass density $\rho$ to the pressure $P$) the mesoscopic perfect fluid model can be extended in a uniquely simple and natural manner to a corresponding macroscopic model (in a conformally covariant category) that represents the effects of the vortex fibration anisotropy. The limiting case of an individual vortex defect is shown to be describable by a (``global'') string type model with a variable tension ${\cal T}$ (obtained as a function of the background fluid density) whose ``vorton'' (i.e. closed loop equilibrium) states are derived as an exercise. \\ ( http://xxx.lanl.gov/abs/gr-qc/9907039 , 30kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9907094 From: Tamath Rainsford <eguest@physics.adelaide.edu.au> Date: Wed, 28 Jul 1999 08:47:40 GMT (10kb) Date (revised v2): Sun, 12 Sep 1999 07:41:45 GMT (11kb) Title: Newtonian and Post-Newtonian approximations of the k = 0 Friedmann Robertson Walker Cosmology Author: Tamath Rainsford (University of Adelaide) Comments: 11 pages, Latex, corrected typos Report-no: The University of Adelaide preprint ADP-99-29/M84 \\ In a previous paper we derived a post-Newtonian approximation to cosmology which, in contrast to former Newtonian and post-Newtonian cosmological theories, has a well-posed initial value problem. In this paper, this new post-Newtonian theory is compared with the fully general relativistic theory, in the context of the k = 0 Friedmann Robertson Walker cosmologies. It is found that the post-Newtonian theory reproduces the results of its general relativistic counterpart, whilst the Newtonian theory does not. \\ ( http://xxx.lanl.gov/abs/gr-qc/9907094 , 11kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9911021 From: Simon Davis <simond@maths.usyd.edu.au> Date: Sat, 6 Nov 1999 09:26:49 GMT (10kb) Date (revised v2): Wed, 10 Nov 1999 21:31:54 GMT (10kb) Title: Higher-Derivative Quantum Cosmology Authors: Simon Davis Comments: 11 pages TeX. A term has been removed from equation (13) Report-no: Report 99-12 \\ The quantum cosmology of a higher-derivative derivative gravity theory arising from the heterotic string effective action is reviewed. A new type of Wheeler-DeWitt equation is obtained when the dilaton is coupled to the quadratic curvature terms. Techniques for solving the Wheeler-DeWitt equation with appropriate boundary conditions shall be described, and implications for semiclassical theories of inflationary cosmology will be outlined. \\ ( http://xxx.lanl.gov/abs/gr-qc/9911021 , 10kb) ------------------------------------------------------------------------------ \\ Paper: gr-qc/9911043 From: Simon Davis <simond@maths.usyd.edu.au> Date: Wed, 10 Nov 1999 23:04:20 GMT (13kb) Title: The Effect of Higher-Derivative Curvature Terms on String Quantum Cosmology Authors: Simon Davis Comments: 16 pages, TeX Report-no: Report 99-23 \\ Several new results regarding the quantum cosmology of the quadratic gravity theory derived from the heterotic string effective action are presented. After describing techniques for solving the Wheeler-De Witt equation with appropriate boundary conditions, results are compared with semi-classical theories of inflationary cosmology and implications for various different string cosmology models are outlined. \\ ( http://xxx.lanl.gov/abs/gr-qc/9911043 , 13kb) ------------------------------------------------------------------------------