Spiros Cotsakis
Professor of Mathematical Physics
and Cosmology
University
of the Aegean
“It is
legitimate for the mathematician to study all possible models, with arbitrary
topology as well as arbitrary Lorentzian metric. It is still believed by the
majority of physicists and astronomers that such a manifold does model the
cosmos, and moreover its metric satisfies the Einstein equations, eventually in
dimensions greater than four. This hypothesis opens a vast field of
investigations, where remarkable conjectures have been proposed. Many results
have been obtained, sometimes surprising, but many fundamental questions remain
open.” Yvonne Choquet-Bruhat.
“Albert Einstein, foremost twentieth century
scientist, once said: ``The most incomprehensible thing about the universe is
that it is comprehensible’’. We may complement Einstein’s remark by adding:
``The most comprehensible thing about the Universe is that it is
incomprehensible’’. A universe – any universe – is comprehensible because it
has been shaped by the human mind. Whereas the Universe is incomprehensible if
only because we can never grasp the entirety of a reality of which we are only
a part or an aspect. The Universe may comprehend itself, but not by means of
finite human minds.” Edward Harrison.
Education
First
Degree: Mathematics,
M.Sc.:
Astronomy,
Ph.D.:
Mathematical Physics and Cosmology,
Research interests
General
relativity, mathematical cosmology, differential geometry, dynamical systems,
history and philosophy of relativity and cosmology.
Courses
I currently
teach the following courses:
Mathematical Modelling
Mathematical Physics
Students
My current
PhD students are:
Ø George Kolionis
Ø Demetrios Trahilis
Ø Irene Evripidou
Ø Georgia Kittou*
Ø Andreas Paraskevopoulos
Ø Fotini Argiana*
(* official
acceptance pending)
Former PhD
students of mine include:
Ø Ifigeneia Klaoudatou
Ø John Miritzis
§
Our
group currently has two post doctoral fellows, Ifigeneia Klaoudatou and
Antonios Tsokaros.
MG12
This will
soon be a set of links to the parallel session on “Cosmological Singularities
and Asymptotics” to be held in
Selected Recent publications
1.
Slice energy in
higher order gravity theories and conformal transformations
S. Cotsakis, Grav. Cosm. 14 (2008) 176-183
2.
Talking About Singularities
S.
Cotsakis, In Proceedings of the MG11
Meeting, H. Kleinert, R. J. Jantzen and R. Ruffini, (World Scientific,
2008), pp. 758-68
3.
Braneworld cosmological
singularities
I.
Antoniadis, S. Cotsakis, I. Klaoudatou,
In Proceedings of the MG11 Meeting,
H. Kleinert, R. J. Jantzen and R. Ruffini, (World Scientific, 2008), pp. 2054-6
4.
Flat, radiation universes with
quadratic corrections and asymptotic analysis
S.
Cotsakis, A. Tsokaros, In Proceedings of
the MG11 Meeting, H. Kleinert, R. J. Jantzen and R. Ruffini, (World
Scientific, 2008), pp. 2045-7
Selected Older publications
1. Inflation
and the Conformal Structure of Higher-Order Gravity Theories.
J. D. Barrow and
2. Chaotic
Behaviour in Higher-Order Gravity Theories.
J. D. Barrow and
3. Self-Regenerating
Inflationary universe in higher-order gravity in arbitrary dimension.
J. D. Barrow and
4.
Quiescent
Self-Regenerating Universe.
S. Cotsakis, In Proceedings of the First
Greek Astronomical Meeting, P. Laskarides, (ed.), (
5. Conformal
Transformations Single Out a Unique Measure of Distance.
S. Cotsakis, Phys. Rev. D47 (1993) 1437-1439; Erratum:
Phys. Rev. D49
(1994) 1145
6. Mixmaster
Universe in Fourth-Order Gravity Theories.
S. Cotsakis, J. Demaret, Y. de Rop and L. Querella, Phys. Rev. D48 (1993) 4595–4603
7. Stability
of FRW Cosmology in Higher Order Gravity.
S. Cotsakis and G. Flessas, Phys. Rev. D48 (1993) 3577–3584.
8. Generalized
No-Hair Theorems.
S. Cotsakis and G. Flessas, Phys. Lett. B319 (1993) 69–73.
9. Painlev\'{e}
Analysis of the Mixmaster Universe.
S. Cotsakis and P. G. L. Leach, J.
Phys. A27 (1993) 1625–1631.
10. Power-Law
Inflation and Conformal Transformations.
S. Cotsakis and P. Saich, Class. Quant. Grav.
11 (1994) 383–387.
11. Escape
Rates for the Quiescent Self-Regenerating Universe.
S. Cotsakis, Phys. Lett. B328 (1994) 270–273.
12. Minimally
Coupled Scalar Field Wormholes.
S. Cotsakis, P. G. L. Leach and G. Flessas, Phys.
Rev. D49 (1994) 6489–6492.
13. Past-Instability
Conjecture and Cosmological Attractors in Generalized Isotropic Universes.
S. Cotsakis and G. Flessas, Phys. Rev. D51 (1995) 4160–4168.
14. Graviton
Creation and Conformal Non Invariance in Higher Order Gravity Theories.
S. Cotsakis and G. Flessas, Phys. Rev. D52 (1995) 5783–5786.
15. Reply
to Two Comments by Teyssandier and by Schmidt.
S. Cotsakis, Phys. Rev. D52 (1995) 6199–6200.
16. Non-Linear
Lagrangians and the Isotropy of the Universe.
J. Miritzis and S. Cotsakis, Phys.
Lett. B383 (1996) 377–382.
17. Adiabatic
Invariants and Mixmaster Catastrophes.
S. Cotsakis, R. Lemmer and P. G. L. Leach, Phys.
Rev. D57 (1998) 4691–4698.
18. Proof
of the Cosmic No-Hair Conjecture for Some Quadratic Homogeneous Cosmologies.
S. Cotsakis and J. Miritzis, Class.
Quant. Grav. 15 (1998) 2795–2801.
19. Symmetries
of homogeneous cosmologies.
S. Cotsakis, P.G.L. Leach and H. Pantazi, Grav.
Cosm. 4 (1998) 314–325.
20. Mathematical
problems in higher order gravity and cosmology.
S. Cotsakis, In Proceedings of the Eighth
Marcel Grossman Meeting on General Relativity, T.
Piran and R. Ruffini, eds., (World Scientific, 1999), pp. 505–507.
21. Variational
and conformal structure of nonlinear metric-connection gravitational
lagrangians.
S. Cotsakis, J. Miritzis and L. Querella, J.
Math. Phys. 40 (1999) 3063–3071.
22. Ever-Expanding,
Isotropizing, Quadratic Cosmologies.
S. Cotsakis, G.P. Flessas, P.G.L. Leach and L. Querella, Grav. Cosm. 6 (2000)
282–290.
J. Miritzis, P.G.L. Leach and S. Cotsakis, Grav.
Cosm. 6 (2000) 282-290.
P.G.L. Leach, S. Cotsakis and J. Miritzis, Grav.
Cosm. 7 (2001) 311–320.
25. Symmetries,
Singularities and Integrability in Nonlinear Mathematical Physics and
Cosmology.
S. Cotsakis and P. G. L. Leach, In Proceedings
of the Fourth International Conference on Symmetries in Nonlinear Mathematical
Physics, Proc. Inst. Math.
N.A.S. Ukraine
43 (2002) 128-135.
26. Algebraic
Integrability of FRW-Scalar Cosmologies.
S. Cotsakis and J. Miritzis, In Proceedings
of the Ninth Marcel Grossman Meeting on General Relativity, V. Gurzadyan, R.T. Jantzen and R. Ruffini (eds.) (World Scientific,
2002) pp. 1943-1945.
27. Scalar-Tensor
\sigma-Cosmologies.
S. Cotsakis and J. Miritzis, In Proceedings
of the Ninth Marcel Grossman Meeting on General Relativity, V. Gurzadyan, R.T. Jantzen and R. Ruffini (eds.) (World Scientific,
2002) pp. 1945-1947.
28. Current
Trends in Mathematical Cosmology.
S. Cotsakis, In Modern Theoretical and
Observational Cosmology,
29. A Note
on Wavemap-Tensor Cosmologies.
S. Cotsakis and J. Miritzis, In Modern
Theoretical and Observational Cosmology,
S. Cotsakis and P. G. L. Leach, In Cosmological
Crossroads, S. Cotsakis and E. Papantonopoulos (eds.),
(Springer, LNP592, 2002), pp. 3–15.
31. Cosmological
Singularities.
S. Cotsakis, In Cosmological Crossroads, S. Cotsakis and
32. Global
Hyperbolicity and Completeness.
Y. Choquet-Bruhat and
33. Completeness
Theorems in General relativity.
Y. Choquet-Bruhat and
34. Global
Hyperbolicity of Sliced Spaces.
S. Cotsakis, Gen. Rel. Grav. 36 (2004) 1183–1188.
35. Future
Singularities of Isotropic Cosmologies.
S. Cotsakis and
36. Modern
Approaches to Cosmological Singularities.
S. Cotsakis and
37. Slice
Energy and Theories of Gravitation.
S. Cotsakis, J. Phys. Conf. Ser.8 (2005) 39-48.
38. Singular
Isotropic Cosmologies and Bel-Robinson Energy.
S. Cotsakis and I. Klaoudatou, In the Proceedings of the A. Einstein
Century International Conference,
39. Cosmological
Singularities and Bel-Robinson Energy.
S. Cotsakis and
40. Future
Singularities and Completeness in Cosmology.
S. Cotsakis, In the Proceedings of the
41. The
Dominant Balance at Cosmological Singularities.
S. Cotsakis and J. D. Barrow, J. Phys. Conf. Ser. 68 (2007) 012004
42. Bel-Robinson
energy and the nature of singularities in isotropic cosmologies.
I. Klaoudatou and
43. Singularities
of varying light speed cosmologies.
J. Miritzis and
44.
Asymptotics of flat, radiation
universes in quadratic gravity.
S.
Cotsakis, A. Tsokaros, Phys. Lett.
B651 (2007) 341-344