1. Phase transitions in nuclei: from fission to multifragmentation and back F.Gulminelli – LPC Caen First multifragmentation models: ~1980 (L.Moretto, J.Randrup, J.Bondorf, D.Gross) First exclusive data on multifragmentation: ~1995 (ALADIN, EOS, INDRA, IsIs)

2. Multifragmentation: an extension of fission? J. A. LOPEZ and J. RANDRUP: Nucl. Phys. A512(1990)345; A571(1994)379 Extended fission coordinate in hyperspace Conjugated momentum Partition dependent multi-dimensional fission barrier Transition current and partial width  E* =E * q V

3. Multifragmentation: an extension of fission? J. A. LOPEZ and J. RANDRUP: Nucl. Phys. A512(1990)345; A571(1994)379 E* =E * Conditional saddle Scission -----------  Dissipation (Langevin) In principle, a very complex many-body dynamics: multi-dimensional deformations pre-saddle emission dissipation post-saddle emission

4. Multifragmentation: an extension of fission? J. A. LOPEZ and J. RANDRUP: Nucl. Phys. A512(1990)345; A571(1994)379 E* =E * Conditional saddle Scission -----------  Dissipation (Langevin) In principle, a very complex many-body dynamics: BUT: saddle very close to scission Saddle configurations

5. Multifragmentation: an extension of fission? E* L.Beaulieu et al, Phys.Rev.Lett. 84 (2000) 5971-5974  Experimental evidence: time plays no role in the multi-fragmentation regime

6. The liquid-gas phase transition of nuclear matter Gas Liquid Density   20200 MeV 1 5? QGP Temperature

7. The liquid-gas phase transition of nuclear matter Liquid Gas Density   20200 MeV 1 5? QGP Temperature Heavy Ions Collisions

8. The liquid-gas phase transition of nuclear matter Liquid Gas Density   20200 MeV 1 5? QGP Temperature Heavy Ions Collisions

9. Phase transitions in finite systems Landau Binder PRB 1984 L o order parameter M o L finite Field H Transition point

10. Phase transitions in finite systems Landau Binder PRB 1984 K.C.Lee PRE 1996 F.Gulminelli Ph.Chomaz PRE 2001 Physica A 2003 L o o L finite F M F M order parameter M Field H M F M P

11. M.Pichon et al. NPA 2006 Z1Z1 Z2Z2 197 Au Au+Au 80 A.MeV INDRA@GSI data Z 1 -Z 2 Z1Z1 Bimodalities in fragmentation distributions Largest fragment Z 1: typical order parameter in fragmentation phenomena

12. Lattice Gas Model : An exact model belonging to the LG Universality Class Liquid-Gas Transition versus data Independent of the incident energy => of the entrance channel dynamics Quantitative disagreement !! =E beam (MeV/A) E.Bonnet et al. 2008 Qualitative agreement 0.2.4 A/A s L G C

13. LGM with symmetry and Coulomb L G F G.Lehaut et al. 2008 Z=54 N=75

14. LGM with symmetry and Coulomb L G F 0..5 1 Z 1 /Z s 0..5 1 0..5 1 Z 1 /Z s G.Lehaut et al. 2008 Temperature

15. Nuclear statistical models : MMM Energy 1 2 3 4 Coulomb interaction V C 02468101214  C  N  Charged  C  Uncharged Spinodal 200 Pb F.Gulminelli et al. PRL91(2003)202701 ~Z 1

16. Nuclear statistical models: CTM G.Chaudhuri et al. nucl-ex 2008 uncharged charged uncharged

17. Conclusions  Charged systems at finite temperature have a generic fragmentation pattern with Z 1 ~Z tot /2, Z 2 ~Z 1  This hot (asymmetric) « fission » phenomenon can be interpreted as a first order transition  Contrary to fragmentation of neutral systems, this Coulomb-induced transition has no thermodynamic limit => it is not related to the LG universality class but closer to bimodality in fission  This may be what we experimentally observe through multi-fragmentation experiments (projectile fragmentation) (??)