Relevance of equilibrium in multifragmentation

Abstract

The relevance of equilibrium in a multifragmentation reaction of very central ${}^{40}Ca{+}^{40}Ca$ collisions at 35 MeV/nucleon is investigated by using simulations of Antisymmetrized Molecular Dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time $t$ in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble which well reproduces the reaction ensemble at each reaction time $t$ for the investigated period $80\le t\le 300$ fm/$c$. However, there are some other observables which show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables.

13 pages and 12figures; added a few sentences and corrected typos, accepted in Phys. Rev. C

References in corpus (36)

• Determination of the Equation of State of Dense Matter
• Determination of the stiffness of the nuclear symmetry energy from isospin diffusion
• Isospin Fractionation in Nuclear Multifragmentation
• Caloric curves and critical behavior in nuclei
• Negative heat capacity in the critical region of nuclear fragmentation: an experimental evidence of the liquid-gas phase transition
• Central Collisions of Au on Au at 150, 250 and 400 A MeV
• The liquid to vapor phase transition in excited nuclei
• Antisymmetrized molecular dynamics with quantum branching processes for collisions of heavy nuclei
• Thermodynamical features of multifragmentation in peripheral Au + Au Collisions at 35 A.MeV
• Modelization of the EOS
• Statistical Multifragmentation in Central Au+Au Collisions at 35 MeV/u
• Phase Transitions in "Small" systems
• Antisymmetrized molecular dynamics of wave packets with stochastic incorporation of Vlasov equation
• Systematics of Stopping and Flow in Au+Au Collisions
• Reaction Dynamics and Multifragmentation in Fermi Energy Heavy Ion Reactions
• Symmetry energy for fragmentation in dynamical nuclear collisions
• Compatibility of localized wave packets and unrestricted single particle dynamics for cluster formation in nuclear collisions
• Deformation of C isotopes
• Study of intermediate velocity products in the Ar+Ni collisions between 52 and 95 A.MeV
• Isospin Effects in Nuclear Multifragmentation
• Nucleon Flow and Fragment Flow in Heavy Ion Reactions
• Searching for the statistically equilibrated systems formed in heavy ion collisions
• Statistical description of nuclear break-up
• INCORPORATION OF QUANTUM STATISTICAL FEATURES IN MOLECULAR DYNAMICS
• Statistical properties of antisymmetrized molecular dynamics for non-nucleon-emission and nucleon-emission processes
• Fragmentation path of excited nuclear systems
• Geometric Foundation of Thermo-Statistics, Phase Transitions, Second Law of Thermodynamics, but without Thermodynamic Limit
• Equilibrium under flow
• Improvement of the nucleon emission process and the statistical property in molecular dynamics
• Inclusion of Quantum Fluctuations in Wave Packet Dynamics
• Short timescale behavior of colliding heavy nuclei at intermediate energies
• Links Between Heavy Ion and Astrophysics
• Multifragmentation and the liquid-gas phase transition: an experimental overview
• Statistical analysis of a dynamical multifragmentation path
• Searching for statistical equilibrium in a dynamical multifragmentation path
• Extended Gibbs ensembles with flow

Cited by in corpus (9)

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• Fragmentation paths in dynamical models
• Experimental reconstruction of primary hot isotopes and characteristic properties of the fragmenting source in the heavy ion reactions near the Fermi energy
• Influence of fast emissions and statistical de-excitation on the isospin transport ratio
• Isospin compositions of correlated sources in the Fermi energy domain
• Statistical analysis of experimental multifragmentation events in ${}^{64}$Zn + ${}^{112}$Sn at 40 MeV/nucleon
• Investigation of the nuclear liquid-gas phase transition in the static AMD
• Symmetry energy from fragment observables in the canonical thermodynamic model
• High density matter