Microscopic description of pair transfer between two superfluid Fermi systems: combining phase-space averaging and combinatorial techniques

Abstract

In a mean-field description of superfluidity, particle number and gauge angle are treated as quasi-classical conjugated variables. This level of description was recently used to describe nuclear reactions around the Coulomb barrier. Important effects of the relative gauge angle between two identical superfluid nuclei (symmetric collisions) on transfer probabilities and fusion barrier have been uncovered. A theory making contact with experiments should at least average over different initial relative gauge-angles. In the present work, we propose a new approach to obtain the multiple pair transfer probabilities between superfluid systems. This method, called Phase-Space combinatorial (PSC) technique, relies both on phase-space averaging and combinatorial arguments to infer the full pair transfer probability distribution at the cost of multiple mean-field calculations only. After benchmarking this approach in a schematic model, we apply it to the collision ${}^{20}$O+${}^{20}$O at various energies below the Coulomb barrier. The predictions for one pair transfer are similar to results obtained with an approximated projection method whereas significant differences are found for two pairs transfer. Finally, we investigated the applicability of the PSC method to the contact between non-identical superfluid systems. [...] The applicability of the PSC method to asymmetric nuclear collisions is investigated for the ${}^{14}$O+${}^{20}$O collision and it turns out that unrealistically small single- and multiple-pair transfer probabilities are obtained. [...] We conclude that the best ground for probing gauge-angle effects in nuclear reaction and/or for applying the proposed PSC approach on pair transfer is the collisions of identical open-shell spherical nuclei.

References in corpus (7)

• Particle transfer reactions with the time-dependent Hartree-Fock theory using a particle number projection technique
• A Stochastic Mean-Field Approach For Nuclear Dynamics
• Pairing Vibrations Study with the Time-Dependent Hartree-Fock-Bogoliubov theory
• Thermodynamics of pairing in mesoscopic systems
• Transfer probabilities for the reactions ${}^{14,20}$O+${}^{20}$O in terms of multiple time-dependent Hartree-Fock-Bogoliubov trajectories
• Dynamics of Fragmented Condensates and Macroscopic Entanglement
• From bare to renormalized order parameter in gauge space: structure and reactions

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• Density-constraint Time-dependent Hartree-Fock-Bogoliubov method
• Examining empirical evidence of the effect of superfluidity on the fusion barrier
• Nuclear Quantum Many-Body Dynamics: From Collective Vibrations to Heavy-Ion Collisions (2nd edition)
• Combining phase-space and time-dependent reduced density matrix approach to describe the dynamics of interacting fermions
• Multiconfigurational time-dependent density functional theory for atomic nuclei: Technical and numerical aspects
• Counting statistics in finite Fermi systems: illustrations with the atomic nucleus
• Microscopic Theory of Nuclear Fission
• Emulation of large-scale qubit registers with a phase-space approach