Recent Progress and New Challenges in Isospin Physics with Heavy-Ion Reactions

We review the physics of helium nanodroplets with emphasis on theoretical aspects that have been the subject of recent research, like 3He and mixed 3He− 4He droplets, vortices in droplets and droplets on weakly attractive substrates, and in others that have not been previously reviewed in detail. Whenever possible, we compare results from different theoretical methods, with the aim of assessing the capabilities and limitations of the more phenomenological ones, that often constitute the only instrument to address some of the questions raised by current experiments.

Helium Nanodroplets: An Overview

The single-particle spectral functions in asymmetric nuclear matter are computed using the ladder approximation within the theory of finite temperature Green's functions. The internal energy and the momentum distributions of protons and neutrons are studied as a function of the density and the asymmetry of the system. The proton states are more strongly depleted when the asymmetry increases whereas the occupation of the neutron states is enhanced compared to the symmetric case. The self-consistent Green's function approach leads to slightly smaller energies compared to the Brueckner-Hartree-Fock approach. This effect increases with density and thereby modifies the saturation density and leads to smaller symmetry energies.

/pdf/correlations-in-hot-asymmetric-nuclear-matter-3deqj017xe.pdf

Correlations in hot asymmetric nuclear matter

Nuclear matter and finite nuclei exhibit the property of superfluidity by forming Cooper pairs. We review the microscopic theories and methods that are being employed to understand the basic properties of superfluid nuclear systems, with emphasis on the spatially extended matter encountered in neutron stars, supernova envelopes, and nuclear collisions. Our survey of quantum many-body methods includes techniques that employ Green functions, correlated basis functions, and Monte Carlo sampling of quantum states. With respect to empirical realizations of nucleonic and hadronic superfluids, this review is focused on progress that has been made toward quantitative understanding of their properties at the level of microscopic theories of pairing, with emphasis on the condensates that exist under conditions prevailing in neutron-star interiors. These include singlet S-wave pairing of neutrons in the inner crust, and, in the quantum fluid interior, singlet-S proton pairing and triplet coupled P-F-wave neutron pairing. Additionally, calculations of weak-interaction rates in neutron-star superfluids within the Green function formalism are examined in detail. We close with a discussion of quantum vortex states in nuclear systems and their dynamics in neutron-star superfluid interiors.

Superfluidity in nuclear systems and neutron stars

The authors use a model based on the Gross-Pitaevskii equation and quantum Monte-Carlo simulations, combined with experimental results, to show that quantum correlations in dipolar quantum droplets are not negligible and play a role in the onset of an observable shift in the critical atom number of the self-bound state.

Dilute dipolar quantum droplets beyond the extended Gross-Pitaevskii equation

Helium Liquids in Confined Geometries (C E Campbell) Monte Carlo Simulations at Zero Temperature: Helium in One, Two, and Three Dimensions (J Boronat) The Finite-Temperature Path Integral Monte Carlo Method and Its Application to Superfluid Helium Clusters (P Huang et al.) Structure and Dynamics of the Bulk Liquid and Bulk Mixtures (M Saarela et al.) A Microscopic View of Confined Quantum Liquids (V Apaja & E Krotscheck) Density Functional Descriptions of Liquid 3He in Restricted Geometries (E S Hernandez & J Navarro) Cavitation in Liquid Helium (M Barranco et al.) Excitations of Supefluid 4He in Confinement (B Fak & H R Glyde) Microscopic Superfluidity of Small 4He and Para-H2 Clusters Inside Helium Droplets (J P Toennies).

Microscopic Approaches to Quantum Liquids in Confined Geometries

Density functional theory microscopic description of quantum liquids the coupled cluster method and its application experiments with a Rubidium Bose-Einstein condensate theoretical aspects of Bose-Einstein condensation elementary excitations and dynamic structure of quantum fluids theory of correlated basis functions the magnetic susceptibility of liquid 3He the hyperspherical harmonic method - a review and some recent developments the nuclear many-body problem.

Eckhard Krotscheck

Papers

Microscopic Approaches to Quantum Liquids in Confined Geometries

Introduction to modern methods of quantum many-body theory and their applications

Theory of Correlated Basis Functions