title: Nuclear Binding Near a Quantum Phase Transition.
abstract: How do protons and neutrons bind to form nuclei? This is the central question of ab initio nuclear structure theory. While the answer may seem as simple as the fact that nuclear forces are attractive, the full story is more complex and interesting. In this work we present numerical evidence from ab initio lattice simulations showing that nature is near a quantum phase transition, a zero-temperature transition driven by quantum fluctuations. Using lattice effective field theory, we perform Monte Carlo simulations for systems with up to twenty nucleons. For even and equal numbers of protons and neutrons, we discover a first-order transition at zero temperature from a Bose-condensed gas of alpha particles (^{4}He nuclei) to a nuclear liquid. Whether one has an alpha-particle gas or nuclear liquid is determined by the strength of the alpha-alpha interactions, and we show that the alpha-alpha interactions depend on the strength and locality of the nucleon-nucleon interactions. This insight should be useful in improving calculations of nuclear structure and important astrophysical reactions involving alpha capture on nuclei. Our findings also provide a tool to probe the structure of alpha cluster states such as the Hoyle state responsible for the production of carbon in red giant stars and point to a connection between nuclear states and the universal physics of bosons at large scattering length.
authors.affiliation: Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany.
authors.forename: Serdar
authors.initials: S
authors.lastname: Elhatisari
authors.affiliation: Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44870 Bochum, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Rokash
authors.affiliation: Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany.
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Alarcón
authors.affiliation: Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Dechuan
authors.initials: D
authors.lastname: Du
authors.affiliation: Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Klein
authors.affiliation: Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Bing-Nan
authors.initials: BN
authors.lastname: Lu
authors.affiliation: Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany.|Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich, Germany.|JARA-High Performance Computing, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Ulf-G
authors.initials: UG
authors.lastname: Meißner
authors.affiliation: Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44870 Bochum, Germany.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Epelbaum
authors.affiliation: Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44870 Bochum, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Krebs
authors.affiliation: Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Timo A
authors.initials: TA
authors.lastname: Lähde
authors.affiliation: Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: Dean
authors.initials: D
authors.lastname: Lee
authors.affiliation: Department of Physics and Astronomy and HPC2 Center for Computational Sciences, Mississippi State University, Mississippi State, Mississippi 39762, USA.
authors.forename: Gautam
authors.initials: G
authors.lastname: Rupak