相关论文: Coupled cluster approach to nuclear physics
We present the positron coupled cluster singles and doubles (POS-CCSD) method to calculate positron binding energies in molecules. This framework treats electrons and positrons on an equal footing and includes up to simultaneous…
Influence of surrounding matter on the properties of clusters is considered by an approach combining the methods of statistical and quantum mechanics. A cluster is treated as a bound N-particle system and surrounding matter as thermostat.…
The cluster structure of the neutron-rich isotope $^{10}$Be has been probed via the $(p,p\alpha)$ reaction at 150 MeV/nucleon in inverse kinematics and in quasifree conditions. The populated states of $^{6}$He residues were investigated…
The quest to understand multi-neutron systems has a long history, and recent experimental efforts aim to probe candidate four-neutron configurations in neutron-rich light nuclei such as ${}^8$He and ${}^7$H via quasi-free knockout…
The coupled cluster method is considered a gold standard in quantum chemistry, reliably giving energies that are exact within chemical accuracy (1.6 mHartree). However, even in the CCSD approximation, where the cluster operator is truncated…
A new linked cluster expansion for the calculation of ground state observables of complex nuclei with realistic interactions has been developed [1-3]; using the V8' potential [4] the ground state energy, density and momentum distribution of…
By analytically continuing the coupling constant $g$ of a coupled quantum theory, one can, at least in principle, arrive at a state whose energy is lower than the ground state of the theory. The idea is to begin with the uncoupled $g=0$…
We introduce a unitary coupled-cluster (UCC) ansatz termed $k$-UpCCGSD that is based on a family of sparse generalized doubles (D) operators which provides an affordable and systematically improvable unitary coupled-cluster wavefunction…
A version of the method of accurate calculations for few valence-electron atoms which combines linearized single-double coupled cluster method with the configuration interaction technique is presented. The use of the method is illustrated…
We compute ground-state and dynamical properties of $^4$He and $^{16}$O nuclei using as input high-resolution, phenomenological nucleon-nucleon and three-nucleon forces that are local in coordinate space. The nuclear Schr\"odinger equation…
Ionization rates and Stark shifts of H$_2$, CO, O$_2$, H$_2$O, and CH$_4$ in static electric fields have been computed with coupled-cluster methods in a basis set of atom-centered Gaussian functions with complex-scaled exponent.…
Minimum energy conical intersections can be used to rationalize photochemical processes. In this Letter, we examine an algorithm to locate these structures that does not require the evaluation of nonadiabatic coupling vectors, showing that…
The Borromean $^6$He nucleus is an exotic system characterized by two `halo' neutrons orbiting around a compact $^4$He (or $\alpha$) core, in which the binary subsystems are unbound. The simultaneous reproduction of its small binding energy…
Configuration interaction (CI) calculations in atoms with two valence electrons, carried out in the V(N-2) Hartree-Fock potential of the core, are corrected for core-valence interactions using many-body perturbation theory (MBPT). Two…
The correlated basis function theory is applied to the study of medium-heavy doubly closed shell nuclei with different wave functions for protons and neutrons and in the jj coupling scheme. State dependent correlations including tensor…
A practical high-accuracy relativistic method of atomic structure calculations for univalent atoms is presented. The method is rooted in the coupled-cluster formalism and includes non-perturbative treatment of single and double excitations…
The distinguishable cluster approximation applied to coupled cluster doubles equations greatly improves absolute and relative energies. We apply the same approximation to the triples equations and demonstrate that it can also improve…
Excited states of $^4$He are studied in four-body calculations with explicitly correlated Gaussian bases. All the levels below $E_{\rm x}$=26 MeV are reproduced reasonably well using realistic potentials. An analysis is made to show how the…
In this thesis, the ground state properties of nuclear matter, namely the energy per particle and the response to weak probes, are computed, studying the effects of three nucleon interactions. Both the variational approach, based on the…
We present calculations of various electroweak response functions for the 16O nucleus obtained using coupled-cluster theory in conjunction with the Lorentz integral transform method. We employ nuclear forces derived at next-to-leading order…