A brief description of the novel approach towards solving few-body scattering problems in a finite-dimensional functional space of the $L_2$-type is presented. The method is based on the complete few-body continuum discretization in the basis of stationary wave packets. This basis, being transformed to the momentum representation, leads to the cell-lattice-like discretization of the momentum space. So the initial scattering problem can be formulated on the multi-dimensional momentum lattice which makes it possible to reduce the solution of any scattering problem above the breakup threshold (where the integral kernels include, in general, some complicated moving singularities) to convenient simple matrix equations which can be solved on the real energy axis. The phase shifts and inelasticity parameters for the three-body $nd$ elastic scattering with MT I-III $NN$ potential both below and above the three-body breakup threshold calculated with the proposed wave-packet technique are in a very good agreement with the previous accurate benchmark calculation results.
The four-body bound state with two-body forces is formulated by the Three-Dimensional approach, which greatly simplifies the numerical calculations of few-body systems without performing the Partial Wave components. We have obtained the Yakubovsky equations directly as three dimensional integral equations.
Two-body scattering is studied by solving the Lippmann-Schwinger equation in momentum space without angular-momentum decomposition for a local spin dependent short range interaction plus Coulomb. The screening and renormalization approach is employed to treat the Coulomb interaction. Benchmark calculations are performed by comparing our procedure with partial-wave calculations in configuration space for p-10Be, p-16O and 12C-10Be elastic scattering, using a simple optical potential model.
Heavy quark drag coefficients in the quark-gluon plasma are evaluated in the perturbative QCD. It is found that for charm quarks the contribution from three-body elastic scattering is comparable to those from two-body elastic and radiative scatterings while for bottom quarks it becomes dominant. Using a schematic expanding fireball model, effects of both two-body and three-body scatterings on the transverse momentum spectra of heavy quarks produced in Au+Au collisions at center of mass energy $\sqrt{s_{NN}}=200$ GeV are studied. Results on electrons from resulting heavy meson decays are compar…
Three-dimensional (3D) Faddeev integral equations are solved for three-body (3B) bound state problem without using the partial wave (PW) form of low momentum two-body (2B) interaction $V_{low-k}$ which is constructed from spin independent Malfliet-Tjon V (MT-V) potential. The dependence of 3B binding energy on the cutoff momentum of $V_{low-k}$ is investigated for a wide range of $Λ$ from $1.0$ to $7.0\, fm^{-1}$. The properties of Faddeev components and 3B wave function are displayed and the effect of number of grid points for momentum and angle variables on the accuracy and the stability of …
We present a method based on hyperspherical harmonics to solve the nuclear many-body problem. It is an extension of accurate methods used for studying few-body systems to many bodies and is based on the assumption that nucleons in nuclei interact mainly via pairwise forces.This leads to a two-variable integro-differential equation which is easy to solve. Unlike methods that utilize effective interactions, the present one employs directly nucleon-nucleon potentials and therefore nuclear correlations are included in an unambiguous way. Three body forces can also be included in the formalism. Det…
We propose a simple approach to predict the angular momentum I ground state (I g.s.) probabilities of many-body systems that does not require the diagonalization of hamiltonians with random interactions. This method is found to be applicable to {\bf all} cases that have been discussed: even and odd fermion systems (both in single-j and many-j shells), and boson (both sd and sdg) systems. A simple relation for the highest angular momentum g.s. probability is found. Furthermore, it is suggested for the first time that the 0g.s. dominance in boson systems and in even-fermion systems is given by t…
We derive general expressions for non-energy weighted and energy-weighted cluster sum rules for systems of three charged particles. The interferences between pairs of particles are found to play a substantial role. The energy-weighted sum rule is usually determined by the kinetic energy operator, but we demonstrate that it has similar additional contributions from the angular momentum and parity dependence of two- and three-body potentials frequently used in three-body calculations. The importance of the different contributions is illustrated with the dipole excitations in $^6$He. The results …
Momentum distributions of particles from nuclear break-up of fast three-body halos are calculated consistently, and applied to $^{11}$Li. The same two-body interactions between the three particles are used to calculate the ground state structure and the final state of the reaction processes. We reproduce the available momentum distributions from $^{11}$Li fragmentation, together with the size and energy of $^{11}$Li, with a neutron-core relative state containing a $p$-state admixture of 20\%-30\%. The available fragmentation data strongly suggest an $s$-state in $^{10}$Li at about 50 keV, and …
Analytical expressions of the one- and two- body terms in the cluster expansion of the one-body density matrix and momentum distribution of the s-p and s-d shell nuclei with N=Z are derived. They depend on the harmonic oscillator parameter b and the parameter $β$ which originates from the Jastrow correlation function. These parameters have been determined by least squares fit to the experimental charge form factors. The inclusion of short-range correlations increases the high momentum component of the momentum distribution, $n({\bf k})$ for all nuclei we have considered while there is an A dep…
Realistic NN interactions and many-body approaches have been used to calculate ground-state properties of nuclei with A=3, 4, 12, 16, 40, with particular emphasis on various kinds of momentum distributions. It is shown that at proper values of the relative (rel) and center-of-mass (c.m.) momenta, the two-nucleon momentum distribution n_A^{N_1N_2} (k_{rel}, K_{c.m.}, θ) exhibits the property of factorization, namely n_A^{N_1N_2} (k_{rel}, K_{c.m.}, θ) \simeq n_{rel}(k_{rel}) n_(c.m.)( K{c.m.}). The factorization of the momentum distributions , bearing a universal character, results from a gener…
The two-body momentum distribution n2(p1,p2) of nuclei is studied. First, a compact analytical expression is derived for Z=N l-closed nuclei, within the context of the independent-particle shell model. Application to the light closed-shell nucleus 16O is included and discussed. Next, the effect of dynamical, short-range correlations is investigated in the case of 4He, by including Jastrow-type correlations in the formalism. The effect is significant for large values of p1 and p2 and for angles between the vectors p1 and p2 close to 180 deg. and 0.
Momentum distributions of particles from nuclear break-up of fast three-body halos are calculated incorporating effects of final state interactions. The same two-body interactions between the particles are used to calculate both the ground state structure and the final state of the reaction processes. The ground state wave function reproduces size and energy of the halo nucleus. First we give a general and detailed description of the method. Then we investigate the effect of final state interactions in neutron removal and core break-up reactions for one- and two-dimensional momentum distributi…
In this paper, we discuss the angular momentum distribution in the ground states of many-body systems interacting via a two-body random ensemble. Beginning with a few simple examples, a simple approach to predict P(I)'s, angular momenta I ground state (g.s.) probabilities, of a few solvable cases, such as fermions in a small single-j shell and d boson systems, is given. This method is generalized to predict P(I)'s of more complicated cases, such as even or odd number of fermions in a large single-j shell or a many-j shell, d-boson, sd-boson or sdg-boson systems, etc. By this method we are able…
Universality of short range correlations has been investigated both in coordinate and in momentum space, by means of one-and two-body densities and momentum distributions. In this contribution we discuss one- and two-body momentum distributions across a wide range of nuclei and their common features which can be ascribed to the presence of short range correlations. Calculations for few-body nuclei, namely 3He and 4He, have been performed using exact wave functions obtained with Argonne nucleon-nucleon interactions, while the linked cluster expansion technique is used for medium-heavy nuclei. T…
The two-body t-matrix is calculated directly as function of two vector momenta for different Malfliet-Tjon type potentials. At a few hundred MeV projectile energy the total amplitude is quite a smooth function showing only a strong peak in forward direction. In contrast the corresponding partial wave contributions, whose number increases with increasing energy, become more and more oscillatory with increasing energy. The angular and momentum dependence of the full amplitude is studied and displayed on as well as off the energy shell as function of positive and negative energies. The behavior o…
We investigate two simple prescriptions to account for the Pauli principle in a three-body cluster model employing a new method based on an adiabatic hyperspherical expansion to solve the Faddeev equations in coordinate space. The resulting wave functions are computed and compared. They are furthermore tested on halo nuclei by calculations of momentum distributions and invariant mass spectra arising after fragmentation of fast $^6$He and $^{11}$Li in collisions with light targets. The prescriptions are very accurate and the available measured quantities are remarkably well reproduced when fina…
Current and future electron and neutrino scattering experiments will be greatly aided by a better understanding of the role played by short-range correlations in nuclei. Two-body physics, including nucleon-nucleon correlations and two-body electroweak currents, is required to explain the body of experimental data for both static and dynamical nuclear properties. In this work, we focus on examining nucleon-nucleon correlations from a chiral effective field theory perspective and provide a comprehensive set of new variational Monte Carlo calculations of one- and two-body densities and momentum d…
A particular three-body mechanism is responsible for the missing strength which has been reported in $^3$He(e,e$'$p) reactions at missing momentum above 700 MeV/c. It corresponds to the absorption of the virtual photon by a nucleon at rest which subsequently propagates on-shell and emits a meson which is reabsorbed by the pair formed by the two other nucleons. Its amplitude, which is negligible in photon induced reactions as well as in the electro-production of an on-shell meson, becomes maximal in the quasi-free kinematics (X=1). It relates the amplitude of the $^3$He(e,e$'$p)D reaction to th…
The Faddeev equations for the three body bound state are solved directly as three dimensional integral equation without employing partial wave decomposition. The numerical stability of the algorithm is demonstrated. The three body binding energy is calculated for Malfliet-Tjon type potentials and compared with results obtained from calculations based on partial wave decomposition. The full three body wave function is calculated as function of the vector Jacobi momenta. It is shown that it satisfies the Schrödinger equation with high accuracy. The properties of the full wave function are displa…
In this paper, we discuss the regularities of energy of each angular momentum $I$ averaged over all the states for a fixed angular momentum (denoted as $\bar{E}_I$'s) in many-body systems interacting via a two-body random ensemble. It is found that $\bar{E}_I$'s with $I \sim I_{min}$ (minimum of $I$) or $I_{max}$ have large probabilities (denoted as ${\cal P}(I)$) to be the lowest, and that ${\cal P}(I)$ is close to zero elsewhere. A simple argument based on the randomness of the two-particle cfp's is given. A compact trajectory of the energy $\bar{E}_I$ vs. $I(I+1)$ is found to be robust. Reg…
Short-range correlations in 4He are investigated using many-body wave functions obtained in the no-core shell model. The similarity renormalization group (SRG) is used to evolve the Argonne V8' interaction and the density operators. The effects of short-range correlations are reflected in the two-body densities in coordinate space as a function of the distance between two nucleons, or alternatively in in momentum space as function of the relative momentum between two nucleons. The SRG transformation is performed in two-body approximation. The importance of missing three-body and higher-body co…
The complex-rotated hyperspherical adiabatic method is used to study the decay of low-lying $^9$Be and $^9$B resonances into $α$, $α$ and $n$ or $p$. We consider six low-lying resonances of $^9$Be ($1/2^\pm$, $3/2^\pm$ and $5/2^\pm$) and one resonance of $^9$B ($5/2^-$) to compare with. The properties of the resonances at large distances are decisive for the momentum distributions of the three decaying fragments. Systematic detailed energy correlations of Dalitz plots are presented.
The effects of short range correlations (SRC) in inclusive (A(e,e')X) and exclusive (A(e,e'N)X and A(e,e'2N)X) are reviewed. A new approach to the analysis of inclusive cross sections is illustrated, based upon the introduction of proper scaling functions and variables which incorporate the effects of two- and three-nucleon SRC. The approach is used to interpret the plateaux observed in the CLAS inclusive cross section ratios of 4He, 12C and 56Fe to 3He.
The effective low-momentum interaction Vlowk is applied to three- and four-nucleon systems. We investigate the 3H, 3He and 4He binding energies for a wide range of the momentum cutoffs. By construction, all low-energy two-body observables are cutoff-independent, and therefore, any cutoff dependence is due to missing three-body or higher-body forces. We argue that for reasonable cutoffs Vlowk is similar to high-order interactions derived from chiral effective field theory. This motivates augmenting Vlowk by corresponding three-nucleon forces. The set of low-momentum twoand three-nucleon forces …
We are developing a covariant model for all mesons that can be described as quark-antiquark bound states in the framework of the Covariant Spectator Theory (CST) in Minkowski space. The kernel of the bound-state equation contains a relativistic generalization of a linear confining potential which is singular in momentum space and makes its numerical solution more difficult. The same type of singularity is present in the momentum-space Schrödinger equation, which is obtained in the nonrelativistic limit. We present an alternative, singularity-free form of the momentum-space Schrödinger equation…
Nowadays quantum-mechanical theory allows one to reliably calculate the processes of 2p radioactivity (true three-body decays) and the corresponding energy and angular correlations up to distances of the order of 1000 fm. However, the precision of modern experiments has now become sufficient to indicate some deficiency of the predicted theoretical distributions. In this paper we discuss the extrapolation along the classical trajectories as a method to improve the convergence of the theoretical energy and angular correlations at very large distances (of the order of atomic distances), where onl…
Background: The numerical solution of few-body scattering problems with realistic interactions is a difficult problem that normally must be solved on powerful supercomputers, taking a lot of computer time. This strongly limits the possibility of accurate treatments for many important few-particle problems in different branches of quantum physics. Purpose: To develop a new general highly effective approach for the practical solution of few-body scattering equations that can be implemented on a graphics processing unit. Methods: The general approach is realized in three steps: (i) the reformulat…
A method is presented for the calculation of the one-body and two-body density matrices and their Fourier transforms in momentum space, that is consistent with the requirement for translational invariance, in the case of a nucleus (a finite self-bound system). We restore translational invariance by using the so-called fixed center-of-mass approximation for constructing an intrinsic nuclear ground state wavefunction by starting from a non-translationally invariant wavefunction and applying a projection prescription. We discuss results for the one-body and two-body momentum distributions of the …
The scalar three-body Bethe-Salpeter equation, with zero-range interaction, is solved in Minkowski space by direct integration of the four-dimensional integral equation. The singularities appearing in the propagators are treated properly by standard analytical and numerical methods, without relying on any ansatz or assumption. The results for the binding energies and transverse amplitudes are compared with the results computed in Euclidean space. A fair agreement between the calculations is found.
By decomposing the important sampled imaginary time Schrödinger evolution operator to fourth order with positive coefficients, we derived a number of distinct fourth order Diffusion Monte Carlo algorithms. These sophisticated algorithms require higher derivatives of the drift velocity and local energy and are more complicated to program. However, they allowed very large time steps to be used, converged faster with lesser correlations, and virtually eliminated the step size error. We demonstrated the effectiveness of these quartic algorithms by solving for the ground state properties of bulk li…
Momentum distributions of particles from nuclear break-up of fast three-body halos are calculated for polarized beam and outgoing fragments. These momentum distributions are combined in observable quantities which emphasize the two-body correlations in the initial three-body structure as well as in the final two-body system. Applying the formalism to 11Li we find a sensitive dependence on the p-wave content and on the position of the p-resonances in 10Li. Polarization experiments are then a new tool to study correlations in nuclear halos.
$\mathbf{Background:}$ Realistic nucleon-nucleon interactions induce short-range correlations in nuclei. To solve the many-body problem unitary transformations like the similarity renormalization group (SRG) are often used to soften the interactions. $\mathbf{Purpose:}$ Two-body densities can be used to illustrate how the SRG eliminates short-range correlations in the wave function. The short-range information can however be recovered by transforming the density operators. $\mathbf{Method:}$ The many-body problem is solved for $^4$He in the no core shell model (NCSM) with SRG transformed AV8' …
An exact treatment of the operators Q/e(ω) and the total momentum is adopted to solve the nuclear matter Bruecker-Bethe-Goldstone equation with two- and three-body forces. The single-particle potential, equation of state and nucleon effective mass are calculated from the exact G-matrix. The results are compared with those obtained under the angle-average approximation and the angle-average approximation with total momentum approximation. It is found that the angle-average procedure, whereas preventing huge calculations of coupled channels, nevertheless provides a fairly accurate approximation.…
We present a systematically improvable method for numerically solving relativistic three-body integral equations for the partial-wave projected amplitudes. The method consists of a discretization procedure in momentum space, which approximates the continuum problem with a matrix equation. It is solved for different matrix sizes, and in the end, an extrapolation is employed to restore the continuum limit. Our technique is tested by solving a three-body problem of scalar particles with an $S$ wave two-body bound state. We discuss two methods of incorporating the pole contribution in the integral…
A novel approach to solve the Faddeev equation for three-body scattering at arbitrary energies is proposed. This approach disentangles the complicated singularity structure of the free three-nucleon propagator leading to the moving and logarithmic singularities in standard treatments. The Faddeev equation is formulated in momentum space and directly solved in terms of momentum vectors without employing a partial wave decomposition. In its simplest form the Faddeev equation for identical bosons, which we are using, is an integral equation in five variables, magnitudes of relative momenta and an…
In this paper, we study the relativistic effects in a three-body bound state. For this purpose, the relativistic form of the Faddeev equations is solved in momentum space as a function of the Jacobi momentum vectors without using a partial wave decomposition. The inputs for the three-dimensional Faddeev integral equation are the off-shell boost two-body $t-$matrices, which are calculated directly from the boost two-body interactions by solving the Lippmann-Schwinger equation. The matrix elements of the boost interactions are obtained from the nonrelativistic interactions by solving a nonlinear…
Angular-momentum or parity-dependent nonlocal optical potentials for nucleon-${}^{16}\mathrm{O}$ scattering able to fit differential cross section data over the whole angular regime are developed and applied to the description of deuteron-${}^{16}\mathrm{O}$ scattering in the framework of three-body Faddeev-type equations for transition operators. Differential cross sections and deuteron analyzing powers for elastic scattering and ${}^{16}\mathrm{O}(d,p){}^{17}\mathrm{O}$ transfer reactions are calculated using a number of local and nonlocal optical potentials and compared with experimental da…
We calculate momentum distributions of neutrons and protons in $^3$He in the framework of a model which includes 3N interactions together with 2N interactions. It is shown that contribution of 3N interactions becomes essential in comparison with contribution coming from 2N interaction for internal momentum in $^3$He $k>$~250~MeV/c. We also compare calculated momentum distribution of protons with so-called empirical momentum distribution of protons extracted from A$(^3\mathrm{He},p)$ breakup cross-sections measured for protons emitted at zero degree. It is concluded that 3N interactions cannot …
These notes were written for a set of three lectures given in a school at the Max Planck Institute for the Physics of Complex Systems in October/2017 before the workshop "Critical Stability of Quantum Few-Body Systems". These lectures are primarily dedicated to the students and represent a very idiosyncratic vision of the author, mainly in the last part of the text related to applications. These notes are only a tentative to show a technique, among many others, to solve problems in a very rich area of the contemporary physics - the Few-Body Physics - many times unknown by a considerable part o…
Poincare' covariant definitions for the spin-dependent spectral function and for the momentum distributions within the light-front Hamiltonian dynamics are proposed for a three-fermion bound system, starting from the light-front wave function of the system. The adopted approach is based on the Bakamjian-Thomas construction of the Poincare' generators, that allows one to easily import the familiar and wide knowledge on the nuclear interaction into a light-front framework. The proposed formalism can find useful applications in refined nuclear calculations, like the ones needed for evaluating the…
We have investigated the three-body force (TBF) effect on the neutron and proton momentum distributions in asymmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach by adopting the $AV18$ two-body interaction plus a microscopic TBF. In asymmetric nuclear matter, it is shown that the neutron and proton momentum distributions become different from their common distribution in symmetric nuclear matter. The predicted depletion of the proton hole states increases while the neutron one decreases as a function of isospin-asymmetry. The TBF effect on the neutron an…
Relation to a property of the angular momentum zero space of states of four fermions in an angular momentum $j = 9/2$ shell unexpectedly found to be stationary for any rotationally invariant two-body interaction
The open dynamics of quantum many-body systems involve not only the exchange of energy, but also of other conserved quantities, such as momentum. This leads to additional decoherence, which may have a profound impact in the dynamics. Motivated by this, we consider a many-body system subject to total momentum dephasing and show that under very general conditions this leads to a diffusive component in the dynamics of any local density, even far from equilibrium. Such component will usually have an intricate interplay with the unitary dynamics. To illustrate this, we consider the case of a superf…
In many so-called "beyond-mean-field" many-body methods, one creates symmetry-breaking states and then projects out states with good quantum number(s); the most important example is angular momentum. Motivated by the computational intensity of symmetry restoration, we investigate the numerical convergence of two competing methods for angular momentum projection with rotations over Euler angles, the textbook-standard projection through quadrature, and a recently introduced projection through linear algebra. We find well-defined patterns of convergence with increasing number of mesh points (for …
Systems consisting of identical bosons with a large scattering length satisfy universal relations determined by 2-body physics that are similar to those for fermions with two spin states. They require the momentum distribution to have a large-momentum 1/k^4 tail and the radio-frequency transition rate to have a high-frequency 1/omega^{3/2} tail, both of which are proportional to the 2-body contact. Identical bosons also satisfy additional universal relations that are determined by 3-body physics and involve the 3-body contact, which measures the probability of 3 particles being very close toge…
We investigate event-by-event fluctuations for ensembles with non-fixed multiplicity. Moments of event observable distributions, like total energy distribution, total transverse momentum distribution, etc, are shown to be related to the multi-body correlations present in the system. For classical systems, these moments reduce in the absence of any correlations to the moments of particle inclusive momentum distribution. As a consequence, a zero value for the recently introduced $Φ$-variable is shown to indicate the vanishing of two-body correlations from one part, and of correlations between mu…
A generalized contour deformation method (GCDM) which combines complex rotation and translation in momentum space, is discussed. GCDM gives accurate results for bound, virtual (antibound), resonant and scattering states starting with a realistic nucleon-nucleon interaction. It provides a basis for full off-shell $t$-matrix calculations both for real and complex input energies. Results for both spectral structures and scattering amplitudes compare perfectly well with exact values for the separable Yamaguchi potential. Accurate calculation of virtual states in the Malfliet-Tjon and the realistic…
We study the evolution from few- to many-body physics of fermionic systems in one spatial dimension with attractive pairwise interactions. We determine the detailed form of the momentum distribution, the structure of the one-body density matrix, and the pairing properties encoded in the two-body density matrix. From the low- and high-momentum scaling behavior of the single-particle momentum distribution we estimate the speed of sound and Tan's contact, respectively. Both quantities are found to be in agreement with previous calculations. Based on our calculations of the one-body density matric…
A first step toward a universal nuclear energy density functional based on low-momentum interactions is taken using the density matrix expansion (DME) of Negele and Vautherin. The DME is adapted for non-local momentum-space potentials and generalized to include local three-body interactions. Different prescriptions for the three-body DME are compared. Exploratory results are given at the Hartree-Fock level, along with a roadmap for systematic improvements within an effective action framework for Kohn-Sham density functional theory.
The adaptation of Wigner's induced representation for a relativistic quantum theory making possible the construction of wavepackets and admitting covariant expectation values for the coordinate operator x^μintroduces a foliation on the Hilbert space of states. The spin-statistics relation for fermions and bosons implies the universality of the parametrization of orbits of the induced representation, implying that all particles within the identical particle sets transform under the same SU(2) subgroup of the Lorentz group, and therefore their spins and angular momentum states can be computed us…
Photon absorption by a quark in one nucleon followed by its high momentum transfer interaction with a quark in the other may produce two final-state nucleons with high relative momentum. We sum the relevant quark rescattering diagrams, to show that the scattering amplitude depends on a convolution between the large angle $pn$ scattering amplitude, the hard photon-quark interaction vertex and the low-momentum deuteron wave function. The computed absolute values of the cross section are in reasonable agreement with the data.
The first step toward the application of an effective non partial wave (PW) numerical approach to few-body atomic bound states has been taken. The two-body transition amplitude which appears in the kernel of three-dimensional Faddeev-Yakubovsky integral equations is calculated as function of two-body Jacobi momentum vectors, i.e. as a function of the magnitude of initial and final momentum vectors and the angle between them. For numerical calculation the realistic interatomic interactions HFDHE2, HFD-B, LM2M2 and TTY are used. The angular and momentum dependence of the fully off-shell transiti…
The momentum distribution is a powerful probe of strongly-interacting systems that are expected to display universal behavior. This is contained in the contact parameters which relate few- and many-body properties. Here we consider a Bose gas in two dimensions and explicitly show that the two-body contact parameter is universal and then demonstrate that the momentum distribution at next-to-leading order has a logarithmic dependence on momentum which is vastly different from the three-dimensional case. Based on this, we propose a scheme for measuring the effective dimensionality of a quantum ma…
In a recent work \cite{Anderson:2010aq}, Anderson \emph{et al.} used the renormalization group (RG) evolution of the momentum distribution to show that, under appropriate conditions, operator expectation values exhibit factorization in the two-nucleon system. Factorization is useful because it provides a clean separation of long- and short-distance physics, and suggests a possible interpretation of the universal high-momentum dependence and scaling behavior found in nuclear momentum distributions. In the present work, we use simple decoupling and scale-separation arguments to extend the result…
We present an overview of low-momentum two-nucleon and many-body interactions and their use in calculations of nuclei and infinite matter. The softening of phenomenological and effective field theory (EFT) potentials by renormalization group (RG) transformations that decouple low and high momenta leads to greatly enhanced convergence in few- and many-body systems while maintaining a decreasing hierarchy of many-body forces. This review surveys the RG-based technology and results, discusses the connections to chiral EFT, and clarifies various misconceptions.
