Origin of three-body resonances

We expose the relation between the properties of the three-body continuum states and their two-body subsystems. These properties refer to their bound and virtual states and resonances, all defined as poles of the S-matrix. For one infinitely heavy core and two non-interacting light particles, the complex energies of the three-body poles are the sum of the two two-body complex pole-energies. These generic relations are modified by center-of-mass effects which alone can produce a Borromean system. We show how the three-body states evolve in ⁶He, ⁶Li, and ⁶Be when the nucleon-nucleon interaction is continuously switched on. The schematic model is able to reproduce the main properties in their spectra. Realistic calculations for these nuclei are shown in detail for comparison. The implications of a core with non-zero spin are investigated and illustrated for ¹⁷Ne ( ¹⁵O + p + p). Dimensionless units allow predictions for systems of different scales.     

Energy distributions from three-body decaying many-body resonances

We compute energy distributions of three particles emerging from decaying many-body resonances. We reproduce the measured energy distributions from decays of two archetypal states chosen as the lowest 0+ and 1+ resonances in 12C populated in beta decays. These states are dominated by sequential, through the 8Be ground state, and direct decays, respectively. These decay mechanisms are reflected in the "dynamic" evolution from small, cluster or shell-model states, to large distances, where the coordinate or momentum space continuum wave functions are accurately computed.     

Accumulation of three-body resonances above two-body thresholds

We calculate resonances in the three-body system with attractive Coulomb potential by solving homogeneous Faddeev-Merkuriev integral equations for complex energies. The equations are solved using the Coulomb-Sturmian separable expansion method. This approach allows us to study the exact behavior of the three-body Coulomb systems near the threshold. A negatively charged positronium ion is used as a test case. In addition to locating all previously known S-wave resonances of the positronium ion, we also find a large number of new resonant states that accumulate just slightly above the two-body thresholds. The pattern of accumulation of resonant states above the two-body thresholds suggests that probably they are infinite in number. We conjecture that this may be a general property of the three-body system with an attractive Coulomb potential.     

Universal fermi gas with two- and three-body resonances

We consider a Fermi gas with two components of different masses, with the s-wave two-body interaction tuned to unitarity. In the range of mass ratio 8.62相似文献   

Borromean Bound States

The Hall-Post inequalities relating N-body to (N − 1)-body energies of quantum bound states are applied to delimit, in the space of coupling constants, the domain of Borromean binding where a composite system is bound while the smaller subsystems are unbound.     

Borromean rings and linkings

For links of 3 components, such as Borromean rings, which escape the detection of Gauss linking, we define and compute combinatorically and explicitly the higher linking. And as in perturbative quantum field theory, this higher linking is presented as a sum of Chern–Simons–Witten configuration space integrals.     

Relativistic Borromean states

In this work,the existence of Borromean states is discussed for bosonic and fermionic cases in both therelativistic and non-relativistic limits from the 3-momentum shell renormalization.With the linear bosonic model,we check the existence of Efimov-like states in the bosonic system.In both limits a geometric series of singularities is found in the 3-boson interaction vertex,while the energy ratio is reduced by around 70%in the relativistic limit because of the anti-particle contribution.Motivated by the quark-diquark model in heavy baryon studies,we have carefully examined the p-wave quark-diquark interaction and found an isolated Borromean pole at finite energy scale.This may indicate a special baryonic state of light quarks in high energy quark matter.In other cases,trivialresults are obtained as expected.In the relativistic limit,for both bosonic and fermionic cases,potential Borromean states are independent of the mass,which means the results would also be valid even in the zero-mass limit.     

Occurrence conditions for two-dimensional Borromean systems

Features of biphoton polarization-frequency ququarts are considered. Their wave functions are defined as functions of both polarization and frequency variables of photons with the symmetry obligatory for two-boson states taken into account. In experiments, biphoton ququarts can display different features in dependence on whether experiments involve purely polarization or (alternatively) polarization-frequency measurements. If in experiments one uses only polarization measurements, the originally pure states of ququarts can be seen as mixed biphoton polarization states. Features of such states are described and discussed in details. Schemes of coincidence measurements for reconstruction of the ququart’s parameters are suggested and described.     

Core-Excitation Three-Cluster Model of Borromean Nuclei

A new model of the core-nucleus and two-neutron system is introduced. The Faddeev equations of the ⁶He-n-n, ⁸He-n-n and ⁹Li-n-n systems for ⁸He, ¹⁰He and ¹¹Li are solved, respectively. The potential of the subsystem in the model has been constructed to make couplings of the ground state and the excited one inside the core-nucleus. Simple rank one separable Yamaguchi-type potentials between the core-nucleus and neutron are employed with the coupling strength determined from the energy levels and width. We solve the Faddeev three-cluster equations to obtain the low-lying energy levels of ⁸He, ¹⁰He and ¹¹Li. In order to understand the nuclear structures we calculate some inner wave functions and probabilities.     

Borromean Triads of Phonons in a Magnet

Doklady Physics - The results of experimental observation of coupled excitations of three pairwise noninteracting phonons, two of which belong to continuous and the third to discrete acoustic...     

The Quadrupole Response of Borromean Bosonic Trimers

The inelastic response of a Borromean trimer composed of three identical bosons is explored. To this end we use the quadrupole approximation as the excitation mechanism of the bosonic system from its ground state. We utilize the hyperspherical-harmonics expansion to solve the Schroedinger equation and the Lorentz integral transform method to calculate the reaction. It is found that the magnitude of the response function and corresponding sum rules increase as a power law when approaching the three-body threshold. It is also found that this increase is governed by unnatural exponents.     

Ideal homoatomic and heteroatomic photonic crystal molecules

A local tuning of the modes of photonic crystal systems both to blue and to red sides of the resonance is implemented by nano-infiltration/evaporation of water and laser micro-oxidation. This technology is used to completely control coupled photonic nanocavities (photonic crystal molecules). Beside the standard condition of zero detuning between identical modes of the two cavities (homoatomic molecule), we are also able to produce coupling between two modes of different polarization and spatial distribution (heteroatomic molecule).     

Few-body cluster models for Borromean halo nuclei

Modern few-body methods for investigating Borromean two-neutron halo nuclei are discussed together with recent experiments. Advances in the studies of ⁶He and ¹¹Li are analyzed. Some new problems created by a large neutron excess and a halo phenomenon are considered.     

Elastic scattering, muon transfer, bound states and resonances in the three-body mesic molecular systems in the reduced adiabatic hyperspherical approach

The uniform method of numerical investigation of bound states and scattering processes 2→ 2 (including resonance states) in the Coulomb three-body (CTB) systems is developed. It is based on the adiabatic hyperspherical approach (AHSA) and includes the numerical realization and applications to the three-body mesic atomic systems. The results of calculations of bound states of these systems (including the local characteristics of the wave functions) and the scattering processes 2→ 2 (including the characteristics of the resonance states) are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Flame chemistry of tetrahydropyran as a model heteroatomic biofuel

The flame chemistry of tetrahydropyran (THP), a cyclic ether, has been examined using vacuum-ultraviolet (VUV)-photoionization molecular-beam mass spectrometry (PI-MBMS) and flame modeling, motivated by the need to understand and predict the combustion of oxygen-containing, biomass-derived fuels. Species identifications and mole-fraction profiles are presented for a fuel-rich (Φ = 1.75), laminar premixed THP–oxygen–argon flame at 2.66 kPa (20.0 Torr). Flame species with up to six heavy atoms have been detected. A detailed reaction set was developed for THP combustion that captures relevant features of the THP flame quite well, allowing analysis of the dominant kinetic pathways for THP combustion. Necessary rate coefficients and transport parameters were calculated or were estimated by analogies with a recent reaction set [Li et al., Combust. Flame 158 (2011) 2077–2089], and necessary thermochemical properties were computed using the CBS-QB3 method. Our results show that under the low-pressure conditions, THP destruction is dominated by H-abstraction, and the three resulting THP-yl radicals decompose primarily by β-scissions to two- and four-heavy-atom species that are generally destroyed by β-scission, abstraction, or oxidation.     

Borromean Windows for Three-Particle Systems under Screened Coulomb Interactions

We have carried out calculations to search Borromean windows(BWs) for 11 different three-body systems interacting with screened Coulomb(Yukawa-type) potentials using Hylleraas-type wave functions within the framework of a variational approach. The critical values of the screening parameters for the ground states of the systems under consideration are reported for which the three-body systems are stable, while all the possible fragments are unbound;that is, it shows windows for Borromean binding.