Van der Waals five-body size-energy universality.

A universal relationship between scaled size and scaled energy is explored in five-body self-bound quantum systems. The ground-state binding energy and structure properties are obtained by means of the diffusion Monte Carlo method. We use pure estimators to eliminate any residual bias in the estimation of the cluster size.

Analysis of non-pharmaceutical interventions and their impacts on COVID-19 in Kerala.

In the absence of an effective vaccine or drug therapy, non-pharmaceutical interventions are the only option for control of the outbreak of the coronavirus disease 2019, a pandemic with global implications. Each of the over 200 countries affected has followed its own path in dealing with the crisis, making it difficult to evaluate the effectiveness of measures implemented, either individually, or collectively. In this paper we analyse the case of the south Indian state of Kerala, which received much attention in the international media for its actions in containing the spread of the disease in the early months of the pandemic, but later succumbed to a second wave.

Universality of size-energy ratio in four-body systems.

Universal relationship of scaled size and scaled energy, which was previously established for two- and three-body systems in their ground state, is examined for four-body systems, using Quantum Monte Carlo simulations. We study in detail the halo region, in which systems are extremely weakly bound. Strengthening the interparticle interaction we extend the exploration all the way to classical systems.

Ground-state properties of weakly bound helium-alkali trimers.

Weakly bound triatomic molecules consisting of two helium atoms and one alkali metal atom are studied by means of the diffusion Monte Carlo method. We determined the stability of HeA, HeHeA, and HeA, where A is one of the alkali atoms Li, Na, K, Rb, or Cs. Some of the trimers with He are predicted to be self-bound for the first time, but this is observed to be dependent on the He-A interaction potential model.

Quantum Halo States in Helium Tetramers.

The universality of quantum halo states enables a comparison of systems from different fields of physics, as demonstrated in two- and three-body clusters. In the present work, we studied weakly bound helium tetramers in order to test whether some of these four-body realistic systems qualify as halos. Their ground-state binding energies and structural properties were thoroughly estimated using the diffusion Monte Carlo method with pure estimators.

Universality in molecular halo clusters.

The ground state of weakly bound dimers and trimers with a radius extending well into the classically forbidden region is explored, with the goal to test the predicted universality of quantum halo states. The focus of the study is molecules consisting of T↓, D↓, ^{3}He, ^{4}He, and alkali atoms, where the interaction between particles is much better known than in the case of nuclei, which are traditional examples of quantum halos. The study of realistic systems is supplemented by model calculations in order to analyze how low-energy properties depend on the interaction potential.

Ground state of small mixed helium and spin-polarized tritium clusters: a quantum Monte Carlo study.

We report results for the ground-state energy and structural properties of small (4)He-T↓ clusters consisting of up to four T↓ and eight (4)He atoms. These results have been obtained using very well-known (4)He-(4)He and T↓- T↓ interaction potentials and several models for the (4)He- T↓ interatomic potential. All the calculations have been performed with variational and diffusion Monte Carlo methods.

Thyroid echogenicity: A clue to precise individual dosimetry in radioiodine therapy of hyperthyroidism.

Background: Radioiodine therapy is a frequent option in treatment of patients with hyperthyroidism. Despite efforts to plan the thyroid absorbed dose by accounting for the gland size and radioiodine kinetics, the success of radioiodine therapy remains largely unpredictable. The current methods plan the mean thyroid radiation absorbed dose, assuming that it applies to target tissue - the thyroid follicular cells.