arXiv subjects

Bharti Bhoy

Publications and source records attributed to Bharti Bhoy.

7 recordsLinked to original sources

arXiv2024

Shell-model study of $^{58}$Ni using quantum computing algorithm

This study presents a simulated quantum computing approach for the investigation into the shell-model energy levels of $^{58}$Ni through the application of the variational eigensolver (VQE) method in combination with a problem-specific ansatz. The primary objective is to achieve a fully accurate low-lying energy spectrum of $^{58}$Ni. The chosen isotope, $^{58}$Ni is particularly interesting in nuclear physics through its role in astrophysical reactions while also being a simple but not-trivial nucleus for shell-model study, it being two particles outside a closed shell. Our ansatz, along with the VQE method are shown to be able to reproduce exact energy values for the ground state and first and second excited states. We compare a classical shell model code, the values obtained by diagonalization of the Hamiltonian after qubit mapping, and a noiseless simulated ansatz+VQE simulation. The exact agreement between classical and qubit-mapped diagonalisation shows the correctness of our method, and the high accuracy of the simulation means that the ansatz is suitable to allow a full reconstruction of the full nuclear wave function.

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arXiv2023

Shell-model study for $^{204-210}$Tl isotopes and core excitations across the $Z = 82$ and $N = 126$ shell gaps

In the present work, the $^{204-210}$Tl isotopes have been investigated by performing large-scale shell-model calculations, including configurations allowing both neutron and proton core excitations across the $Z$ = 82 and $N$ = 126 shell gaps. Inspired by the recent high-spin experimental data, the structure of Tl isotopes has been studied for a considerably large model space. The KHHE interaction has been used for $^{204-206}$Tl isotopes, KHH7B interaction for $^{204-210}$Tl isotopes, and additionally KHM3Y interaction has been used for $^{208}$Tl isotope. The core excitation has been performed using the KHH7B and KHM3Y interactions. The level spectra of $^{204-210}$Tl isotopes are comprehensively described and explained by multi-nucleon couplings of single-particle-hole orbitals within the valence space and by core excitations across $^{208}$Pb core. The well-known isomeric states are analyzed in terms of the shell model configurations.

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arXiv2022

Systematic shell model study for $N=82$ and $N=126$ isotones and nuclear isomers

In the present work, we have done a systematic shell model study of $N=82$ and $N=126$ isotones. For the $N=82$ isotones, we have performed calculations using SN100PN interaction, while for $N=126$ isotones, we have used KHPE interaction. Similarities between these two isotonic chains have been reported, using the strong resemblance between the high-$j$ orbitals. Apart from the nuclear spectroscopic properties, we have also explained different isomeric states in these two regions. In the $N$ =82 region, we have mainly discussed the properties of the $6^+$ and $17/2^+$ isomers, while in the $N=126$ region for $8^+$, $11^-$, $21/2^-$ and $29/2^+$ isomers. We have reported $B(E2)$, $B(E3)$, $g$-factor, and quadrupole moments of the isomeric states for comparison in these two isotonic chains.

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arXiv2021

Systematic shell-model study of Rn isotopes with $A=$ 207 to 216 and isomeric states

We present systematic large-scale shell-model calculations for Rn isotopes with $A=$ 207 to 216. For the $^{207-212}$Rn isotopes, we perform calculations with KHH7B interaction, while for $^{213-216}$Rn isotopes with KHPE and KHH7B interactions. The calculated energies and electromagnetic properties are compared with the available experimental data and predicted where experimental data are not available. We also suggest spins and parities of several unconfirmed states available from the recent experimental data. Comprehensive study of several isomeric states from the calculated shell-model configurations and half-lives is also reported.

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arXiv2021

Isomers in 203Tl and core excitations built on a five-nucleon-hole structure

Isomers with three- and five-nucleon-hole configurations have been established in $^{203}$Tl. These include newly identified levels with a three-nucleon structure: {\it I}$^{π}$ = (15/2$^{-}$) with {\it T}$_{1/2}$ = 7.9(5) ns, and {\it I}$^{π}$ = (35/2$^{-}$) with {\it T}$_{1/2}$ = 4.0(5) ns. In addition, five-quasiparticle states: {\it I}$^{π}$ = (39/2$^{-}$) with {\it T}$_{1/2}$ = 1.9(2) ns, and {\it I}$^{π}$ = (49/2$^{+}$) with {\it T}$_{1/2}$ = 3.4(4) ns have also been established. The previously determined long-lived decay [{\it T}$_{1/2}$ = 6.6(3) $μ$s from this work] is associated with isomerism of the {\it I}$^{π}$ = (29/2$^{+}$) state. Levels above this long-lived isomer have been identified through a delayed-prompt coincidence measurement. Five-nucleon-hole states with excitation energies {\it E}$_{x}$ $\approx $ 7 MeV have been established as well as possible octupole excitations of the $^{208}$Pb core built on these levels. The level scheme of $^{203}$Tl is extended up to {\it E}$_{x}$ $\approx $ 11 MeV with the inclusion of 25 new transitions. Empirical and shell-model calculations have been performed to aid in the description of the observed states which are found to be predominantly of intrinsic character.

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arXiv2020

Shell model results for $^{47-58}$Ca isotopes in the $fp$, $fpg_{9/2}$ and $fpg_{9/2}d_{5/2}$ model spaces

We have reported shell-model results for $^{47-58}$Ca isotopes in the $fp$, $fpg_{9/2}$ and $fpg_{9/2}d_{5/2}$ model spaces using realistic $NN$ interaction. We have also performed a systematic shell-model study using interactions derived from in-medium similarity-renormalization group (IM-SRG) targeted for a particular nucleus with chiral $NN$ and $3N$ forces. The results obtained are in a reasonable agreement with the available experimental data in $fp$ model space with $NN$ interaction. It is shown that the $g_{9/2}$ and $d_{5/2}$ orbitals play an important role for heavier neutron-rich $^{54-58}$Ca isotopes, while it is marginal for $^{47-52}$Ca. We have also examined spectroscopic factor strengths using $NN$ and $NN+3N$ interactions for recently available experimental data.

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arXiv2019

Different seniority states of $^{119-126}$Sn isotopes: shell model description

In the present work available experimental data up to high-spin states of $^{119-126}$Sn isotopes with different seniority ($v$), including $v$ = 4, 5, 6, and 7 have been interpreted with shell model, by performing full-fledged shell model calculations in the 50-82 valence shell composed of $1g_{7/2}$, $2d_{5/2}$, $1h_{11/2}$, $3s_{1/2}$, and $2d_{3/2}$ orbitals. The results have been compared with the available experimental data. These states are described in terms of broken neutron pairs occupying the $h_{11/2}$ orbital. Possible configurations of seniority isomers in these nuclei are discussed. The breaking of three neutron pairs have been responsible for generating high-spin states. The isomeric states $5^-$, $7^-$, $10^+$ and $15^-$ of even Sn isotopes, and isomeric states $19/2^+$, $23/2^+$, $27/2^-$ and $35/2^+$ of odd Sn isotopes, are described in terms of different seniority. For even-Sn isotopes, the isomeric states $5^-$, $7^-$, and $10^+$ are due to seniority $v$ = 2; the isomeric state $15^-$ is due to seniority $v$ = 4, and in the case of odd-Sn isotopes, the isomeric states $19/2^+$, $23/2^+$, and $27/2^-$ are due to seniority $v$ = 3, and the isomeric state $35/2^+$ in $^{123}$Sn is due to seniority $v$ = 5. These are maximally-aligned spin, which involve successive pair breakings in the $ν(h_{11/2})$ orbit.

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