Speaker
Description
Atomic systems offer a plethora of fundamental and functional properties and therefore are of importance to several key implications. Some examples where atoms and ions can serve as important probes include, atomic clocks [1], parity and time-reversal violations [2, 3], and the search for the variations in the fundamental constants [4]. Atomic systems, however, form a many-body complex system for which the exact solution is nontrivial. This poses a serious challenge in the theoretical investigations of the properties of these systems. In this context, relativistic coupled-cluster (RCC) theory is one of the most reliable many-body theories for structure and properties calculations for atoms and ions.
In our group at IIT Delhi, we have developed RCC based theories for the properties calculations of closed-shell [5], one-valence [6, 7] and two-valence [8, 9] atomic systems. These theories are implemented as sophisticated parallel FORTRAN programs [10]. The methods and codes we have developed are robust and can compute a plethora of properties, such as excitation energies, transition
amplitudes and oscillator strengths, hyperfine splitting constants and energies, dipole polarizabilities, parity and time-reversal violating amplitudes, etc., in different types of atoms and ions. Our calculations also incorporate the corrections from relativistic and QED effects to improve the accuracies of results.
In this talk, I shall present our recent studies of highly charged ions (HCIs). We study the clock transition related properties for HCIs as optical atomic clock candidates and assess their sensitivity to probe the variation in the fine structure constant. In addition, we also examine the prospects of HCIs for exploring parity non-conservation (PNC) effects. HCIs are considered to be promising candidate for these applications due to their relatively simpler structures and their strong immunity to the environmental perturbations. To investigate their sensitivity to the variation of fine structure constant, we have studied three systems, Cf17+, Cm15+ and Bk16+ , and found that these ions exhibit exceptionally large sensitivity coefficients compared to existing optical clock candidates. Further, we have explored PNC effects in Li like HCIs and observed a significant enhancement arising from the strong overlap of electronic wavefunctions with the nucleus. These results show that HCIs are promising systems for precision measurements and tests of fundamental symmetries.
[1] Andrew D. Ludlow, Martin M. Boyd, and Jun Ye, Rev. Mod. Phys. 87, 637 (2015).
[2] C. S. Wood et al., Science 275, 1759 (1997).
[3] W. C. Griffith, et al., Phys. Rev. Lett. 102, 101601 (2009).
[4] S. G. Karshenboim and E. Peik, Astrophysics, Clocks and Fundamental Constants, Lecture Notes in Physics (Springer, New York, 2010).
[5] Ravi Kumar, S. Chattopadhyay, D. Angom, and B. K. Mani, Phys. Rev. A 101, 012503 (2020)
[6] Ravi Kumar, D. Angom, and B. K. Mani, Phys. Rev. A. 106, 032801 (2022).
[7] Suraj Pandey, Ravi Kumar, D. Angom, and B. K. Mani, Phys. Rev. A 112, 032811 (2025).
[8] Ravi Kumar, S. Chattopadhyay, D. Angom, and B. K. Mani, Phys. Rev. A. 103, 022801 (2021).
[9] Palki Gakkhar, Ravi Kumar, D. Angom, and B. K. Mani, Phys. Rev. A 110, 013119 (2024)
[10] B. K. Mani, S. Chattopadhyay, and D. Angom, Comp. Phys. Comm. 213, 136 (2017).