# A lossy atom that does not decay: PT symmetry and coherent dynamics with complex energies

### APA

Joglekar, Y. (2023). A lossy atom that does not decay: PT symmetry and coherent dynamics with complex energies. Perimeter Institute. https://pirsa.org/23020014

### MLA

Joglekar, Yogesh. A lossy atom that does not decay: PT symmetry and coherent dynamics with complex energies. Perimeter Institute, Feb. 14, 2023, https://pirsa.org/23020014

### BibTex

@misc{ pirsa_PIRSA:23020014, doi = {10.48660/23020014}, url = {https://pirsa.org/23020014}, author = {Joglekar, Yogesh}, keywords = {Condensed Matter}, language = {en}, title = {A lossy atom that does not decay: PT symmetry and coherent dynamics with complex energies}, publisher = {Perimeter Institute}, year = {2023}, month = {feb}, note = {PIRSA:23020014 see, \url{https://pirsa.org}} }

Yogesh Joglekar Indiana University

## Abstract

Isolated quantum systems, investigated a century ago, exhibit coherent, unitary dynamics. When such a system is coupled to an environment, the resulting loss of coherence is modeled by completely positive, trace preserving (CPTP) quantum maps for the density matrix. A lossy atom, when it has not decayed, exhibits a coherent dynamics that is in a distinct, new class. Non-Hermitian Hamiltonians with parity-time symmetry govern this class and exhibit exceptional-point (EP) degeneracies with topological features. After a historical introduction to PT symmetry, I will present examples of coherent, quantum dynamics in the static and Floquet regimes for such systems with a superconducting transmon (Nature Phys. 15, 1232 (2019)), ultracold atoms (Nature Comm. 10, 855 (2019)), and integrated quantum photonics (Phys. Rev. Res. 4, 013051 (2022); Nature 557, 660 (2018)) as platforms. These include topological quantum state transfer, entanglement/coherence control, and super-quantum correlations. I will conclude with speculations on applicability of these ideas to quantum matter, particle physics, and strong gravity.

(* with Anthony Laing group, Kater Murch group, Le Luo group, Sourin Das group).

Zoom link: https://pitp.zoom.us/j/92391441075?pwd=QmRYSnYveUZCci9QZFcwUHBFS29QZz09