Atomic coherence and quantum synchronization

Date/Time: 5:00pm, Sept 24th, 2020 - (Virtual Seminar)

Speaker: Prof. Saikat Ghosh (the Indian Institute of Technology)

Lately, quantum coherence has emerged as a central concept in identifying the essential resource for quantum technologies. In this talk, I will describe some of our recent work in probing atomic coherences in real time and in developing a phenomenological quantifier of coherence. The quantifier accurately distinguishes between open, closed and incoherent systems, while capturing the precise transition point from EIT to Autler-Townes regime, with increasing field strength in three-level atoms. Furthermore, using the quantifier, we develop a technique to freeze the generated coherence from decay, in a thermal ensemble of room-temperature atoms. In the second half of the talk, I will discuss some of our recent results confirming the first observation of quantum synchronization, where atomic coherences and their interferences play a key role in synchronizing quantum phases of a spin-1 atom to phases of external, classical fields. References: (1) Arif Warsi Laskar, Niharika Singh, Arunabh Mukherjee and Saikat Ghosh New J. Phys. 18, 053022 (2016). (2) Arif Warsi Laskar, Niharika Singh, Pratik Adhikary, Arunabh Mukherjee and Saikat Ghosh Optica 5, 1462 (2018). (3) Arif Warsi Laskar, Pratik Adhikary, Suprodip Mondal, Parag Katiyar, Sai Vinjanampathy and Saikat Ghosh Phys. Rev. Lett. 125, 013601 (2020)