Title:

"Applications of exceptional points in open quantum and optical systems"

 

Abstract:

An exceptional point (EP) is a unique type of modal degeneracy that can occur in open systems and can lead to many intriguing phenomena. In the first part of the talk, I will discuss three phenomena that arise due to special features in the density of states near EPs. Specifically, I will show 1. How to use degenerate optical resonators with EPs to achieve dramatic enhancement of spontaneous emission from quantum emitters, potentially surpassing the traditional Purcell factor [1-2]. 2. How to create laser driven EPs in atoms and molecules and use those to control photoionization, enabling either enhancement or complete suppression under appropriate conditions [3]. 3. How similar principles can be used to shape the relative amplitude and phase of high harmonics produced by strong laser pulses that interact with atoms and molecules with autoionization resonances. 

 

In the second part of this talk, I will explain how degeneracy and symmetry can be used to find noise-resilient control protocols in noisy environments. I will show two applications of this principle to quantum information processing: 1. A protocol for robust mode conversion in NV centers, which relies on adiabatic encircling of an EP in the control parameters’ space [4]. 2. A rapid yet robust protocol for transition between non-radiating atomic states, that we call “stimulated Raman inertial passage (STIRIP)”. The protocol is similar in spirit to stimulated Raman adiabatic passage (STIRAP), but with the adiabatic condition relaxed, since we move to another frame of reference and find protocols that are adiabatic in that frame (following a recent proposal by Dann and Kosloff [5]). I will conclude by presenting a future extension of these ideas for controlling single photons, which can find uses in photonic quantum computation. 

 

[1] A Pick et Al., Opt. Express, 25 (11), 12325 (2017)

[2] Z Lin, A Pick, et Al., Phys. Rev. Lett. 117 (10), 107402 (2016)

[3] A Pick et Al., J. Phys. Chem., 150, 204111 (2019)

[4] A Pick et Al., Phys. Rev. Research 1, 013015 (2019)

[5] R. Dann and R. Kosloff, Phys. Rev. Research 3, 013064 (2021)