Quantum Phase Transitions of Open Many-body photonic systems

Interdisciplinary Areas: Micro-, Nano-, and Quantum Engineering
Project Description
Within the last two decades and with the development of new experimental platforms, such as circuit QED, lattices of ultracold atoms, and exciton-polaritons, the new portal of driven-dissipative quantum systems has been opened. There, the interplay between the interaction, the (in)coherent drive, and the dissipation would lead to the emergence of novel critical phenomena in the nonequilibrium steady state of these open quantum systems, the subject of intense studies recently. So far, several theoretical studies have reported the possibility of unique dissipation-stabilized phase transitions in various many-body systems, possibly displaying novel universal properties. However, the impact of quantum fluctuations and the robustness of such phases against them is still an open question and a subject of debate. The importance of quantum fluctuations' role becomes clearer when we recall that the attainable strong interactions in such engineered systems lead to quantum phase transitions typically at small particle numbers and far away from the thermodynamics limit. Among various platforms, bosonic systems on a lattice have been the object of intense studies, motivated by their analogy with the Bose-Hubbard model and the possibility of their experimental realizations using arrays of optical Kerr cavities, i.e. a third-order optical nonlinearity corresponding to two-body interactions.

In this work, we aim to study the quantum phase transitions of a highly multi-modal Kerr cavity subject to a coherent (single-photon) and incoherent (two-photon) drive, ranging from a few photons (deeply quantum range) to many photons (thermodynamic limit). While the coherent drive supports the multi-stability regions in the phase diagram, the incoherent drive may lead to the emergence of Schrödinger’s cat states that resemble interacting spin dynamics hence, a possible scheme for realizing a photonic simulator of quantum spin models. The results of this study have substantial impacts on the quantum phase transitions of drive-dissipative systems and pave the way towards a new generation of photonic quantum many-body simulators.
Start Date
Post Doc Qualifications
The potential candidate is expected to have a PhD in Physics or EE and be familiar with quantum optics and/or condensed matter physics.
1- Prof. Hadiseh Alaeian, halaeian@purdue.edu, Department of Electrical and Computer Engineering, Department of Physics and Astronomy. 
2- Prof. Sabre Kais, kais@purdue.edu, Department of Physics and Astronomy, Department of Chemistry.
1- N. Dogra et al, Science 366, 1496-1499 (2019) 
2- H. Alaeian et al, Phys. Rev. A 99, 053834 (2019)
3- H. Kassler et al, New J. Phys. 22, 085002 (2020)
4- H. Alaeian et al, Phys. Rev. A 103, 013712 (2021)