Classification of three-photon states in waveguide QED | Janet Zhong

Theoretical Seminar at The Department of Physics & Engineering, ITMO | 10 Feb 2021

Miss Janet Zhong,
The Australian National University, Stanford University

Title: "Classification of three-photon states in waveguide quantum electrodynamics"

Abstract:
We provide the first classification of three-photon eigenstates in a finite periodic array of two-level atoms coupled to a waveguide. We focus on the strongly subwavelength limit and show the hierarchical structure of the eigenstates in the complex plane. The main characteristic eigenstates are explored using entanglement entropy as a distinguishing feature. We show that the rich interplay of effects from order, chaos to localisation found in two-photon systems extends naturally to three-photon systems. There also exist interaction-induced localised states unique to three-photon systems such as bound trimers, corner states and trimer edge states.

Literature:

0:00 Intro
1:05 Start of the talk

Part 1: What is Waveguide QED
2:08 Motivation - why do care about waveguide QED
3:15 Waveguide QED setup
3:41 Why is waveguide QED interesting
5:10 Literature reference(waveguide QED)
5:23 Experimental setup
6:45 The way to describe waveguide QED systems (hamiltonian)
7:12 Effective non-Hermitian hamiltonian for waveguide QED
8:14 Question by Maxim Gorlach
9:05 Comment by Alexander Poddubny
10:15 Polarations in a waveguide
11:24 Single-photon eigenstates
11:48 Part summary

Part 2: Two-photon states
12:18 main types of two-photon eigenstates
13:48 Scattering states
14:41 Fermionic state
15:47 Interaction-induced localization
17:37 Other types of localization and reference
18:11 Chaotic states
18:48 Question by Mihail Petrov
21:14 Comment by Alexander Poddubny
23:04 Question by Maxim Gorlach
25:39 Bound dimer
26:15 Topological edge states
27:26 Hofstadter-like butterfly
27:52 Part summary

Part 3: Three-photon states
28:23 Main types of three-photon eigenstates
28:53 Entanglement entropy
29:26 Question by Ivan Iorsh
31:04 Question by Maxim Gorlach
32:41 Scattering state
33:17 Fermionic states
33:37 Chaotic states
33:49 Localization
35:39 Question by Maxim Gorlach
36:38 Question by Mihail Petrov
39:09 The search for a trimer
40:20 Trimer edge states
41:35 Corner states
42:22 Question by Maxim
43:16 Asymmetrical localization states
43:36 Part summary

44:02 Summary
44:40 Question by Maxim Gorlach
45:56 Question by Ivan Yorsh
48:38 Question by Mihail Petrov
55:45 Questions by Yuri Marques

The Department of Physics and Engineering of ITMO University (Saint Petersburg, Russia) hosts online weekly seminars to discuss recent scientific achievements of researchers from all over the world with a wide audience. The topics include experimental (Optical seminar) and theoretical (Theoretical seminar) aspects of nanophotonics, solid-state physics, material science, as well as design and applications of radiofrequency structures and devices (Microwave seminar).

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