Theses
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2018-01-23
NOSLEN SUAREZ
2018-02-26
BENJAMIN WOLTER
2018-03-23
QUAN LIU
2018-03-28
LARA LAPARRA
2018-05-22
KEVIN SCHÄDLER
2018-06-14
MIRIAM MARCHENA
2018-06-19
CARLOS ABELLAN
2018-07-02
LUKAS NEUMEIER
2018-07-24
SHAHRZAD PARSA
2018-07-25
PAU FARRERA
2018-07-31
BARBARA BUADES
2018-09-06
SIMON COOP
2018-09-13
NICOLAS MARING
2018-09-19
IVAN SUPIC
2018-10-02
ANIELLO LAMPO
2018-10-10
CÉSAR CABRERA
2018-10-11
FLORIAN CURCHOD
2018-10-18
JOSEP CANALS
2018-10-19
ROLAND TERBORG
2018-10-24
MIGUEL MIRELES
2018-10-26
KYRA BORGMAN
2018-11-12
JIL SCHWENDER
2018-12-12
LIJUN MENG
2018-12-17
NICOLÁS MORELL
2018-12-18
JUNXIONG WEI

Simulation and bulk detection of topological phases of matter



MARIA MAFFEI
January 29th, 2019 MARIA MAFFEI Quantum Optics Theory
ICFO-The Institute of Photonic Sciences, SPAIN and Università degli Studi di Napoli, ITALY


Differently from the majority of the other phases of matter, which are characterized by local order parameters, the topological phases are characterized by integer or semi-integer numbers, the topological invariants, which are depending on global properties and robust against impurities or deformations. In the last decade, the study of the topological phases of matter has been developing parallel to the field of quantum simulation. Quantum simulators are fully controllable experimental platforms simulating the dynamics of systems of interest by the use of the mapping between the two Hamiltonians. These simulators represent a key resource in the study of topological phases of matter because their observation in natural systems is usually highly problematic and sometimes impossible. Quantum simulators are commonly realized with cold atoms in optical lattices or with photonic systems. The unitary and time-periodic protocols, known as quantum walks, are a versatile class of photonic quantum simulators. The purpose of this PhD thesis is to design feasible protocols to simulate and characterize topological non-interacting crystalline Hamiltonians in 1 and 2 dimensions. Moreover, this thesis contains the description of the experiments that have been completed using the theoretical proposals. In details: i) We demonstrate that the topological invariant associated to chiral symmetric 1D Hamiltonians becomes apparent through the long time limit of a bulk observable, the mean chiral displacement (MCD). This detection method converges rapidly and requires no additional elements (i.e. external fields) or filled bands. The MCD has been used to characterize the topology of a chiral-symmetric 1D photonic quantum walk and to detect a signature of the so-called topological Anderson insulating phase in a disordered chiral symmetric wire simulated with ultracold atoms. ii) We designed the protocol to measure the topological invariant that characterizes a 2D photonic quantum walk simulating a Chern insulator.

Tuesday, January 29. Università degli Studi di Napoli

Thesis Directors: Prof Dr Maciej Lewenstien (ICFO) and Prof. Dr. Lorenzo Marrucci (Università degli Studi di Napoli)