Cátedra (Chaire)  CLAUDE BERNARD – Convênio entre Universidade Federal do Rio de Janeiro, Collège de France, Academias de Ciências Brasileira e Francesa.

 

Dando prosseguimento às atividades da Cátedra Claude Bernard, anunciamos o curso 

STATE ESTIMATION AND RECONSTRUCTION IN QUANTUM INFORMATION  

a ser ministrado por

 

Serge HAROCHE (Professor do Collège de France).

 

Datas: 14, 16, 21 e 23 de março, 04 e 06 de abril 2011.

 

Horário: das 15h às 17h.

 

Local: sala 343, Instituto de Física da UFRJ, Bloco A (terceiro andar), prédio do CT, Ilha do Fundão.

 

Responsável: Prof. Luiz Davidovich ( ldavid@abc.org.br ou ldavid@if.ufrj.br )

 

Claude Bernard Lectures 2011 

STATE ESTIMATION AND RECONSTRUCTION IN QUANTUM INFORMATION 

Serge Haroche, Collège de France & Ecole Normale Supérieure, Paris 
A series of six lectures at UFRJ organized within the exchange program between College de France, the French and Brazilian Academies of Sciences and the Federal University of Rio de Janeiro.
Goal of lectures Manipulating states of simple quantum systems has become an important field in quantum optics and in mesoscopic physics, in the context of quantum information science. Various methods for state preparation, reconstruction and control have been recently demonstrated or proposed. 
Two-level systems (qubits) and quantum harmonic oscillators play an important role in this physics. The qubits are information carriers and the oscillators act as memories or quantum bus linking the qubits together. Coupling qubits to oscillators is the domain of Cavity Quantum Electrodynamics (CQED) and Circuit Quantum Electrodynamics (Circuit-QED). In microwave CQED, the qubits are Rydberg atoms and the oscillator is a mode of a high Q cavity while in Circuit QED, Josephson junctions act as artificial atoms playing the role of qubits and the oscillator is a mode of an LC radiofrequency resonator. The goal of these lectures is to analyse various ways to synthesise non-classical states of qubits or quantum oscillators, to reconstruct these states and to protect them against decoherence. Experiments demonstrating these procedures will be described, with examples from both CQED and Circuit-QED physics. These lectures will give us an opportunity to review basic concepts of measurement theory in quantum physics and their links with classical estimation theory.
Outline of lectures • Lecture 1 (March 14th):  A review of measurement theory, illustrated by the description of a CQED quantum non-demolition (QND) photon counting experiment. • Lecture 2 (March 16th): A review of the quantum Zeno effect: how to use repeated measurements to manipulate non classical states of an oscillator (an experiment proposal). • Lecture 3 (March 21st):  An analyzis of quantum feedback: how to use feedback procedures with QND measurements to drive a quantum system towards a desired state and protect it against decoherence, illustrated by a CQED experiment in progress. • Lecture 4 (March 23rd): An analyzis of state estimation and reconstruction procedures based on ideas imported from classical estimation theory and illustrated by the description of non-classical state reconstructions in CQED. • Lecture 5 (April 4th): An introduction to Circuit-QED presenting in simple terms the physics of Josephson junctions coupled to LC resonators. • Lecture 6 (April 6th):  Description of recent Circuit-QED experiments having synthesized and reconstructed arbitrary states of a field oscillator.