Talk @UFRJ, Márcio Taddei (UFRJ), Monday 18/09, 15H30

The Quantum Optics and Information Group (UFRJ) is proud to announce next week’s seminar, which will be given by Márcio Taddei (UFRJ). We invite all to come!

See the details of the talk below:

MONDAY, September 18th, at 15H30 
in room 343 (3rd floor of block A of the Technology Center building)
Superposição quântica de ordens causais
Márcio Taddei (UFRJ)
Abstract: 

A não-separabilidade causal trata de superposições quânticas de eventos que possuem ordens causais mutuamente excludentes. Um exemplo de tal propriedade seria a superposição de um processo em que um fóton primeiro é enviado a Alice, que o envia a Bob, com outro em que Bob recebe este fóton primeiramente e o envia a Alice — tudo isto havendo um único fóton no processo. Apesar da aparência especulativa, o fenômeno tem realizações simples e o princípio já foi observado experimentalmente com implementação em ótica quântica. Há ainda resultados teóricos que demonstram que eventos causalmente não-separáveis servem de recurso para a realização de tarefas computacionais com vantagem sobre modelos clássicos.

Introduziremos brevemente o formalismo de matrizes de processo, que descreve o ordenamento causal independente da ação específica de cada participante, bem como a representação de Choi-Jamiołkowski, útil para sua interpretação. ​Abordaremos a questão de como tratar a não-separabilidade causal como um recurso, quais são as transformações incapazes de gerar este recurso e como ele pode ser manipulado. Estudamos fenômenos interessantes como a transferência de coerência de um qubit a um processo inteiro, as dificuldades de lidar com mais de uma cópia de uma matriz de processo e, por fim, a destilação de não-separabilidade causal sem utilizar operações que criem o recurso.

 

You can incorporate our calendar to your Google Calendar and have information about all the confirmed seminars using the following link:

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Talk @UFF, Enrique Arias (UERJ), Friday Sept. 15th, 11.00

Next Friday, Sept. 15th, at 11:00 in room A5-01, we’ll have our next group seminar at UFF. Enrique Arias (UERJ) will be talking on “Motor térmico quântico de Otto via o efeito Unruh”. All are welcome! For an abstract please see below. Read the rest of this entry »


Talk @UFRJ, Lucas Celeri (UFG), Monday 11/09, 15H30

The Quantum Optics and Information Group (UFRJ) is proud to announce the new series of seminars that will be held each week at the University. Next week’s seminar will be given by Lucas Celeri (UFG). We invite all to come!

See the details of the talk below:

MONDAY, September 11th, at 15H30 
in room 343 (3rd floor of block A of the Technology Center building)
“The role of quantum coherence in non-equilibrium entropy production”
Lucas Celeri (UFG)
Abstract: 
Thermodynamic irreversibility is well characterized by the entropy production arising from non-equilibrium quantum processes. We show that the entropy production of a quantum system undergoing open-system dynamics can be formally split into a term that only depends on population unbalances, and one that is underpinned by quantum coherences. The population unbalances are found to contribute to both an entropy flux and an entropy production rate. The decoherence, on the other hand, contributes only to the entropy production rate. This allows us to identify a genuine quantum contribution to the entropy production in non-equilibrium quantum processes. We make use of such a division to address the open-system dynamics of a spin J particle, which we describe in phase space through a spin-coherent representation.

 

You can incorporate our calendar to your Google Calendar and have information about all the confirmed seminars using the following link:


Talk @UFF, Michał Oszmaniec, Wednesday Aug. 30th, 11:00

The VI Paraty Quantum Information Workshop is ending today, and next week we’ll take the opportunity to host Michał Oszmaniec (Gdansk) at UFF. Next Wednesday, Aug. 30th, at 11:00 in room A5-01 Michał will be giving a talk titled: “Preparation contextuality in continuous subtheories of quantum mechanics”. All are welcome to attend! For more details, see below. Read the rest of this entry »


Day 4 – VI Paraty Quantum Information Workshop

Today we had the Workshop’s eagerly anticipated boat trip. That didn’t prevent us from having a full morning session, with six talks.

The first talk of the morning was by Dario Gerace (Pavia), and it was on ways to establish long-distance entanglement between quantum dots in solid state systems. Dario started with a review of entanglement measures, some results on entanglement dynamics in open quantum systems, and bath engineering. Then he introduced the main open problem addressed by his talk: how far can two qubits be and still display entanglement in current solid state systems? Read the rest of this entry »


Day 3 – VI Quantum Information Workshop, Paraty

The morning session started with Fernando Brandão (Caltech), who described joint work with K. Svore. He described a series of related quantum algorithms that they developed to solve semi-definite programming problems (SDPs). SDPs are an important class of convex optimization problems, with applications in operations research, bioengineering, approximating NP-hard problems, and field theory. Read the rest of this entry »


Day 2 – VI Paraty Quantum Information Workshop

The morning session started with a talk by Juliette Monsel (Inst. Nèel, Grenoble), on the thermodynamical study of a hybrid optomechanical system. More precisely, she studies the same experimental system described in Pierre-Louis’ talk: a quantum dot at the basis of an oscillating nanowire. They investigate a quarter of an oscillation. While the wire oscillates, the quantum dot does random jumps between ground and excited states. So the trajectory will be a patchwork of the different trajectories associated with different frequencies. In this way, jump history can give information about trajectory. This allows for the estimate of the entropy production. Read the rest of this entry »