QM Talks@CBPF: Diney Ether — 10/10, 16h00

Quantum Information Group @ CBPF

The 2018 Physics Nobel Prize was awarded “for groundbreaking inventions in the field of laser physics”. Among these inventions are the optical tweezers, which will play an important role in our next QM Talks@CBPF. This week we are pleased to welcome Diney Ether (UFRJ), who is employing optical tweezers to measure very feeble forces due to the Casimir effect. See details below, and be sure to be there!

Title: Perspectives: Probing the Casimir Effect using Optical Tweezers

Speaker: Diney Ether (UFRJ)

Coordinates: room t.b.a, CBPF. 10/10, 16h00

Abstract:
We propose to use optical tweezers to probe the Casimir interaction between microspheres inside a liquid medium. This setup has the potential for revealing unprecedented features associated either with the Casimir force screening by movable ions in solution and the non-trivial role of the spherical curvatures achieved by going beyond the validity of the widely employed proximity force approximation. We will show…

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Talk @UFF, Jacques Pienaar (IIP, Natal), Friday Oct. 5th, 11:00

This week’s talk at UFF will be given next Friday, Oct. 5th, at 11:00 in room A5-01. This time round we’ll have Jacques Pienaar (IIP – Natal) talking on “Causal analysis of Bell inequality violation in classical light”. All are welcome! For an abstract, please see below. Read the rest of this entry »


Talk @UFRJ, Gabriela Lemos, Monday 01/10, 15H30

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

See the details of the talk below:

MONDAY, October 1st, at 15H30
in room 343 (3rd floor of block A of the Technology Center building)

“Sobre a possibilidade de violação de desigualdades de Bell genuínas usando luz “clássica””
Gabriela Lemos (IIP)

Abstract:
Nos últimos vinte anos, as propriedades fascinantes de feixes de luz que exibem “não-separabilidade estrutural” vêm sendo foco de um grande número de pesquisas. A validade e as limitações de uma analogia entre esses estados da luz “clássica” e estados quânticos emaranhados têm sido assuntos amplamente discutidos em publicações e conferências. Em particular, há experimentos mostrando que esses feixes de luz clássica podem violar desigualdades análogas às desigualdades de Bell, nas quais probabilidades de eventos são substituídas por intensidades de luz. Tomando como base um experimento realizado na UFF pelo grupo liderado por Prof. Zelaquette Koury (UFF), um dos pioneiros no assunto, analisamos a possibilidade de violação de desigualdades de Bell genuínas (que se referem a probabilidades de eventos). Vou fazer neste seminário uma revisão de “não-separabilidade estrutual” em feizes de luz clássico, uma revisão de desigualdades de Bell, e apresentar nossos resultados e conclusões.
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You can incorporate our calendar to your Google Calendar and have information about all the confirmed seminars using this link.


Talk @UFF, Daniel Tasca (UFF), Friday Sept. 21st, 11:00

Today’s talk at the Infoptics group will be given by Daniel Schneider Tasca (UFF), who’ll be talking about “How fast is a twisted photon”. As usual, the seminar will be at 11:00 in room A5-01. Hope to see you there! For an abstract, please see below. Read the rest of this entry »


Talk @UFRJ, Diogo Soares, Monday 24/09, 15H30

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

See the details of the talk below:

MONDAY, September 24th, at 15H30
in room 343 (3rd floor of block A of the Technology Center building)

“Time, coherence and quantum reference frames”
Diogo Soares (USP)

Abstract:
The Page and Wootters’ mechanism questioned the fundamental nature of time in quantum physics. The mechanism explored the notion that a given physical quantity is always defined and measured relative to a reference frame, in general, not explained in the theoretical description of quantum physical experiments. Recently, the new area of quantum information theory named resource theory of asymmetry deals explicitly with what are the physical conditions for a quantum system to serve as a good reference frame. In this work, we use this machinery in the Page and Wootters’ mechanism by identifying the concept of local time-asymmetry as relative coherence and establishing an operational theory of relative coherence in a composed quantum systems. To do so, the notion of quantum coherence in relation of a quantum reference frame is revisited and a quantifier is proposed in this scenario. Also, this open space to investigate the link of relative coherence and correlations, as proposed by Page and Wootters, under a resource theory approach.
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You can incorporate our calendar to your Google Calendar and have information about all the confirmed seminars using this link.


QM Talks@CBPF: Diogo O. Soares-Pinto — 26.09, 14h00

Quantum Information Group @ CBPF

Title: Time, coherence and quantum reference frames

Speaker: Diogo O. Soares-Pinto (USP-SC)

Coordinates: COEDU meeting room, 6th floor, CBPF. 26.09, 14h00

Abstract: The Page and Wootters’ mechanism questioned the fundamental nature of time in quantum physics. The mechanism explored the notion that a given physical quantity is always defined and measured relative to a reference frame, in general, not explained in the theoretical description of quantum physical experiments. Recently, the new area of quantum information theory named resource theory of asymmetry deals explicitly with what are the physical conditions for a quantum system to serve as a good reference frame. In this work, we use this machinery in the Page and Wootters’ mechanism by identifying the concept of local time-asymmetry as relative coherence and establishing an operational theory of relative coherence in a composed quantum systems. To do so, the notion of quantum coherence in relation of a quantum reference…

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New article: Quantum revival patterns from classical phase-space trajectories

Quantum Information Group @ CBPF

Title: Quantum revival patterns from classical phase-space trajectories

Authors: Gabriel M. Lando, Raúl O. Vallejos, Gert-Ludwig Ingold, Alfredo M. Ozorio de Almeida

Link: https://arxiv.org/abs/1809.04139

Abstract: A general semiclassical method in phase space based on the final-value representation of the Wigner function is discussed that bypasses caustics and the need to search for classical trajectories. We demonstrate its potential by applying the method to the Kerr Hamiltonian. Fractional revivals sensitive to details in the quantum evolution are obtained semiclassically and provide decisive evidence for the validity of the approach far beyond the Ehrenfest time. There is no constraint on the initial state as is shown by reproducing fractional revivals not only for the usual coherent states but also for a shifted weakly excited Fock state.

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