QM Talks@CBPF: Leandro Aolita 04/04, 16h00

Título: Como confiar nas tecnologias quânticas de muitos corpos?

Palestrante: Mario Leandro Aolita (UFRJ)

Coordenadas: sala 601C, CBPF. 04/04, 16h00

Resumo: Recentemente houve um progresso experimental impressionante em tecnologias quânticas de muitos corpos. No entanto, ainda não temos ferramentas práticas de certificação que nos permitam garantir se os dispositivos quânticos experimentais que construímos funcionam adequadamente. De fato, uma vez que a simulação clássica de sistemas quânticos é uma tarefa computacionalmente difícil — exponencial no número de partículas — o paradigma usual de “predizer e comparar com o experimento” torna-se inaplicável. Este é um dos maiores obstáculos para as tecnologias quânticas de grande escala. Neste seminário, falarei sobre avanços recentes na validação de computadores quânticos e simuladores quânticos de muitos corpos. Em particular, discutirei testemunhas de fidelidade para simulações quânticas de bosons e para cadeias de spins, computação quântica verificável e tomografia de estado quântico assistida por redes neurais nativas de aprendizado de máquina sem supervisão.

Advertisements

VII Paraty Quantum Information School and Workshop: Registration is now open

quantum Rio

PARATY2019_poster

Dear colleague,

We would like to announce the “VII Paraty Quantum Information School and Workshop” (http://2019.paratyquantum.info/) that will take place in Paraty, Brazil from August 05 to 16, 2019.

We would be grateful if you could spread the word and bring the event to the attention of your group and to anyone else that might be interested. Click on the above picture to get the poster!

As in previous editions, the idea is to merge high level scientific exchange and a very pleasant atmosphere. The event will be held at the idyllic setting of Paraty, on Rio de Janeiro’s Costa Verde. The school runs from 5 to 9 August while the workshop takes place between 12 and 16 August 2019.

Come and be part of this story!

Courses of the school:

Quantum-assisted machine learning in near-term quantum devices
Alejandro Perdomo-Ortiz (University College London)

Entangled Structures in Classical and…

View original post 88 more words

New article: Spin-entanglement wave in a coarse-grained optical lattice



Title: Spin-entanglement wave in a coarse-grained optical lattice

Authors: Pedro Silva Correia, Fernando de Melo

Link: https://arxiv.org/abs/1902.08574

Abstract: In the present work we explore a suitable coarse graining channel as a tool to describe entanglement spreading in a coarse-grained spin-chain with different degrees of resolution. Comparing with the experimental realizations performed with ultracold atoms, our results suggest that even if we are not able to fully resolve the system, entanglement can still be detected for some coarse graining levels. Furthermore, we show that it is possible to have some information about the “microscopic” entanglement, even if we have access only to the system’s coarse graining description. We show that the amount of entanglement decays exponentially with the lack of system resolution. The lack of experimental resolution might thus lead to a classical effective description.

QM Talks@CBPF: Alexis Hernández — 06/12, 16h00

The year is about to finish… but we continue full power. This week our series of seminars QM Talks@CBPF, have the pleasure to welcome Alexis Hernández, from the Federal University of Rio de Janeiro. Alexis has many interests within physics (and outside of it as well!). This time he’ll tell us about a nonlinear description of Hall voltages. See details below.

Title: Investigating transverse Hall voltages using two-terminal setups

Speaker: Alexis Hernández (UFRJ)

Coordinates: room 601C, CBPF. 06/12, 16h00

Abstract: In this talk, we present a method to numerically study transverse Hall voltages using an alternative quantity in two-terminal setups. Using nonlinear transport concepts, we find that the Hall voltage dependence on the model parameters can be investigated from the difference between the injectivities of each terminal. The method is suitable to work with nonequilibrium Green’s functions as well as for scattering matrix approaches. We illustrate the proposed idea by studying the quantum spin Hall effect in graphene with disordered spin-orbit scattering centers induced by adatoms. We use two distinct models: a finite-difference implementation of the Dirac Hamiltonian and a tight-binding Hamiltonian combined with the scattering matrix approach and the nonequilibrium Green’s functions approach, respectively.

III Quantum Rio Workshop

quantum Rio

Despite of all difficulties of the present, and uncertainties of the future, it is time to gather the quantum info community/family from Rio. The quantum Rio Workshop, now in its third edition, will take place at CBPF from the 5th to the 6th of November. See the tentative schedule below. More information at https://quantumrio.wordpress.com/iii-quantum-rio-workshop/

We hope to see all the family there!

Coordinates: Auditorium 6th floor, CBPF.

Dates: 05/11 and 06/11

Program:

Monday (05/11)Tuesday (06/11)
10h00 — 10h30Welcome CoffeeWelcome Coffee
10h30 — 11h00 José Augusto Fernando Nicácio
11h00 — 11h30Frederico B. BritoReinaldo Faria
11h30 — 12h00Alexandre MartinsThiago Guerreiro
12h00 — 14h00LunchLunch
14h00 — 14h30Ranieri NeryErnesto Galvão
14h30 — 15h00Carlos EduardoAlfredo Ozorio
15h00 — 16h00coffee-break + postercoffee-break + poster
16h00h — 16h30Stephen WalbornEduardo Duzzioni
16h30h — 17h00Fernando de MeloAntônio Zelaquett

View original post

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

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 some current experimental results with polystyrene microspheres immersed in water at distances below 500nm by employing very soft optical tweezers, with stiffness in the scale of fN/nm. Finally, we also described some theoretical results and future perspectives to suppress the electrostatic double-layer force always present in this context, and some theoretical results concerning light reverberation between the microspheres. This line of investigation has the potential for bringing together different fields including classical and quantum optics, statistical physics and colloidal science, while paving the way for novel quantitative applications of optical tweezers in cell and molecular biology.

References:

D. S. Ether, L. B. Pires et al, EPL 112, 44001 (2015).
D. S. Ether, F. S. S. Rosa et al, PRE 97, 022611 (2018).

4a Escola Avançada de Física Experimental do CBPF

Estão abertas as inscrições para 4a Escola Avançada de Física Experimental (EAFExp) do CBPF!

Nesta escola estudantes de graduação e de pós-graduação têm a oportunidade de entrar em contato com os pesquisadores do CBPF e suas linhas de pesquisa, além de entrarem em contato com diversas técnicas experimentais em diferentes áreas da Física.

Na EAFExp os alunos são separados em pequenos grupos e cada grupo é inserido em apenas um módulo (curso) da escola. Assim, os estudantes têm a oportunidade de conhecer a fundo como são as atividades de pesquisa de um físico experimental. Esta característica faz desta uma escola especial onde os estudantes selecionados passam duas semanas realizando atividades de pesquisa que incluem o planejamento dos estudos experimentais a serem realizados, realização dos experimentos em equipamentos de última geração, análise de dados e apresentação de seminários relatando seus resultados para professores e outros estudantes da própria escola.

A 4a EAFExp ocorrerá entre 4 e 15 de fevereiro de 2019. As inscrições se encerram no dia 15 de novembro de 2018.

Contato: eafexp@cpbf.br

Home page: www.cbpf.br/eafexp/