# New article: Quantum Algorithm for Simulating the Wave Equation

**Posted:**November 16, 2017

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Quantum Information Group @ CBPF

Title: Quantum Algorithm for Simulating the Wave Equation

Authors: Pedro C.S. Costa (CBPF), Stephen Jordan (NIST/Maryland), Aaron Ostrander (Maryland)

Link: https://scirate.com/arxiv/1711.05394

Abstract: We present a quantum algorithm for simulating the wave equation under Dirichlet and Neumann boundary conditions. The algorithm uses Hamiltonian simulation and quantum linear system algorithms as subroutines. It relies on factorizations of discretized Laplacian operators to allow for improved scaling in truncation errors and improved scaling for state preparation relative to general purpose linear differential equation algorithms. We also consider using Hamiltonian simulation for Klein-Gordon equations and Maxwell’s equations.

# New article: Reversing the thermodynamic arrow of time using quantum correlations

**Posted:**November 14, 2017

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Quantum Information Group @ CBPF

Title: Reversing the thermodynamic arrow of time using quantum correlations

Authors: Kaonan Micadei, John P. S. Peterson, Alexandre M. Souza, Roberto S. Sarthour, Ivan S. Oliveira, Gabriel T. Landi, Tiago B. Batalhão, Roberto M. Serra, Eric Lutz

Link: https://arxiv.org/abs/1711.03323

Abstract: The second law permits the prediction of the direction of natural processes, thus defining a thermodynamic arrow of time. However, standard thermodynamics presupposes the absence of initial correlations between interacting systems. We here experimentally demonstrate the reversal of the arrow of time for two initially quantum correlated spins-1/2, prepared in local thermal states at different temperatures, employing a Nuclear Magnetic Resonance setup. We observe a spontaneous heat flow from the cold to the hot system. This process is enabled by a trade off between correlations and entropy that we quantify with information-theoretical quantities.

# QM Talks@CBPF: Alexandre B. Tacla — 13.11, 16h00

**Posted:**November 11, 2017

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Quantum Information Group @ CBPF

Our next talk in the series QM Talks@CBPF will be delivered by Alexandre B. Tacla (Glasgow). Alexandre has many interests, and a broad knowledge. In this talk he will tell us about his recent results on how to deal with complex many-body systems in an efficient way.

Note that this week, due to the holiday celebrating the Proclamation of the Republic in Brazil on Wednesday, the talk will be on Monday. See the full info below, and be sure to not miss this talk!

Title: Particle-correlated states: A non-perturbative treatment beyond mean field

Speaker: Alexandre B. Tacla (Glasgow)

Coordinates: room 601C, CBPF. 13.11 (**Monday**), 16h00

Abstract: Many useful properties of dilute Bose gases at ultralow temperatures are predicted precisely by the (mean-field) product-state Ansatz, in which all particles are in the same single-particle state. However, in situations where particle-particle correlations become important, this technique fails and more sophisticated…

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# Talk @UFF, Márcio Taddei (UFRJ), Friday Nov. 10th, 11.00

**Posted:**November 7, 2017

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Next Friday, Nov. 10th at 11.00 in room A5-01 we’ll have our next group seminar at UFF. This time Márcio Taddei (UFRJ) will be talking on “Superposição quântica de ordens causais”. All are welcome! for an abstract please see below. Read the rest of this entry »

# Postdoctoral position in Quantum Information Theory at ICTP/SAIFR São Paulo

**Posted:**November 6, 2017

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Dear colleagues,

I would like to draw your attention to a postdoctoral position in the fields of quantum computing, quantum information theory, and foundations of quantum mechanics.

The postdoc will work with Prof. Leandro Aolita, who will be a regular visiting fellow at the International Centre for Theoretical Physics – South American Institute for Fundamental Research (ICTP/SAIFR), in São Paulo, Brazil,

The centre — created in 2011 as a collaboration of ICTP (Trieste), the São Paulo State University (UNESP), and the São Paulo Research Funding Agency — has rapidly positioned itself as a South American hub for theoretical physics. It is located in the vibrant city of São Paulo and has a large number of postdocs and visitors, with an effervescent scientific agenda throughout the year. For further information about the centre see:

The postdoctoral fellowship will be for 2 years, with a possible extension for another 2 years, and will pay an annual tax-free salary of 86,000 Brazilian reais (about US$ 2,200 monthly) as well as a yearly allowance of 12,900 Brazilian reais (about US$ 3950) for travelling and research expenses. In addition to that, other funds may be available too, and ICTP/SAIFR postdocs also have access to ICTP-SAIFR funds to invite visitors and organize activities.

Successful candidates should demonstrate a world-class academic track in the above-mentioned fields and a high level of scientific independence. Background in quantum algorithms and machine learning is specially welcome.

The position should be filled during the first semester of 2018. Applications are expected before December 15th 2017, and should be sent through the online application form at

http://www.ictp-saifr.org/?page_id=625

Best regards,

Leandro Aolita

# QM Talks@CBPF: Marcelo F. Santos — 08.11, 16h00

**Posted:**November 6, 2017

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Quantum Information Group @ CBPF

This week we have the pleasure to receive Marcelo F. Santos (UFRJ) as a speaker in our series QM Talks@CBPF. Marcelo and co-authors have recently put in the arXiv an intriguing paper: Photonic Counterparts of Cooper Pairs. This article, already accepted for publication in Physical Review Letters, attracted quite some attention (see here the Nature News feature on the article) for proposing that photons can interact inside a medium in a way very similar to that of electrons in a superconducting material, forming the so-called Cooper pairs. Got interested?! Then do not miss Marcelo’s talk. The info follows:

Title: Photonic Cooper pairs

Speaker: Marcelo F. Santos (UFRJ)

Coordinates: room 601C, CBPF. 08.11, 16h00

Abstract: Photons are the elementary particles of light. Contrary to most particles, photons do not interact directly with each other in vacuum. However, when propagating in a material, e.g. water, photon pairs may interact through the medium…

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# Talk @UFRJ, Marcelo Terra Cunha, Monday 06/11, 15H30

**Posted:**November 1, 2017

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

See the *details* of the talk below:

MONDAY, **November 6th**, at **15H30**

in room **343** (3rd floor of block A of the Technology Center building)

**“Is quantum theory just about exclusivity?”**

**Marcelo Terra Cunha (UNICAMP)**

*Abstract:*

Quantum Theory is a very successful set of rules about calculating probabilities of measurement outcomes. But what is it really about? This naive question is still open… Probably, the most basic non-classical feature of quantum theory is contextuality: the failure of conciliating the probabilities prescribed by quantum theory with averaging over models with definite answers for any question. In this talk we must review the notion of contextuality and its exclusivity-graph approach, introduced by Cabello, Severini, and Winter. Then we will elaborate on the question: can the exclusivity principle generate the same set of correlations of quantum theory?

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You can incorporate our calendar to your *Google Calendar* and have information about all the confirmed seminars using this link.

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