Building and Testing Qubits
Monday, 11:30 AM to 12:00 PM
The talk will cover the fundamental principles and challenges involved in designing, fabricating, and characterizing qubits. Topics will include device design, microfabrication techniques, low-temperature measurements, and quantum coherence analysis. The goal is to provide an overview of the practical and theoretical steps required to develop superconducting qubits.
Alexandre de Souza
Brazilian Center for Physical Research
Holds a degree in Physics from the Federal Fluminense University (2000), a master's (2003) and a doctorate (2008) from the Brazilian Center for Physical Research (CBPF). He completed postdoctoral fellowships at Technische Universität Dortmund (Germany) and at the Institute for Quantum Computing (IQC), University of Waterloo (Canada). He is currently a researcher at CBPF and a Scientist of Our State (CNE) by FAPERJ. He works in the field of Physics, with emphasis on Quantum Information and Nuclear Magnetic Resonance (NMR), developing experimental research in NMR techniques, optical detection of resonance signals and in superconducting devices.
From Search to Structure: Connecting Quantum Walks and Variational Algorithms
Monday, 3:00 PM to 3:30 PM
Quantum algorithms for search and optimization can be viewed through two complementary paradigms: variational quantum circuits and quantum walks. Each offers distinct insights into how interference, structure, and parameterization shape computational performance. In this talk, I will explore connections between Grover-inspired variational algorithms and spatial quantum walks on graphs, highlighting analytical and numerical results from both approaches. Topics will include expressivity and performance bounds in Grover-based QAOA, as well as the role of potentials and self-loops in enhancing or degrading quantum walk search under realistic noise. The discussion concludes with reflections on how these ideas inform the design, simulation, and teaching of quantum optimization algorithms using frameworks such as Qiskit.
Franklin de Lima Marquezino
Federal University of Rio de Janeiro
Franklin de Lima Marquezino is an Associate Professor at the Federal University of Rio de Janeiro (COPPE/Systems and Duque de Caxias Campus). He holds a PhD in Computational Modeling from the National Laboratory for Scientific Computing (2010) and conducted postdoctoral research at the Quantum Computer Science Center of the University of Latvia (2024-2025). He is co-author of the book "A Primer on Quantum Computing" (Springer) and winner of the CAPES Thesis Award 2011. He serves on the editorial board of Theoretical Computer Science and on scientific committees of international conferences including IEEE Quantum Week. His research focuses on quantum algorithms, quantum walks, and theoretical aspects of quantum computing, being recognized as an IBM Qiskit Advocate for his practical contributions to the field.
Quantum Computing in Materials Discovery
Monday, 3:30 PM to 4:00 PM
The application of quantum computing is transforming chemistry and materials science. In this presentation, I will outline how our team combines quantum algorithms with first-principles simulations and AI tools for improving computational discovery outcomes. As application examples, we explore materials for carbon dioxide capture and energy storage.
Dr. Mathias Steiner is a physicist and research manager at IBM with over 20 years of industrial R&D experience acquired across three continents. As co-lead of IBM Research's Sustainability initiative, he investigates the convergence of artificial intelligence, hybrid cloud, and quantum computing to accelerate materials discovery. He joined IBM in 2007 at the TJ Watson Research Center (NY), where he conducted pioneering research on functional materials and nanoscale devices. He currently coordinates a global team of researchers and leads strategic projects in sustainability and quantum technologies. He is a Fellow of the American Physical Society, received the SPIE Early Career Achievement Award, and multiple IBM outstanding achievement awards.
MW quantum sensors using hot Rydberg atoms
Monday, 4:00 PM to 4:30 PM
Atom-based sensing systems provide exceptional advantages owing to their intrinsic self-calibration as quantum entities. The physical properties of atoms are identical for all atoms of a given species, regardless of their location in the universe. This fundamental stability, anchored in the constants of nature, offers major benefits, as atomic systems are inherently immune to manufacturing variations and aging effects. In this context, Rydberg atoms have garnered significant attention in recent years due to their extraordinarily wide range of transition frequencies, extending from 1 MHz to 1 THz. This extensive range stems from the Coulomb potential, which gives rise to an infinite series of electronic states and, consequently, an infinite number of Rydberg transitions. These transitions exhibit exceptionally large dipole matrix elements, often exceeding those of the D* transition in alkali atoms by factors of 100 to 1000. Such properties make Rydberg atoms extraordinarily sensitive to electromagnetic radiation across their transition frequency spectrum. In this seminar, I will discuss the use of hot Rydberg atoms as microwave quantum sensors and their potential to drive progress in quantum technologies.
Luis Gustavo Marcassa
São Carlos Institute of Physics/USP
Holds a degree in Physics from the São Carlos Institute of Physics (USP), and a doctorate in atomic and molecular physics from the same institution. He completed a doctoral internship at the University of Maryland and a postdoctoral fellowship at the University of Michigan, in the United States. He returned to Brazil in 1996, where he was hired as an assistant professor at IFSC. In 2001, he obtained the title of Associate Professor (Livre-Docente) from IFSC and in 2009 the title of Full Professor (Professora Titular).
BosonSampling with a linear number of modes
Wednesday, 3:00 PM to 3:30 PM
BosonSampling is one of the leading candidate models for a demonstration of quantum computational advantage. However, there are still important gaps between our best theoretical results and what can be implemented realistically in the laboratory. One of the largest gaps concerns the scaling between the number of modes (m) and number of photons (n) in the experiment. The original proposal by Aaronson and Arkhipov, as well as all subsequent improvements, required m to scale as n^2, whereas most state-of-the-art typically operate in a regime where m is linear in n. In this talk, I will describe how our recent work bridges this gap by providing evidence that BosonSampling remains hard even for m as low as 2n. I will review the template for proofs of computational advantage used in BosonSampling and other proposals, and discuss how we solved the new challenges that appear in this regime.
Daniel Brod
Federal Fluminense University
Holds a degree in Physics (Bachelor's) from the University of Brasília (2008) and a doctorate in Physics from the Federal Fluminense University (2014) in the area of Quantum Computing. He completed two and a half years of postdoctoral work at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, and one year of postdoctoral work at the Federal Fluminense University. He is currently a professor at the Institute of Physics at the Federal Fluminense University. His research lines include restricted models of quantum computing, quantum computing with linear optics and cross-Kerr nonlinearities, and foundations of quantum mechanics.
Twin-Field QKD: fundamentals and implementation challenges
Friday, 3:00 PM to 3:30 PM
The Twin-Field QKD (TF-QKD) protocol was proposed as an innovative solution to overcome the maximum range limitations in quantum cryptography systems. By exploring interference between weak coherent states sent by Alice and Bob and measured at an intermediate node, Charlie, TF-QKD enables secret key rates that scale more favorably with distance, making QKD systems more resilient to channel losses.
This talk will discuss the fundamentals and experimental challenges of TF-QKD, including phase and polarization stabilization in long optical links, synchronization between independent transmitters, and noise mitigation. New optical system architectures aimed at integrating multiple nodes in the same quantum network will also be presented, enabling the practical implementation of a metropolitan quantum communications infrastructure.
Guilherme Penello Temporão
Pontifical Catholic University of Rio de Janeiro
Holds a doctorate in Electrical Engineering from the Pontifical Catholic University of Rio de Janeiro (2007), with 2 years of doctoral internship in the Applied Physics Group at the University of Geneva (2004-2006). He is currently an Associate Professor at PUC-Rio and teaches undergraduate and graduate courses, in addition to working as a researcher in the areas of quantum communication, quantum metrology and quantum computing. He is the principal researcher of the Rio Quantum Network project and coordinator of NITeQ/PUC-Rio (Interdisciplinary Center for Quantum Technologies). His other areas of interest include quantum networks, optoelectronic instrumentation and Engineering education.
Electrical energy cost of arbitrary state preparation with programmable integrated photonic circuits
Friday, 3:30 PM to 4:00 PM
As quantum computing platforms transition from laboratory proofs-of-principle to larger scale computers, and technology and algorithms mature, it is important to start considering what might be the energetic cost of using quantum computers to perform meaningful tasks. Programmable photonics are typically composed of arrays of Mach-Zehnder Interferometers (MZI), each equipped with two phase modulators. It has been known for over three decades that such arrays can implement arbitrary unitary operations on N optical modes, serving as resources for (gaussian) boson sampling computations and arbitrary operations on qudits. While they are not by themselves universal for quantum computation on qubits, it is possible to use them to implement the necessary gates, in (probabilistic or quasi-deterministic) gate-based linear optical quantum computing (LOQC), as well as to implement the adaptive measurements in measurement- and fusion-based photonic quantum computing (MBQC and FBQC). In this work, we discuss the energy costs related to programming these arrays, considering integrated photonic circuits made of waveguides and electro-optical modulators, to perform arbitrary quantum state preparation. This task was chosen because its exponential difficulty can serve as a tentative upper bound to the expected energy consumption of a given platform. We will focus on gate-based approaches, for which there are well-established optimized protocols, and discuss the implications for MBQC and FBQC, which are currently hegemonic in LOQC.
Pierre Louis de Assis
University of Campinas
I completed my undergraduate studies (2004), Master's (2007), and PhD (2011) at the Federal University of Minas Gerais. Between 2012 and 2013, I worked as a postdoctoral researcher at the Institut Néel in Grenoble, France. From 2014 to 2016, I returned to UFMG for another postdoctoral fellowship. Since 2017, I have been a professor in the Department of Applied Physics at IFGW. Since my PhD, I have worked in the area of experimental quantum information, with a focus on optics. Currently, my main interest is the development of key technologies to enable quantum information processing using light.
Beyond Static Noise Mitigation: Drift-Resilient SPAM quantum error mitigation in quantum computers
Friday, 4:00 PM to 4:30 PM
Despite significant advances in quantum hardware, noise remains a major obstacle to achieving practical quantum advantage. While full Quantum Error Correction (QEC) represents the long-term solution, its resource requirements are unfeasible for current Noisy Intermediate-Scale Quantum (NISQ) devices. In the NISQ era, Quantum Error Mitigation (QEM) techniques are therefore essential for extracting meaningful results. This presentation introduces a novel framework for mitigating State Preparation and Measurement (SPAM) errors. Our method is specifically designed to be resilient to temporal drift, a critical challenge for conventional static calibration methods*and is fully compatible with other existing QEM protocols.
Jader Pereira dos Santos
The Hebrew University of Jerusalem
Jader Pereira dos Santos is a postdoctoral researcher at The Hebrew University of Jerusalem since 2021, under the supervision of Prof. Raam Uzdin. He completed his first postdoctoral fellowship at the University of São Paulo (2016-2020) with Prof. Gabriel Teixeira Landi. He holds a PhD in Physics from the Federal University of ABC (2011-2015), with a sandwich period at Queen's University Belfast under the supervision of Prof. Mauro Paternostro, and a Master's degree from the State University of Ponta Grossa (2009-2011), where he also earned his undergraduate degree (2005-2008), having been advised by Prof. Fernando Luis Semião da Silva in both degrees. His current research focuses on the development and implementation of error mitigation techniques in quantum computers.
