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Guilherme B Xavier

Associate Professor, Head of Division, Docent

My main research focus is on experimental quantum communications, specializing in quantum key distribution, propagation of entanglement, optical fibers and associated optoelectronic instrumentation.

I have obtained my PhD degree in 2009 in Electrical Engineering at the Pontifical Catholic University of Rio de Janeiro in Brazil, working on automatic polarization stabilization for quantum communication systems over optical fibers and quantum key distribution experiments. I remained as a post-doctoral researcher working on active phase stabilization for long optical fiber interferometers until 2011, where I moved to the Electrical Engineering Department of the Universidad de Concepción (UdeC) in Chile, as an Assistant Professor.

There I started a new lab on quantum communication and led novel experiments on quantum communication with energy-time entangled photons. I also collaborated strongly with the Quantum Optics group at the Physics department at UdeC, where we performed many experiments using high-dimensional spatial photonic quantum systems, in fields such as quantum cryptography and quantum contextuality.

Since May 2017 I have joined the Faculty at the Department of Electrical Engineering of Linköping University, at the Information Coding Division as a Senior Lecturer (Universitetslektor). I am heading the newly started Quantum Communications Laboratory, focusing on research of quantum communications over next-generation telecommunication optical fibers designed for spatial division multiplexing.

Teaching

I am currently teaching TSIN02 - Internetworking, and TSIT02 - Computer security. Both are given at the Fall term.

Selected publications

G. Cañas, N. Vera, J. Cariñe, P. González, J. Cardenas, P. W. R. Connolly, A. Przysiezna, E. S. Gómez, M. Figueroa, G. Vallone, P. Villoresi, T. Ferreira da Silva, G. B. Xavier, and G. Lima, “High-dimensional decoy-state quantum key distribution over multicore telecommunication fibers”, Physical Review A 96, 022317 (2017). https://journals.aps.org/pra/abstract/10.1103/PhysRevA.96.022317

G. Carvacho, J. Cariñe, G. Saavedra, A. Cuevas, J. Fuenzalida, F. Toledo, M. Figueroa, A. Cabello, J.-Å. Larsson, P. Mataloni, G. Lima and G. B. Xavier, “Post-Selection Loophole-Free Bell Test over an Installed Optical Fiber Network”, Physical Review Letters 115, 030503 (2015).
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.030503

A. Cuevas, G. Carvacho, G. Saavedra, J. Cariñe, W. A. T. Nogueira, M. Figueroa, A. Cabello, P. Mataloni, G. Lima and G. B. Xavier, “Long-distance distribution of genuine energy-time entanglement”, Nature Communications 4, 2871 (2013).
https://www.nature.com/articles/ncomms3871

T. Ferreira da Silva, D. Vitoreti, G. B. Xavier, G. C. do Amaral, G. P. Temporão and J. P. von der Weid, “Proof-of-principle demonstration of measurement-device-independent quantum key distribution using polarization qubits”, Physical Review A 88, 052503 (2013).
https://journals.aps.org/pra/abstract/10.1103/PhysRevA.88.052303

S. Etcheverry, G. Cañas, E. S. Gómez, W. A. T. Nogueira, C. Saavedra, G. B. Xavier and G. Lima, “Quantum key distribution session with 16-dimensional photonic states”, Scientific Reports, 3, 2316, (2013).
https://www.nature.com/articles/srep02316

G. B. Xavier and J. P. von der Weid, “Stable single-photon interference in a 1 km Mach-Zehnder fiber optical interferometer with continuous phase adjustment”, Optics Letters, 36, 1764 (2011).
https://www.osapublishing.org/ol/abstract.cfm?uri=ol-36-10-1764


For a complete and updated list, please visit my Google Scholar profile

Publications

Francesco B. L. Santagiustina, Costantino Agnesi, Alvaro Alarcon, Adan Cabello, Guilherme B Xavier, Paolo Villoresi, Giuseppe Vallone,  Experimental post-selection loophole-free time-bin and energy-time nonlocality with integrated photonics, Optica 11:498-511 (2024)  https://doi.org/10.1364/OPTICA.499247  https://arxiv.org/abs/2302.06522

Joakim Argillander, Alvaro Alarcon, Chunxiong Bao, Chaoyang Kuang, Gustavo Lima, Feng Gao, Guilherme B Xavier,  Secure quantum random number generation with perovskite photonics, QUANTUM COMPUTING, COMMUNICATION, AND SIMULATION IV, Proceedings of SPIE, SPIE-INT SOC OPTICAL ENGINEERING (2024)  https://doi.org/10.1117/12.2692061

Alvaro Alarcon, Joakim Argillander, Daniel Spegel-Lexne, Guilherme B Xavier,  Dynamic generation of photonic spatial quantum states with an all-fiber platform, Optics Express 31:10673-10683 (2023)  https://doi.org/10.1364/OE.481974

Alvaro Alarcon, Santiago Gomez, Daniel Spegel-Lexne, Joakim Argillander, Jaime Carine, Gustavo Canas, Gustavo Lima, Guilherme B Xavier,  All-in-Fiber Dynamically Reconfigurable Orbital Angular Momentum Mode Sorting, ACS Photonics 10:3700-3707 (2023)  https://doi.org/10.1021/acsphotonics.3c00825

Alvaro Alarcón, Santiago Gómez, Daniel Spegel-Lexne, Joakim Argillander, Jaime Cariñe, Gustavo Cañas, Gustavo Lima, Guilherme B. Xavier, All-in-fiber dynamic orbital angular momentum mode sorting (2023)  https://arxiv.org/abs/2306.16472

News

Two persons in a room full och wires and optical instruments.

Quantum theory and information theory connected

With the help of a new experiment, researchers at LiU, have succeeded in confirming a ten-year-old theoretical study, which connects the complementarity principle with information theory.

Blue laser in dark laboratory.

Quantum communication tested on a large scale

So-called quantum encryption will ensure the security of sensitive information – but this new technology has to be tested outside the lab environment. LiU is therefore taking part in a project studying secure communication channels of the future.

Two persons in a lab with a laserinstrument infront of them on a table full of cables.

Better cybersecurity with new material

Digital information exchange can be safer, cheaper and more environmentally friendly with the help of a new type of random number generator for encryption developed at LiU. The technology paves the way for a new type of quantum communication.

News

Two persons in a room full och wires and optical instruments.

Quantum theory and information theory connected

With the help of a new experiment, researchers at LiU, have succeeded in confirming a ten-year-old theoretical study, which connects the complementarity principle with information theory.

Image of photonic chip.

Improved quantum cryptography with optical circuit

An optical circuit capable of ensuring the security of quantum cryptography. The idea that researchers Alvaro Alarcón and Guilherme B. Xavier had five years ago has now been tested and could pave the way for the future of secure communication.

Blue laser in dark laboratory.

Quantum communication tested on a large scale

So-called quantum encryption will ensure the security of sensitive information – but this new technology has to be tested outside the lab environment. LiU is therefore taking part in a project studying secure communication channels of the future.

Staff at ICG

About the division

About the department