New paper on Two-photon Quantum Rabi model

A new publication has appeared led by Dr. Pol Forn-Díaz on the theoretical implementation of the two-photon quantum Rabi model. A purely genuine, two-photon interaction is a very intriguing effect, and it is very difficult to find a system in nature that exhibits such phenomenon. In this work, which is a collaboration with the group of Prof. Solano at UPV-EHU in Bilbao, the team found a superconducting circuit which is described by a purely two-photon interaction. The work also investigated the very intriguing phenomenon of a spectral collapse, when the two-photon interaction exceeds a certain critical value and the spectrum of the systems becomes unbounded. The work appeared in Physical Review A. The full reference is Phys. Rev. A 97, 013851 (2018).

This circuit, consisting of a dc-SQUID and a flux qubit, implements the two-photon quantum Rabi model.


New group member

MSc. Chris W. Warren joined the QUANTIC group as a ‘Research Engineer’. Chris will join the experimental team to set up the first generation of experiments with superconducting qubits. Chris just finished his Master thesis at the Institute for Quantum Computation (University of Waterloo) under the supervision of Prof. C. M. Wilson.

Welcome Chris!

Pol Forn-Díaz awarded MISTI Seed Fund

Dr. Pol Forn-Díaz has been awarded the MIT International Science and Technology Initiative Seed Fund, together with MIT Professor William D. Oliver and Dr. Simon Gustavsson. The 20,000 USD grant is awarded by the MIT-Spain – “La Caixa” Foundation.

The award will strengthen the already existing collaboration between the BSC and MIT groups in their project to build a superconducting quantum processor.

QUANTIC group highlighted at the BSC day

The Barcelona Supercomputing Center celebrates its special day when the winter holiday period approaches. This year the event was marked by the recent news of the award to BSC of the project EuroHPC to coordinate the endeavor of producing European-made computer chips, and become a sovereign chip producer. More extended coverage of the news here (in Spanish).

During the presentation by BSC director Mateo Valero and associate director Josep Martorell, an overview of the year 2017 was given, with special emphasis on the start of MareNostrum 4. As a highlight of 2017, the creation of our group QUANTIC had its moment, particularly since some are already wondering when will BSC host a quantum computer.

Josep Martorell, BSC vice director, highlighting the creation of Quantic Group.

Consortium on coherent quantum annealing meets in Barcelona

On Friday December 1st, an European consortium gathered at BSC to organize a project to build a Coherent Quantum Annealer using the technology of superconducting circuits. The BSC group led by Dr. Pol Forn-Díaz and Prof. J. I. Latorre will coordinate the consortium.

The consortium will participate in the FET Flagship on Quantum Technologies call. With this call, the European Union aims at bringing the European research at the forefront worldwide in the development of quantum technologies. The consortium led by the BSC team is formed out of researchers from Germany, Switzerland and Spain.

The FET call on quantum technologies was launched after the publication of the Quantum Manifesto endorsed by many important European scientists as a response to the growing industry on quantum technologies particularly in the US and China.

New article on Maximal Entanglement

Alba Cervera-Lierta and José Ignacio Latorre’s work on ‘Maximal Entanglement Generation in High Energy Physics’ has been accepted to SciPost!

This work explores how maximal entanglement is generated at the fundamental level in particle processes such as electron-electron scattering or pair annihilation into photons. It is also shown that the requirement of maximal entanglement constrains the structure of the fundamental interaction. Maximal entanglement is used to obtain a non-trivial prediction for the value of the weak mixing angle, a free parameter of the Standard Model of particles. The results are a first step towards understanding the connections between maximal entanglement and the fundamental symmetries of high-energy physics.

Feynman diagram for electron-positron scattering into a muon-antimuon pair at tree level

The reference of the article is SciPost Phys. 3, 036 (2017).

New article on single photon generation

A new article led by QUANTIC member P. Forn-Díaz has been recently published on Physical Review Applied. The article presents a new method of generating single microwave photons on demand. The new technique consists in controlling the position of nodes of vacuum modes of a transmission line where a superconducting qubit is coupled. This control on the mode profile happens very quickly, in the nanosecond scale, and it results in a real-time tunable qubit-line interaction. This interaction produces photon wavepackets with a shape that can be nearly arbitrary.

Microscope image of the device used to generate single photons. Overlaid with the image are real data traces of single photons generated with a controlled delay

The work was carried out at the laboratory of Prof. Christopher Wilson at the Institute for Quantum Computing in the University of Waterloo (Canada). This result is very relevant for the deployment of microwave quantum networks and to connect sectors of future large-scale quantum computers. The reference of the paper is Physical Review Applied 8, 054015 (2017).

Official presentation of Quantic Group at RICE meeting

Last September 22nd, the Quantic Group at BSC was presented to the Quantum Information Network in Spain (Red de Información Cuántica de España, or RICE) meeting organized at the Barcelona Supercomputing Center.

The event was combined with talks by researchers from RICE. More information at the official event site.

Here are some images of the event:

José Ignacio Latorre introducing the event.
Pol Forn-Díaz explaining the future project at BSC.
Artur García-Sáez introducing quantum simulation.
Juan José García-Ripoll presenting his team at IFF.
Alessio Celi presenting his work on simulating magnetic fields in cold atoms.
Daniel Alsina describing how he programmed the IBM Quantum Processor.
Germán Sierra presenting his work on number theory and quantum algorithms.
Bruno Julia presenting his work on solving number partitioning problems in trapped ions.
Enrique Rico describing the projects at the QUTIS group in Bilbao.
Juan Bermejo-Vega explaining his recent work on verifying quantum speed-up.