Qibo, a new open source framework for quantum simulation with hardware acceleration

We are very excited to present Qibo, the quantum simulator made by some members of Quantic in collaboration with researchers from the Technology Innovation Institute in Abu Dhabi and the University of Milano. The full paper can be read in arXiv, and the source code has been uploaded to GitHub.

Qibo is a new open-source software for fast evaluation of quantum circuits and adiabatic evolution which takes full advantage of hardware accelerators. In this work we introduce a new quantum simulation framework that enables developers to delegate all complicated aspects of hardware or platform implementation to the library so they can focus on the problem and quantum algorithms at hand. This software is designed from scratch with simulation performance, code simplicity and user friendly interface as target goals. It takes advantage of hardware acceleration such as multi-threading CPU, single GPU and multi-GPU devices.

Qibo has plenty of functionalities that will make the work with quantum circuits much user-friendlier (up), as well as some predefined models (down)

Qibo is constructed as a stack with the structure below. This structure allows the software to have a high level API together with some useful algorithms serving as tools to be used by quantum developers. Then, backends and operators, constructed on top of TensorFlow, manage all the processes needed to obtain as much efficiency as possible by specializing operators for CPU and GPU. The abstraction layer performs the operations themselves.

Qibo includes all precision and hardware configurations available for other programming languages in the same package. In addition, switching from one configuration to another is easily done by writing a pair of lines of code. Every configuration is optimal for some conditions.

The performance of Qibo is comparable or superior to previous programming languages for quantum simulation. For an instance of Quantum Fourier Transform (QFT), the best results are obtained for large numbers of qubits. In the case of adiabatic evolution, also great advantages have been achieved.

The future work serving as continuation for this first release of Qibo will include a scheme to send Qibo-jobs to quantum hardware through a remote server and a scheduler. This way, many users will be able to submit their calculations to a quantum processor.

The hash preimage, a new paper by Quantic members

Recently the paper Quantum Search for Scaled Hash Function Preimages has been published in arXiv as a preprint. This is a joint work of S. Ramos-Calderer, E. Bellini, J. I. Latorre, Marc Manzano and Victor Mateu
We provide an explicit implementation of Grover’s algorithm for a search of preimages of Scaled down Hash functions. This allows for a thorough understanding of the scaling and difficulties when addressing particular hash constructions.
Hash primitives based on Addition Rotation and Exclusive OR (ARX) operations are easier to attack due to their easier mapping to a quantum circuit, while AND and OR gates need extra quantum resources.
An entanglement entropy analysis during the application of Grover’s algorithm reveals that maximum entanglement is reached during the first application of the Grover oracle, which implies that no classical simulation based on Tensor Networks would be of relevance.

Qilimanjaro Quantum Tech SL is established

Recently, some members of QUANTIC have established Qilimanjaro Quantum Tech SL, a new spin-off of our three institutions: the University of Barcelona, Barcelona Supercomputing Center and Instituto de Física de Altas Energías. The PIs of QUANTIC, Dr. José I. Latorre, Dr. Artur Garcia-Saez and Dr. Pol Forn-Díaz, together with experts from the IT and M&A sectors will lead this project.

The future will be Quantum, and Qilimanjaro’s aim is to play an important role in the development of quantum technologies, both in the hardware as in the algorithmic parts. Qilimanjaro will also construct all the structure that is needed to run quantum algorithms in a own-made quantum computer. This quantum hardware will make use of high-quality qubits to perform adiabatic quantum computation. This technique has got enough potential as to offer actual optimization applications in the advent of the quantum era.

This technology will be available in the mean-term future as a cloud service, allowing all users to explore the capabilities of quantum computers.


Do you want to know more? Check out HPC Wire



Quantic turns 3 years old

Last week Quantic celebrated its third birthday! Although the COVID-19 situation did not let us to hold the full party, as some of the members could not join the event, it is nice to see how the group grows and improves. This last year has been full of surprises, full of news, full of special moments. This has been, as for most of people, a difficult year. However, at the end of the day year, we are allowed to look back and confess: wow, what a year. Cheers to all who made it possible.

The next months promise to be amazing and exciting, great expectations are yet to be fulfilled. Old friends coming and going, new people getting to know us, new projects to accomplish, discoveries hidden ahead of us… Let us hope the future is as brilliant as in our minds.

Happy Birthday!

New open postdoc position

The QCT group at IFAE has an open postdoctoral position for the SiUCs project funded under the Quantera program. More information is available here and by contacting Pol Forn.

The newly established QCT group in Barcelona offers a postdoctoral position within the project SiUCs ( Superinductor-based Quantum Technologies with Ultrastrong Couplings) funded by the European QuantERA program.

The tasks for this position will involve design, fabrication and measurement of superconducting qubit devices coupled to resonator modes to study the physics of this system in regimes of ultrastrong coupling, and its consequences in superconducting-based quantum technologies.

The candidate will closely work in collaboration with the rest of partners in the SiUCs consortium:

  • Nicolas Roch (Néel Institute CNRS, Grenoble, FR)
  • Ioan Pop (Karlsruhe Institute of Technology, DE)
  • Milena Grifoni (Regensburg University, Institute for Theoretical Physics, DE)
  • Miroslav Grajcar (Institute of Physics, Slovak Academy of Sciences, SK)
  • Elisabetta Paladino (Consiglio Nationale delle Richerche Catania, IT)

Interested candidates are expected to hold a doctoral degree in Physics and must be experienced in experimental superconducting qubit device techniques in at least one of the following areas: quantum optics with superconducting devices, qubit coherent control, quantum simulations with superconducting devices.

Applications should be sent to Pol Forn-Díaz and should include an updated CV with a letter of intent or motivation, and arrange for two or three letters of recommendation. Sending CVs to IFAE implies consent to the legal warning at the bottom of IFAE’s homepage, see the job posting at IFAE’s website.

The appointment will be for a two years term, with the possibility to renew for a third year.


IFAE is an equal opportunity employer committed to diversity in the workplace, and we welcome applications from all qualified candidates. Women are particularly encouraged to apply.

Great News for our PI

Dear all,

we are glad to announce that the Principal Investigator of Quantic, José Ignacio Latorre, has been selected as the new director of the Center for Quantum Technologies in Singapore. We will join the CQT the next 27th July, taking over from founding director Artur Ekert.

Have the best of lucks in this new opportunity!


Bojos per la supercomputació

The Quantic members Carlos Bravo-Prieto and David López-Núñez have shared some time with high-school students that are ”crazy for supercomputing”.

First, they have learnt them the basic concepts of quantum mechanics, a necessary step to understand quantum computing, as well as the potential applications of it.

Presentació powerpoint sobre física quàntica. En aquesta plana, hi ha la introducció a aquesta disciplina.

Then, the foundations of quantum computing have been explained, such as how to represent a qubit in the Bloch sphere, (thanks to Quantum Fracture for the nice drawings)


Finally, our students have learnt to simulate quantum algorithms in classical computers.


Hopefully, some of them will join us in the future in this amazing adventure of researching in Quantum Computing. Thank you very much for your attention, and have luck in your brilliant futures!

New paper by Quantic members!

Diego García-Martín and José Ignacio Latorre recently published “The Prime state and its quantum relatives”, together with E. Ribas, S. Carrazza and G. Sierra.Congratulations! You can see this paper in arXiv (arxiv.org/abs/2005.02422) and scirate (scirate.com/arxiv/2005.024)

The Prime state is the uniform superposition of all the computational-basis states corresponding to prime numbers. This state encodes, quantum mechanically, arithmetic properties of the primes. Moreover, it can be efficiently created on a quantum computer.

In this paper, it is shown that the Quantum Fourier Transform of this state provides direct access to Chebyshev-like biases in the distribution of primes. Also, the entanglement traits of the Prime state are studied. These reveal correlations between prime numbers. In particular, the reduced density matrix for natural bi-partitions is characterized by the Hardy-Littlewood constants.

A relation is found between the scaling of the von Neumann entropy and the Shannon entropy of half the density of square-free numbers. This relation also holds when considering qudit bases, showing this property is intrinsic to the primes. It also holds when considering states defined from prime numbers belonging to arithmetic progressions.



The entanglement of other quantum number-theoretical states is also studied.
An open-source library that diagonalizes matrices using floats of arbitrary precision has been developed for this paper. In summary, a novel approach to Number Theory using the tools of Quantum Information Theory.

Outreach in Quantic

Quantic group has collaborated in a new outreach article for the Journal “Compàs d’Amalgama” in the University of Barcelona. Carlos Bravo-Prieto, Diego García-Martín and Adrián Pérez-Salinas wrote “Computació i supremacia quàntica, per què tothom parla d’això?” (Quantum computing and supremacy, why does everybody talk about that?) You can all read it here (in Catalan)


New paper by the theory team: measuring the tangle

Measuring the tangle of three-qubit states, by A. Pérez-Salinas, C. Bravo-Prieto, D. García-Martín and J. I. Latorre


In this paper, the authors propose a method for transforming an unknown three-qubit state into its canonical form up to phases. This transformation can be achieved variationally and may be used to estimate the tangle. Simulations on this method have been performed.

The tangle is a three-qubit entanglement invariant that quantifies genuine tripartite entanglement. The state with maximum tangle is the GHZ state (and its local transformations). The distribution of tangle for random three-qubit states is depicted below.


The canonical form up to phases can be achieved when the number of measurements of three possible elements in the computational basis are zero. In this form, the tangle is easily measured. The canonical form can be cast by applying local unitaries on each qubit.


The tangle is affected by errors in the circuit. To mitigate these errors, a post-selection scheme can be applied after measuring the output state. This post-selection consists of discarding those results that should not appear in the canonical form.

First, the authors have analyzed the GHZ state. The estimation of the tangle with this method provides lower values as the errors (“t”) in the circuit increase. Post-selection mitigates the errors considerably.


This behavior has found to be a common tendency for many different random states. In the figure depicted below, each dot corresponds to a random three-qubit state.
With errors comparable to those in the state-of-the-art quantum hardware, the tangle presents a mean underestimation of ~30%. Post-selection lowers this result to ~17%.
Although the method herein presented does not provide any speed up respect to quantum tomography, it can be used as a module for other algorithms, such as a classifier.
UPDATE: This paper has been published in Entropy