New paper by the theory team, now with more finance!

This is Quantic’s last article “Quantum unary approach to option pricing“, by Sergi Ramos-Calderer, Adrián Pérez-Salinas, Diego García-Martín, Carlos Bravo-Prieto, Jorge Cortada, Jordi Planagumà, José I. Latorre, available in ArXiv

This paper introduces a novel algorithm for European option pricing that uses the unary representation of the asset price. That is, each qubit maps into a single price of the underlying asset.

The amplitude distributor that uploads the expected price evolution to the qubit register and the circuit that encodes the estimated payoff into an ancilla are remarkably simple in the unary representation.

The amplitude distributor only requires first neighbor interactions between qubits, therefore a simplified chip architecture is enough to run the algorithm.

This scheme allows for a post-processing procedure that results in error mitigation for Noisy Intermediate-Scale Quantum devices. This algorithm is more robust to noise their usual binary
counterparts.

Option pricing in this unary representation can be beneficial for near-term quantum computers.

New paper by the Theory Team!

This is Quantic’s last article “Quantum observables for continuous control of the Quantum Approximate Optimization Algorithm via Reinforcement Learning”, by A.Garcia-Saez & J.Riu, available in ArXiv
The article presents a classical optimization strategy for the Quantum Approximation Optimization Algorithm (QAOA) using Reinforcement Learning (RL). The algorithm is tested for several instances of the MAXCUT problem.

In general, RL approaches consist of discrete-time agent-environment interactions. The agent is provided with partial/total observation of the env. and maximizes the reward by acting into it.

The QAOA is implemented such that, at each step of an episode of arbitrary but fixed length p, a pair of parameter-dependent unitary transformations are applied to a Quantum state.
The values of the parameters are selected by the Deep RL agent using as inputs to the Neural Network a set of measurements of the Quantum state: The expected values of X and Z operators for each qubit as well as the clauses of the objective Hamiltonian individually.
At the end of each episode, the agent is rewarded with an amount equal to the expected value of the objective Hamiltonian in the final Quantum state of the environment. Results for an instance of a 3-regular graph with 13 vertices are shown.
Moreover, an incremental training strategy that allows the agent to reach larger p’>p episode lengths is successfully used for graphs with 21 qubits and p up to 25.

New experimental PhD student in Quantic!

This week, Fabian Zwiehoff from Germany has enrolled in our group as a new PhD student He did his studies at Karlsruhe Institute of Technology (KIT) and Technische Universität (TU) Berlin, and his Master’s project at ICFO on QKD. He will be working in the experimental team building superconducting quantum devices.

Welcome, Fabian!

Quantic at SONAR+D

Last summer, some members of Quantic were at Sonar+D, showing what a quantum computer looks like. It was a great experience, sharing some days with interesting people who exhibited their projects too. You can see here a little bit of the making of our quantum computer-toy.

We hope you enjoy it as much as we did!

People in this video: Pol Forn, Artur García, David López, Adrián Pérez

David López and his outreach

The Quantic member David lópez Núñez took part in the “Nit de Recerca Jove (European Researchers’ Night) 2019” hosted by CSIC, and gave a talk in his former High School in L’Hospitalet de Llobregat.

The title of the talks was: “Bricocuántica, ¿Cómo hacer un ordenador cuántico?” (Quantum DIY: how to make a quantum computer?)

      

 

It is always nice to get closer to new generations! Good job!

Our students this year (II)

The last of Quantic students, Rafael Luque, has presented his work with great results. Below one can find the updated list of grades

Bachelor:

Gabriel Fernández: Quantum Autoencoders; 8,6

Elies Gil: Variational Quantum Classifier; 9,7

Josep Lumbreras: Scaling of the energy and entropy errors in quantum circuits; 9,1

Santi Vallés: Design of infrared filters to improve the quality of a superconducting qubit; 9,3

Master:

Sergi Ramos: Maximal Entanglement in One-Loop Z Boson Decay; 9,1

Rafael Luque: Coherent control of a superconducting quantum bit; 9

 

Everyone did a great job at Quantic. Some of them will continue within the team, other people will spread their wings. The best of luck for you all!

New article by group’s member

PhD student Carlos Bravo-Prieto posted a pre-print article as the result of his summer stay at Los Álamos (NM, USA):

“Variational Quantum Linear Solver: A Hybrid Algorithm for Linear Systems”, by C. Bravo-Prieto (), R. LaRose (), M. Cerezo (), Y. Subasi, L. Cincio and P. J. Coles (). preprint:

In this work, they presented a variational quantum algorithm for solving the quantum linear system problem. On the analytical side, they derived efficient quantum circuits to estimate faithful cost functions, while showing that they are difficult to estimate classically.

Schematic of the quantum linear solver algorithm.

On the numerical side, they studied the scaling of the algorithm run time and found it to be efficient with respect to the condition number and the desired precision:

Furthermore, they implemented the variational algorithm in ‘s quantum computer, for particular problems up to a size of 32×32, which is the largest implementation of a linear system on quantum hardware:

We have a new PhD student!

This September a new PhD student will join the Quantic group. Sergi Ramos, who has already worked with us in his TFG (Treball de Fi de Grau) and TFM (Treball de Fi de Màster) will be from now on a member of the theory division of the group.

We know we have signed up a good researcher. Welcome (again) Sergi!

Our students this year

As the summer ends, we show here the Bachelor’s and Master’s theses our students have presented this year

Bachelor:

Gabriel Fernández: Quantum Autoencoders; 8,6

Elies Gil: Variational Quantum Classifier; 9,7

Josep Lumbreras: Scaling of the energy and entropy errors in quantum circuits; 9,1

Santi Vallés: Design of infrared filters to improve the quality of a superconducting qubit; 9,3

Master:

Sergi Ramos: Maximal Entanglement in One-Loop Z Boson Decay; 9,1

Rafael Luque: Coherent control of a superconducting quantum bit; 9

 

Everyone did a great job at Quantic. Some of them will continue within the team, other people will spread their wings. The best of luck for you all!

Quantic turns 2 years old

We are glad to announce that the Quantic family keeps growing. We are already two years old and have more members than ever. Congrats for these two years, and we look forward new and exciting science and projects.

We would like to welcome all new partners to Quantic, and to wish all the best for all people leaving the group. We will see each other again soon.