Researchers at the Aragon Institute of Nanoscience and Materials and two universities have created a magnetic molecule capable of executing simple quantum algorithms, the code can protect quantum qubits or qubits from noise. Progress has been made within the framework of the European project, which builds quantum processors based on these types of molecules.
Make Quantum computing Facing major technical challenges. One of the most important issues is the extreme vulnerability of quantum states (wave functions) to external noise.
So-called Error protection code Provide a solution to this problem, but need to increase the number elbow (Equivalent to bits in the quantum world), they encode each unit of information and therefore the fragile interconnection between them.
Therefore, creating a quantum processor that can correct errors without the need for an extremely complex architecture has become one of the priority goals in this field. Specifically, the integration of molecular-level algorithms is expected to help increase the capabilities of future quantum computers.
In this context, from the Aragon Institute of Nanoscience and Materials (INMA, The hybrid center of CSIC and the University of Zaragoza) and University of Barcelona and Parma (Italy) has shown that this simplest algorithm can be encapsulated in a single magnetic molecule.
The team developed an algorithm that can execute simple but vital quantum algorithms. It is a code that protects the quantum information stored in each molecule (qubit) from external noise.The work was published in a magazine Chemical science, Highlight it on the cover as a “weekly selection” (weekly selection).
Researchers from the Department of Inorganic Chemistry at the University of Barcelona used three rare earth atoms (two atoms and one cerium atom) to synthesize molecules, and experiments conducted at INMA examined their state in detail. Spin (A characteristic of a particle is related to its angular momentum).
The results show that each of them encodes a different qubit, is loosely coupled with its neighbors, and can characterize its response to microwave pulses and sensitivity to noise.
Scientists from the Department of Physics of the University of Parma used this information to successfully simulate the application of error correction protocols, where the spin of one atom encodes the information, and the other two atoms can detect and correct errors. . The spin of the cerium atom encodes quantum information, and the two atoms “warn” the existence of errors and allow the information to be restored.
New prototype quantum processor
This work is part of a project led by INMA. The purpose of the project is to build prototypes of quantum processors based on artificial magnetic molecules integrated into superconducting circuits, superconducting circuits control, read and communicate each of these basic units. Basic unit.
The plan is supported by two international cooperation projects, and the SUMO project was funded by the plan in 2018 Quante, Part of the program flagship European quantum technologyAnd project Fat man One of the European FET-OPEN calls that started in March this year.
FATMOLS has more than 3 million euros in global funding, with 9 well-known academic institutions from 5 countries and two top industry partners participating: Keysight, A global leader in microwave electronics and a computer giant IBM Corporation.
As shown in this work, the possibility of executing small algorithms on a molecular scale is one of the most important advantages of this proposal, because it can reduce the amount of communication between different points of a quantum circuit, and therefore reduce complexity
It also greatly improves the ability to integrate more qubits on the chip, which translates into more processor functions. When dealing with quantum simulations and calculations with real added value and applications, the combination of these two characteristics represents a competitive advantage over solutions based on superconducting qubits.
Emilio Macaluso, Marcos Rubín, David Aguilà, Alessandro Chiesa, Leoní Barrios, Jesús I. Martínez, Pablo J. Alonso, Olivier Roubeau, Fernando Luis, Guille mAromí and Stefano Carretta. “A miscellaneous metal [LnLn’Ln] The lanthanide complex acts as a qubit with embedded quantum error correction”. Chemical science September 9, 2020.