Quantum computers are shifting the paradigm of information processing from the classical bit to the quantum bit (qubit) thanks to the massive parallelisation they can offer.
They are among the most disruptive technologies of the 21st century, with their power coming from the complexity of quantum states that can be created, manipulated, and measured by a quantum computer.
Quantum computers operate by applying a set of quantum gates to an initial state to achieve a final state that encodes the solution to a computationally hard problem, e.g. evaluating the energy of a molecule or the shortest path in a travelling salesman problem.
Efficiently implementing precise multi-qubit gates is essential for achieving fault tolerant quantum computing. Quantum optimal control (QOC) enables their realisation by designing and optimising electromagnetic pulses that drive the quantum system’s behaviour.
The performance of a quantum gate is measured by its ability to achieve the desired transformations with precision and robustly in the presence of noise from control imperfections and random thermal energy exchanges between the qubits and their surroundings.
While progress has been made, current quantum gate implementations face significant challenges in scaling to solve meaningful and large-scale problems.
Reinforcement learning (RL) is an active research branch in artificial intelligence, in which an agent interacts dynamically with its environments by observing, acting and learning through feedback. The agent receives a reward for each action performed – positive for actions which lead to a specific goal and negative for any missteps. RL has been successfully applied to many applications, from robotics to finance and industry automation.
The Reinforcement Learning for Quantum Optimal Control (RLQuantOpt) project is funded by Xjenza Malta through the FUSION Research Excellence Programme to develop RL techniques to generate electromagnetic pulses that implement quantum gates such that they align with the fundamental quantum speed limit – the theoretical minimum time required for a quantum system to evolve – achieving results that standard numerical optimisation techniques struggle to replicate.
The research team at the University of Malta is collaborating with two prestigious universities, Freie Universität Berlin (Germany) and the University of Salzburg (Austria), and has successfully demonstrated the ability of RL approaches to find pulse shapes that achieve efficient quantum gate implementation within the constraints of the quantum speed limit.
Prof. Ing. Gianluca Valentino (Department of Communications and Computer Engineering) and Prof. Tony Apollaro (Department of Physics), from the University of Malta, are the principal investigator and co-investigator respectively of the RLQuantOpt project. The research team also includes research support officers Dr Leander Grech and Dr Mirko Consiglio.
Sound Bites
• Scientists have succeeded in controlling the structure and function of biological membranes with the help of ‘DNA origami’. The system they developed may facilitate the transportation of large therapeutic loads into cells. This opens up a new way for the targeted administration of medication and other therapeutic interventions. Thus, a very valuable instrument can be added to the toolbox of synthetic biology.
• Researchers have discovered what may be the world’s oldest three-dimensional map, located within a quartzitic sandstone megaclast in the Paris Basin. The Ségognole 3 rock shelter, known since the 1980s for its artistic engravings of two horses in a Late Palaeolithic style on either side of a female pubic figuration, has now been revealed to contain a miniature representation of the surrounding landscape.
For more soundbites, listen to Radio Mocha every Saturday at 7.30pm on Radju Malta and the following Monday at 9pm on Radju Malta 2 https://www.fb.com/RadioMochaMalta/.
DID YOU KNOW?
• In the early 20th century, there was a panic about the dangers of listening to the radio. In 1929, the New York Times claimed people would fall ill from trying to process information ‘at the jazz rate’.
• JANUARY BRAIN –lack of energy and motivation you feel when going back to work after the Christmas holidays.
• Apart from ligers (lion-tiger hybrids) and tigons (tiger-lion hybrids), there are also lion-tigon hybrids called litigons; lion-leopard hybrids called leonards; leopard-jaguar hybrids called lepjags; and lion-lepjag hybrids called lijaguleps.
• From 1264 to 1827, anyone who received a Master of Arts degree from Oxford had to swear that they would never forgive Henry Symeonis. By 1608, no one knew who he was or what he had done.
For more trivia, see: www.um.edu.mt/think.