Optimization tasks in logistics or finance are considered the first possible applications of quantum computers. Physicists from Innsbruck have now developed a method with which optimization problems can be investigated on quantum hardware that already exists today. They have developed a special quantum gate for this purpose. […]
The development of quantum computers is being driven forward worldwide, and there are different concepts for how computing can be implemented with the possibilities of the quantum world. Many of them have already experimentally advanced into areas that can no longer be imitated on classic computers. But the technologies are not yet so far advanced that major computing problems can be solved with them, according to a statement from the University of Innsbruck. Science is therefore currently looking for applications that can be implemented on existing platforms. “We are looking for tasks that we can calculate on the existing hardware,” says Rick van Bijnen from the Institute of Quantum Optics and Quantum Information at the Austrian Academy of Sciences in Innsbruck. A team led by Rick van Bijnen and Wolfgang Lechner is now proposing a method with which optimization problems can be solved with the help of neutral atoms.
In order to develop scientifically and industrially relevant applications for existing quantum hardware in the near future, scientists are looking for special algorithms that structurally match the strengths of a quantum platform. “Thanks to this co-design of algorithms and experimental platforms, these systems also work without the error correction that is still difficult today,” explains Wolfgang Lechner from the Institute for Theoretical Physics at the University of Innsbruck. The physicists implement their optimization algorithm on neutral atoms trapped and arranged in optical tweezers. These can be programmed via the interaction of highly excited Rydberg states. In order to avoid the limitations of previous approaches, the physicists do not implement the algorithm directly, but use the so-called parity architecture, a scalable and problem-independent hardware design for combinatorial optimization problems, which Wolfgang Lechner developed together with Philipp Hauke and Peter Zoller in Innsbruck. In this way, only problem-dependent computational operations on individual quantum bits and problem-independent operations on several quantum bits are necessary for the optimization algorithm. Finding a direct and simple implementation for these four-qubit operations was the biggest challenge for the Innsbruck researchers. They have developed a special quantum gate for this. “We implemented the algorithm directly in the language of the experiment,” explains first author Clemens Dlaska. “In this way, the algorithm can be implemented on current quantum hardware by simply optimizing the duration of laser pulses in a feedback loop”.
Can be extended as required
The proposed concept makes it possible to investigate the performance of existing quantum hardware in solving relevant optimization problems for problem sizes that cannot currently be simulated on classical supercomputers. The fact that both the hardware platform and the software solution can be extended as much as desired without modifications is an important advantage of the new process, according to the press release.