Periodic Reporting for period 2 - AVaQus (ANNEALING-BASED VARIATIONAL QUANTUM PROCESSORS)
Período documentado: 2021-10-01 hasta 2023-09-30
The AVaQus project represents a launchpad towards developing a quantum computing technology based on quantum annealing with coherent superconducting qubits. The project defines coherent quantum annealers as those processors containing the following properties: being built out of qubits that retain coherence times much longer than the computation time; containing qubit-qubit interactions that have no classical analogue; the connectivity is high between qubit pairs; the annealer can be used beyond annealing problems, including hybrid quantum-classical variational problems following annealing-like processing techniques. The combination of all these properties results in a quantum device that has a high potential to overcome classical processors in the near term where no quantum error correction will be available. In addition, coherent quantum annealers can be scaled up in the long-run towards adiabatic quantum processors to perform universal quantum computation.
The goal of the AVaQus project is to develop a quantum annealer prototype of 5 coherent flux-like qubits, with interactions beyond the Ising model and a large connectivity map. This prototype will be used as a demonstrator for several proof-of-principle dynamical control techniques and theoretically study its applicability in larger-scale processors that could lead to a quantum advantage. The annealer prototype will also be used to implement quantum algorithms beyond annealing such as quantum simulation and variational quantum eigensolvers. A final output of project AVaQus is a blueprint to build a large-scale coherent quantum annealing processor in a follow-up phase.
The goal of the AVaQus project is to develop a quantum annealer prototype of 5 coherent flux-like qubits, with interactions beyond the Ising model and a large connectivity map. This prototype will be used as a demonstrator for several proof-of-principle dynamical control techniques and theoretically study its applicability in larger-scale processors that could lead to a quantum advantage. The annealer prototype will also be used to implement quantum algorithms beyond annealing such as quantum simulation and variational quantum eigensolvers. A final output of project AVaQus is a blueprint to build a large-scale coherent quantum annealing processor in a follow-up phase.
On the hardware side, multiple circuit components have been established that will become part of the final 5-qubit prototype. Among the completed components, a wideband nearly quantum-limited amplifier was produced with a bandwidth spanning several gigaherz and a center frequency which can be tuned over several gigaherz. This amplifier is state-of-the-art in the field and will be necessary for the multi-qubit readout scheme in multi-qubit prototype annealers. At the same time, individual coherent flux qubit devices of low and high impedance were built and characterized as part of a downselection process to determine the most suitable qubit type in larger prototypes. The initial coupled qubit devices have been produced and characterized. These devices will soon be tuned to be operated as coherent quantum annealers.
Parallel to qubit developments, a flexible, scalable cabling technology has been adapted for quantum annealing needs and is ready to be tested with the multi-qubit devices.
On the theory side, a circuit design generating a nonclassical interaction between flux-like qubits was produced. This circuit element will be part of future quantum annealer prototypes to study the effect such interactions, having no classical analogue.
On the software side, in order to study the boundary where classical computation becomes inefficient and a quantum processor would take over, a classical simulator was developed which allows the simulation of noisy quantum systems with reasonable accuracy for qubit numbers well above one hundred. Furthermore, a tool was created to help understanding the effects of hardware noise on a quantum simulation, by calculating the effective model such a noisy simulation would correspond to.
In parallel, a variety of algorithms and simulation protocols have been developed that will be implemented in the final annealing prototypes. These protocols include a sorting algorithm, and a method to engineer thermal states with a quantum annealer.
Finally, we are exploring the properties of the energy spectrum related to the computational capabilities of an annealing device, and in particular we have developed a method for bounding transitions that may destroy the computation process
Parallel to qubit developments, a flexible, scalable cabling technology has been adapted for quantum annealing needs and is ready to be tested with the multi-qubit devices.
On the theory side, a circuit design generating a nonclassical interaction between flux-like qubits was produced. This circuit element will be part of future quantum annealer prototypes to study the effect such interactions, having no classical analogue.
On the software side, in order to study the boundary where classical computation becomes inefficient and a quantum processor would take over, a classical simulator was developed which allows the simulation of noisy quantum systems with reasonable accuracy for qubit numbers well above one hundred. Furthermore, a tool was created to help understanding the effects of hardware noise on a quantum simulation, by calculating the effective model such a noisy simulation would correspond to.
In parallel, a variety of algorithms and simulation protocols have been developed that will be implemented in the final annealing prototypes. These protocols include a sorting algorithm, and a method to engineer thermal states with a quantum annealer.
Finally, we are exploring the properties of the energy spectrum related to the computational capabilities of an annealing device, and in particular we have developed a method for bounding transitions that may destroy the computation process
The main goal of project AVaQus is to produce small-scale coherent quantum annealing prototypes, of both low and high impedance, where anealing and simulation algorithms specifically designed will be executed.
In the remaining part of the project, it is expected that the first coupled qubit annealers will be put into operation, allowing the algorithms and applications developed by the AVaQus partners to be run in these prototypes. With all these devices, it will be possible to characterize the effect of coherence on quantum annealing devices.
The impact of AVaQus will be very high on the industry of quantum computation. The results of AVaQus will provide industrial players with scalable prototypes to build larger-size quantum processors capable of outperforming specific classical algorithms identified within the project. The fundamental results of this project will impact academic laboratories to extend the studies in AVaQus in coherent quantum annealing, thus providing further developments to keep enhancing the capabilities of large-scale coherent quantum annealing processors.
Obtaining a functional quantum processor with the capability to outperform conventional computers in the near term will have a strong societal impact in all the real-world problems it will be able to address. Annealers are particularly suited to optimization problems, which are extremely ubiquitous in our society, such as navigation, scheduling, and portfolio management, among many other relevant areas.
In the remaining part of the project, it is expected that the first coupled qubit annealers will be put into operation, allowing the algorithms and applications developed by the AVaQus partners to be run in these prototypes. With all these devices, it will be possible to characterize the effect of coherence on quantum annealing devices.
The impact of AVaQus will be very high on the industry of quantum computation. The results of AVaQus will provide industrial players with scalable prototypes to build larger-size quantum processors capable of outperforming specific classical algorithms identified within the project. The fundamental results of this project will impact academic laboratories to extend the studies in AVaQus in coherent quantum annealing, thus providing further developments to keep enhancing the capabilities of large-scale coherent quantum annealing processors.
Obtaining a functional quantum processor with the capability to outperform conventional computers in the near term will have a strong societal impact in all the real-world problems it will be able to address. Annealers are particularly suited to optimization problems, which are extremely ubiquitous in our society, such as navigation, scheduling, and portfolio management, among many other relevant areas.