New analog quantum computers to solve previously unsolvable problems

Physicists have created a new type of analog quantum computer that can tackle tough physics problems that even the most powerful digital supercomputers can’t.

New research has been published in nature physics A collaboration of scientists from Stanford University in the US and University College Dublin (UCD) in Ireland has shown that a new type of highly specialized analog computer, whose circuits feature quantum components, can solve problems from the cutting edge of quantum physics that were previously out of reach. When these devices are scaled up, they may be able to shed light on some of the most important unsolved problems in physics.

For example, scientists and engineers have long wanted to gain a better understanding of superconductivity, because of its existence superconducting materials— such as those used in MRI machines, very fast train and energy-efficient long-range power grids – currently only operate at very low temperatures, which limits their wider use. The holy grail of materials science is to find room-temperature superconducting materials that would revolutionize their use in a range of technologies.

Dr Andrew Mitchell is Director of the UCD Center for Engineering, Science and Technology (C-QuEST), a theoretical physicist in the UCD School of Physics and a co-author on the paper.

He said, “Some problems are so complex that even the fastest classical digital computers cannot solve them. Exact simulations of complex quantum materials such as High temperature superconductors A really interesting example – this kind of computation is far beyond current capabilities due to the exponential computing time and memory requirements needed to simulate the properties of real-world models.”

“However, the technological and engineering advances driving the digital revolution have brought with them an unprecedented ability to control matter at the nanoscale. This has enabled us to design specialized analog computers, called ‘quantum simulators’, that solve specific paradigms in quantum physics by remotely by taking advantage of the inherent quantum mechanical properties of their nanoscale components.While we have not yet been able to build a multi-purpose programmable quantum computer with enough power to solve all open problems in physics, what we can do now is to build custom analog devices with quantum components that can solve specific problems in quantum physics. .”

The architecture of these new quantum devices includes hybrid metal-semiconductor components embedded in a nanoelectronic circuit, devised by researchers at Stanford University, UCD and the DOE’s SLAC National Accelerator Laboratory (located at Stanford). The Experimental Nanosciences group at Stanford, led by Professor David Goldhaber-Gordon, built and operated the device, while theory and modeling were done by Dr. Mitchell at UCLA.

“We always make mathematical models that we hope will capture the essence of the phenomena we are interested in, but even if we think they are true they are often not solvable in a reasonable amount of time,” said Professor Goldhaber-Gordon, a researcher at the Stanford Institute for Materials and Energy Sciences.

With a quantum simulator, Professor Goldhaber-Gordon said, “We have these knobs for turning that no one has had before.”

Why analog?

The basic idea of ​​these analog devices, Goldhaber-Gordon said, is to build some kind of hardware analogy to the problem you want to solve, rather than writing some computer code for a programmable digital computer. For example, suppose you wanted to predict the movement of planets in the night sky and the timing of eclipses. You can do this by building a mechanical model of the solar system, where someone turns a crank, and the rotating meshing gears represent the motion of the moon and planets.

In fact, such a mechanism was discovered in an ancient shipwreck off the coast of a Greek island dating back more than 2,000 years. This device can be thought of as a very early analog computer.

Not to be sniffed, analog machines were used until the late 20th century for mathematical calculations that would have been too difficult for the most advanced digital computers of the time.

But to solve it Quantum physics Problems, devices need to involve quantum components. It includes the architecture of the new quantum simulator electronic circuits With nanocomponents whose properties are governed by the laws of quantum mechanics. Importantly, many of these components can be synthesized, with each one behaving essentially identical to the others.

This is critical to analog simulations of quantum materials, where each of the electronic components in a circuit is a proxy for simulating an atom, behaving like an ‘artificial atom’. Just as different atoms of the same type in matter behave identically, so should the different electronic components of an analog computer.

The new design therefore provides a unique path for scaling the technology from individual modules to large networks capable of simulating massive quantum matter. Moreover, the researchers showed that new quantum interactions can be engineered into such devices. The work is a step towards developing a new generation of scalable, solid-state analog quantum computers.

Quantum beginnings

To demonstrate the power of analog quantum computation using their new Quantum Simulator platform, the researchers first studied a simple circuit involving two quantum components coupled together.

The device simulates a model of two atoms bound together by a strange quantum interaction. By adjusting the electrical voltages, the researchers were able to produce a new state of matter in which electrons appear to have only one part of their usual electrical charge – so-called “Z3 parafermions”. These elusive states have been proposed as the basis for future topological quantum computation, but have not previously been generated in vitro in an electronic device.

“By scaling a quantum simulator from two components to many nanoscale components, we hope to be able to design more complex systems that current computers simply cannot handle,” said Dr. Mitchell. “This may be the first step to finally unraveling some of the most puzzling mysteries of our quantum realm.”