#### With a quantum coprocessor in the cloud, physicists from Innsbruck open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics.

Groups led by Rainer Blatt and Peter Zoller report in Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists first simulated the spontaneous formation of a pair of elementary particles with a digital quantum computer at the University of Innsbruck. Due to the error rate, however, more complex simulations would require a large number of quantum bits that are not yet available in today’s quantum computers. The analog simulation of quantum systems in a quantum computer also has narrow limits. Using a new method, researchers around Christian Kokail, Christine Maier und Rick van Bijnen at the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences have now surpassed these limits. They use a programmable ion trap quantum computer with 20 quantum bits as a quantum coprocessor, in which quantum mechanical calculations that reach the limits of classical computers are outsourced. “We use the best features of both technologies,” explains experimental physicist Christine Maier. “The quantum simulator takes over the computationally complex quantum problems and the classical computer solves the remaining tasks.”

##### Toolbox for Quantum Modelers

The scientists use the variational method known from theoretical physics, but apply it on their quantum experiment. „The advantage of this method lies in the fact that we can use the quantum simulator as a quantum resource that is independent of the problem under investigation,“ explains Rick van Bijnen. „In this way we can simulate much more complex problems.“ A simple comparison shows the difference: an analog quantum simulator is like a doll’s house, it represents reality. The programmable variational quantum simulator, on the other hand, offers individual building blocks with which many different houses can be built. In quantum simulators, these building blocks are entanglement gates and single spin rotations. With a classical computer, this set of knobs is tuned until the intended quantum state is reached. For this the physicists have developed a sophisticated optimization algorithm that in about 100,000 requests of the quantum coprocessor by the classical computer leads to the result. Coupled with extremely fast measurement cycles of the quantum experiment, the simulator at IQOQI Innsbruck becomes enormously powerful. For the first time, the physicists have simulated the spontaneous creation and destruction of pairs of elementary particles in a vacuum on 20 quantum bits. Since the new method is very efficient, it can also be used on even larger quantum simulators. The Innsbruck researchers plan to build a quantum simulator with up to 50 ions in the near future. This opens up interesting perspectives for further investigations of solid-state models and high-energy physics problems.

##### Built-in Self-Check

A previously unsolved problem in complex quantum simulations is the verification of the simulation results. “Such calculations can hardly or not at all be checked using classical computers. So how do we check whether the quantum system delivers the right result,” asks the theoretical physicist Christian Kokail. “We have solved this question for the first time by making additional measurements in the quantum system. Based on the results, the quantum machine assesses the quality of the simulation,” explains Kokail. Such a verification mechanism is the prerequisite for even more complex quantum simulations, because the necessary number of quantum bits increases sharply. “We can still test the simulation on 20 quantum bits on a classical computer, but with more complex simulations this is simply no longer possible,” says Rick van Bijnen. “In our study, the quantum experiment was even faster than the control simulation on the PC. In the end, we had to take it out of the race in order not to slow down the experiment,” says the physicist.

Innsbruck Quantum Cloud

This research achievement is based on the unique collaboration between experiment and theory at the Innsbruck quantum research center. The expertise from years of experimental quantum research meets innovative theoretical ideas in Tyrol, Austria. Together, this leads to results that are recognized worldwide and establishes an internationally leading position of Innsbruck’s quantum research. “15 years of very hard work have gone into this experiment,” emphasizes experimental physicist Rainer Blatt. “It is very nice to see that this is now bearing such beautiful fruit.” The theoretical physicist Peter Zoller adds: “We in Innsbruck are not only leaders in the number of available quantum bits, but have now also advanced into the field of programmable quantum simulation and were able to demonstrate for the first time the self-verification of a quantum processor. With this new approach, we are bringing the simulation of everyday quantum problems within reach.”

Learn more: Quantum Cloud Computing with Self-Check

##### The Latest on: Quantum simulator

[google_news title=”” keyword=”quantum simulator” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]

*via Google News*

##### The Latest on: Quantum simulator

- Page 2: Quantum recordson May 18, 2024 at 7:38 pm
But on correspondingly thick iron, you can still outdo this classically with quantum simulation, at least in Jülich. All you need is 2048 Nvidia GPUs with A100 tensor cores and a simulator for 40 ...

- International research team uses wavefunction matching to solve quantum many-body problemson May 16, 2024 at 12:03 pm
One such method is quantum Monte Carlo simulations. In quantum Monte Carlo simulations, quantities are computed using random or stochastic processes. While quantum Monte Carlo simulations can be ...

- Second House of Quantum opens in Delfton May 16, 2024 at 9:45 am
House of Quantum is part of the Quantum Delta NL initiative and is growing rapidly, providing startups with offices and plug-and-play labs ...

- Coupling quantum mechanical simulations and AI paves way for screening new superconductorson May 16, 2024 at 7:09 am
Superconductors are materials that conduct electricity without resistance and are essential for several technological advancements, which include medical imaging and energy-efficient technology.

- 7 Quality Quantum Computing Stocks to Buy Before Juneon May 16, 2024 at 4:00 am
InvestorPlace - Stock Market News, Stock Advice & Trading Tips Growth stock investors should be considering quantum computing stocks to buy ...

- New method of wavefunction matching helps solve quantum many-body problemson May 15, 2024 at 10:45 am
Strongly interacting systems play an important role in quantum physics and quantum chemistry. Stochastic methods such as Monte Carlo simulations are a proven method for investigating such systems.

- Nvidia launches quantum computer centers with CUDA-Q platformon May 13, 2024 at 6:00 am
Nvidia will accelerate quantum computing efforts at supercomputing centers around the world with the open-source Nvidia CUDA-Q platform.

- Quantum simulators solve physics puzzles with colored dotson May 8, 2024 at 10:22 am
By analyzing images made of colored dots created by quantum simulators, ETH researchers have studied a special kind of magnetism. In the future this method could also be used to solve other physics ...

- Physicist achieve milestone in quantum simulation with circular Rydberg qubitson May 8, 2024 at 6:35 am
A team of researchers from the 5th Institute of Physics at the University of Stuttgart is making important progress in the field of quantum simulation and quantum computing based on Rydberg atoms by ...

- Chinese scientists achieve significant advancement in quantum simulation technologyon May 6, 2024 at 6:26 pm
BEIJING -- A Chinese research team has realized the fractional quantum anomalous Hall state of photons for the first time by using an independently developed quantum experimental system, the ...

*via Bing News*