A powerful new form of calculation can help scientists design new types of materials for nanoelectronics, allow airlines to solve complex logistical problems to ensure that flights are delivered on time, and tackle congestion to keep up free movement of vehicles on busy roads.
While modern digital computers are capable of impressive computing, there are some issues that even the most advanced supercomputers can do. But researchers believe that new computers that are involved in the power of quantum mechanics that manage the strange behavior of microscopic particles such as bosons, farms and anions can handle these problems in seconds.
The construction of generic quantum computers has proved extremely difficult, and only a few expensive machines are currently being developed.
Some scientists instead use another approach by building computing systems, known as analog quantum simulators, in an attempt to find a way to some of the answers quantum computers promise to provide.
These simulators are designed to examine the specific properties of quantum physics by modeling how the smallest particles in the universe can behave. This in turn can be applied to solve complex problems in a wider world that are currently impossible to work or can take a lifetime to do this with the help of classic computers.
"The analogy I really like is that analogue quantum simulators are a bit like an aerodynamic tunnel," said Professor Andrew Daley, a physicist at Strathclyde University, UK, and a member of the PASQuanS project. A few decades ago, it was impossible to simulate airflow on a computer, so instead a large-scale model would be built and placed in an aerodynamic tunnel.
But with analog quantum simulation, scaling goes in another way – instead of making a smaller version, you make it bigger. This makes it more controllable and so it's easier to learn the details of how something can work.
By joining a team of researchers from across Europe, the project is trying to build some of the most powerful analog quantum simulators to date using atoms and ions like their large subatomic particle models.
For example, ultra-chalky atoms that are cooled to just a few degrees above absolute zero can be hung in a grid formed by laser light to simulate how electrons can move in a crystal. So far, the most advanced quantum simulators use about 100 ultrahigh atoms or up to 20 ions in their models, but the team hopes to strengthen their systems to have more than 1000 atoms and up to 50 ions.
This could push the power of these simulators far beyond what is possible with the classical calculation in much shorter terms than would be possible by building a common quantum computer, Prof. Daley says.
A major challenge is to make simulators more controllable and programmable. Researchers participating in the project are developing new techniques for controlling atoms, such as capturing them with laser tweezers, exciting selected atoms in high-energy states, or moving them to interact in different ways.
"The programmable bit is all that makes these systems very controllable, in a well-calibrated way, at the level of individual lattice sites, individual ions or individual atoms," Prof. Daley says.
While these simulators can help physicians solve the questions about particle behavior taxation in quantum systems, they can also be used to solve bigger problems in the real world.
Quantum resurfacing algorithms, for example, use subtle quantum physics in which subatomic particles, atoms and larger molecules can find the path of least resistance to changing energy states. This can be compared to trying to roll the ball up a hill to reach a deeper valley on the other side – if the ball is not given enough push, there will be no energy to reach the top of the hill and just roll back. For comparison, quantum particles can bypass the energy peaks they have to overcome by simply passing through them.
This ability to find low energy states more easily means that quantum annealing can be used to find ways to optimize complex traffic networks or complex logistics chains.
"We can take some other problem and map it to the interaction between atoms or ions," Prof. Daley says. "Then we can start asking questions to find the lowest possible energy configuration.
Major companies such as Airbus, Total, Bosch, Electricité de France (EDF) and Siemens have already shown interest in exploring this approach. Researchers from companies are working on the project in an attempt to find potential applications that can be applied to their commercial operations.
On airplanes, for example, it can be used to ensure that airplanes and crews of airlines are in the right place to allow flights to run smoothly.
It can also be used to quickly model the best way to redirect traffic on busy roads to avoid clogging and reduce pollution.
"We created a forum for end users to get specific ideas about the type of problems that can be realized on analog quantum simulation platforms," said Professor Daly. "These are major issues that are particularly interesting to the industry so we can imitate our systems."
The power of quantum simulators goes beyond finding ways to optimize processes. Prof. Daley and colleagues say that one of the first applications of their quantum simulators will be to help design new materials, including nanoelectronics and superconductors.
This is something the Qombs project also pursues by creating an analogue quantum simulation to create a new generation of material that can produce highly adjustable infrared lasers. The wavelength – or color – of modern lasers is determined by the elements in the diode used to generate the light.
But by growing crystals that contain different layers of metals such as aluminum, gallium and arsenic, the researchers behind the project want to create semiconductor materials that can produce laser light with a wavelength that would otherwise be impossible. These devices are known as quantum cascade lasers.
"We use quantum simulations to optimize and get new features that will improve the work that is possible with quantum cascading lasers today," said Dr. Francesco Capelli, a researcher at the National Optics Institute in Florence, Italy. by the Qombs team.
By simulating how electrons and photons can behave in different structures and concentrations of metals, the team hopes to better control the wavelength of the light produced by the devices.
If it succeeds, it can lead to devices that can produce light with extremely long wavelengths that stretch in mid and far infrared light, something that is currently unattainable.
"They can be used in communication as light is not absorbed by the gases in the atmosphere at these wavelengths," says Dr. Kapeli. "Not only is the atmosphere transparent, but the dispersion due to moisture and dust is reduced compared to the visible lasers."
Adjusting lasers to specific wavelengths can also allow them to be used in sensors to detect specific gases such as pollutants or other harmful substances.
The quantum cascade laser tuned to emit light of the exact wavelength absorbed, for example, by nitrogen dioxide can be used to accurately measure gas levels in urban areas.
"Designing semiconductor crystals with such properties will never be possible on classical computers," says Dr. Capelly.
The power of quantum computing
In traditional computers, information is contained in binary digits or bits that contain a single value of 1 or 0.
In quantum systems, subatomic particles can exist not only in binary 1 or 0 states, but they have multiple combinations of 1 and 0 simultaneously to form a "cubite". Because the cube can be 1, 0, or 1 and 0 all at once, it means that much more can be done simultaneously.
Even stranger, pairs of cubits can also get entangled, so when the state of one changes, the other changes instantly with it, even if they are separated by long distances. This mysterious phenomenon exponentially increases the ability of the quantum machine to pass the numbers.
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restored on June 17, 2019
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