# New algorithm optimizes quantum computing problem-solving

April 10, 2019Tohoku University researchers have developed an algorithm that enhances the ability of a Canadian-designed quantum computer to more efficiently find the best solution for complicated problems, according to a study published in the journal

*Scientific Reports*.

Quantum computing takes advantage of the ability of subatomic particles to exist in more than one state at the same time. It is expected to take modern-day computing to the next level by enabling the processing of more information in less time.

The D-Wave quantum annealer, developed by a Canadian company that claims it sells the world's first commercially available quantum computers, employs the concepts of quantum physics to solve 'combinatorial optimization problems.'. A typical example of this sort of problem asks the question: "Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city and returns to the origin city?" Businesses and industries face a large range of similarly complex problems in which they want to find the optimal solution among many possible ones using the least amount of resources.

Ph. D candidate Shuntaro Okada and information scientist Masayuki Ohzeki of Japan's Tohoku University collaborated with global automotive components manufacturer Denso Corporation and other colleagues to develop an algorithm that improves the D-Wave quantum annealer's ability to solve combinatorial optimization problems.

The algorithm works by partitioning an original large problem into a group of subproblems. The D-Wave annealer then iteratively optimizes each subproblem to eventually solve the original larger one. The Tohoku University algorithm improves on another algorithm using the same concept by allowing the use of larger subproblems, ultimately leading to the arrival at more optimal solutions more efficiently.

"The proposed algorithm is also applicable to the future version of the D-Wave quantum annealer, which contains many more qubits," says Ohzeki. Qubits, or quantum bits, form the basic unit in quantum computing. "As the number of qubits mounted in the D-Wave quantum annealer increases, we will be able to obtain even better solutions," he says.

The team next aims to assess the utility of their algorithm for various optimization problems.

-end-

Tohoku University

**Related Quantum Computing Articles:**

Diversity may be key to reducing errors in quantum computing

In quantum computing, as in team building, a little diversity can help get the job done better, computer scientists have discovered.

In quantum computing, as in team building, a little diversity can help get the job done better, computer scientists have discovered.

'Valley states' in this 2D material could potentially be used for quantum computing

New research on 2-dimensional tungsten disulfide (WS2) could open the door to advances in quantum computing.

New research on 2-dimensional tungsten disulfide (WS2) could open the door to advances in quantum computing.

Sound of the future: A new analog to quantum computing

In a paper published in Nature Research's journal, Communications Physics, researchers in the University of Arizona Department of Materials Science and Engineering have demonstrated the possibility for acoustic waves in a classical environment to do the work of quantum information processing without the time limitations and fragility.

In a paper published in Nature Research's journal, Communications Physics, researchers in the University of Arizona Department of Materials Science and Engineering have demonstrated the possibility for acoustic waves in a classical environment to do the work of quantum information processing without the time limitations and fragility.

Imaging of exotic quantum particles as building blocks for quantum computing

Researchers have imaged an exotic quantum particle -- called a Majorana fermion -- that can be used as a building block for future qubits and eventually the realization of quantum computers.

Researchers have imaged an exotic quantum particle -- called a Majorana fermion -- that can be used as a building block for future qubits and eventually the realization of quantum computers.

Virginia Tech researchers lead breakthrough in quantum computing

A team of Virginia Tech chemistry and physics researchers have advanced quantum simulation by devising an algorithm that can more efficiently calculate the properties of molecules on a noisy quantum computer.

A team of Virginia Tech chemistry and physics researchers have advanced quantum simulation by devising an algorithm that can more efficiently calculate the properties of molecules on a noisy quantum computer.

Limitation exposed in promising quantum computing material

Physicists have theorized that a new type of material, called a three-dimensional (3-D) topological insulator (TI), could be a candidate to create qubits for quantum computing due to its special properties.

Physicists have theorized that a new type of material, called a three-dimensional (3-D) topological insulator (TI), could be a candidate to create qubits for quantum computing due to its special properties.

New material shows high potential for quantum computing

A joint team of scientists at the University of California, Riverside, and the Massachusetts Institute of Technology is getting closer to confirming the existence of an exotic quantum particle called Majorana fermion, crucial for fault-tolerant quantum computing -- the kind of quantum computing that addresses errors during its operation.

A joint team of scientists at the University of California, Riverside, and the Massachusetts Institute of Technology is getting closer to confirming the existence of an exotic quantum particle called Majorana fermion, crucial for fault-tolerant quantum computing -- the kind of quantum computing that addresses errors during its operation.

A sound idea: a step towards quantum computing

Researchers at the University of Tsukuba and the University of Pittsburgh have developed a new method for using lasers to create tiny lattice waves inside silicon crystals that can encode quantum information.

Researchers at the University of Tsukuba and the University of Pittsburgh have developed a new method for using lasers to create tiny lattice waves inside silicon crystals that can encode quantum information.

Quantum computing boost from vapour stabilising technique

A technique to stabilise alkali metal vapour density using gold nanoparticles, so electrons can be accessed for applications including quantum computing, atom cooling and precision measurements, has been patented by scientists at the University of Bath.

A technique to stabilise alkali metal vapour density using gold nanoparticles, so electrons can be accessed for applications including quantum computing, atom cooling and precision measurements, has been patented by scientists at the University of Bath.

Quantum cloud computing with self-check

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

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

## Top Science Podcasts

We have hand picked the**top science podcasts of 2019**.

**Now Playing: TED Radio Hour**

**Risk**

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.

**Now Playing: Science for the People**

**#540 Specialize? Or Generalize?**

Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".

**Now Playing: Radiolab**

**Dolly Parton's America: Neon Moss**

Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.