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**Quantum computers will now have help tackling the central problem in their performance – noise.**

Joel Wallman, a researcher at the Institute for Quantum Computing (IQC) and assistant professor of applied mathematics at the University of Waterloo has developed a protocol that will help deal with the issue of noise in quantum computers so that they can tackle more complex problems.

“The intrinsic noise in quantum computers makes their output unreliable,” said Wallman, co-founder of Quantum Benchmark, a startup spun out of IQC. “So any problem that we know how to solve on a quantum computer can be solved better on conventional computers. To deliver quantum computers that can do something useful, we need to make larger quantum computers and work out how to accurately control them.”

Wallman, together with Robin Harper and Steve Flammia of the University of Sydney, has developed a new protocol that works on large systems – quantum computers running on many qubits (the quantum version of a classical computer’s binary bit)– that lets researchers characterize quantum noise across the qubits reliably and efficiently.

Prior to this work, researchers ran error assessment protocols that could only detect errors on a small subset of the qubits. The new method returns an estimate of the effective noise and can detect error correlations within arbitrary sets of qubits.

“The reason this protocol is so important is that if noise in systems don’t act locally, existing error correction and mitigation techniques just don’t work,” says Wallman. “And the data we obtained demonstrated that such nonlocal errors exist in real quantum computers.”

Wallman’s research team at the University of Waterloo and Quantum Benchmark is currently furthering the technique to characterize and suppress errors in specific data operations.

Efficient learning of quantum noise by Harper, Flammia, and Wallman was published in Nature Physics on August 10, 2020.

Tools based on the method are included in True-Q, the world-leading error characterization software from Quantum Benchmark.

**Here Is The Abstract From The Research Paper:**

Noise is the central obstacle to building large-scale quantum computers. Quantum systems with sufficiently uncorrelated and weak noise could be used to solve computational problems that are intractable with current digital computers. There has been substantial progress towards engineering such systems1,2,3,4,5,6,7,8. However, continued progress depends on the ability to characterize quantum noise reliably and efficiently with high precision9. Here, we describe such a protocol and report its experimental implementation on a 14-qubit superconducting quantum architecture. The method returns an estimate of the effective noise and can detect correlations within arbitrary sets of qubits. We show how to construct a quantum noise correlation matrix allowing the easy visualization of correlations between all pairs of qubits, enabling the discovery of long-range two-qubit correlations in the 14-qubit device that had not previously been detected. Our results are the first implementation of a provably rigorous and comprehensive diagnostic protocol capable of being run on state-of-the-art devices and beyond. These results pave the way for noise metrology in next-generation quantum devices, calibration in the presence of crosstalk, bespoke quantum error-correcting codes10 and customized fault-tolerance protocols11 that can greatly reduce the overhead in a quantum computation.

**(If the above research is somewhat overwhelming, you're not alone. Below is an article which helps explain the importance of this research.)**

**What Is Quantum Computing? A Super-Easy Explanation For Anyone**

By Bernard Marr – Forbes Magazine

It’s fascinating to think about the power in our pocket—today’s smartphones have the computing power of a military computer from 50 years ago that was the size of an entire room. However, even with the phenomenal strides we made in technology and classical computers since the onset of the computer revolution, there remain problems that classical computers just can’t solve. Many believe quantum computers are the answer.

**The Limits of Classical Computers**

Now that we have made the switching and memory units of computers, known as transistors, almost as small as an atom, we need to find an entirely new way of thinking about and building computers. Even though a classical computer helps us do many amazing things, “under the hood” it’s really just a calculator that uses a sequence of bits—values of 0 and 1 to represent two states (think on and off switch) to makes sense of and decisions about the data we input following a prearranged set of instructions. Quantum computers are not intended to replace classical computers, they are expected to be a different tool we will use to solve complex problems that are beyond the capabilities of a classical computer.

Basically, as we are entering a big data world in which the information we need to store grows, there is a need for more ones and zeros and transistors to process it. For the most part classical computers are limited to doing one thing at a time, so the more complex the problem, the longer it takes. A problem that requires more power and time than today’s computers can accommodate is called an intractable problem. These are the problems that quantum computers are predicted to solve.

**The Power of Quantum Computers**

When you enter the world of atomic and subatomic particles, things begin to behave in unexpected ways. In fact, these particles can exist in more than one state at a time. It’s this ability that quantum computers take advantage of.

Instead of bits, which conventional computers use, a quantum computer uses quantum bits—known as qubits. To illustrate the difference, imagine a sphere. A bit can be at either of the two poles of the sphere, but a qubit can exist at any point on the sphere. So, this means that a computer using qubits can store an enormous amount of information and uses less energy doing so than a classical computer. By entering into this quantum area of computing where the traditional laws of physics no longer apply, we will be able to create processors that are significantly faster (a million or more times) than the ones we use today. Sounds fantastic, but the challenge is that quantum computing is also incredibly complex.

The pressure is on the computer industry to find ways to make computing more efficient, since we reached the limits of energy efficiency using classical methods. By 2040, according to a report by the Semiconductor Industry Association, we will no longer have the capability to power all of the machines around the world. That’s precisely why the computer industry is racing to make quantum computers work on a commercial scale. No small feat, but one that will pay extraordinary dividends.

**How our world will change with quantum computing**

It’s difficult to predict how quantum computing will change our world simply because there will be applications in all industries. We’re venturing into an entirely new realm of physics and there will be solutions and uses we have never even thought of yet. But when you consider how much classical computers revolutionized our world with a relatively simple use of bits and two options of 0 or 1, you can imagine the extraordinary possibilities when you have the processing power of qubits that can perform millions of calculations at the same moment.

What we do know is that it will be game-changing for every industry and will have a huge impact in the way we do business, invent new medicine and materials, safeguard our data, explore space, and predict weather events and climate change. It’s no coincidence that some of the world’s most influential companies such as IBM and Google and the world’s governments are investing in quantum computing technology. They are expecting quantum computing to change our world because it will allow us to solve problems and experience efficiencies that aren’t possible today. In another post, I dig deeper into how quantum computing will change our world.

**How Could Quatum Computing Change the World?**

**If TRUE, the following paragraph pretty much puts it into focus:**

The Financial Times asserted in an article they published that a quantum computer could perform a calculation “in three minutes and 20 seconds that would take today’s most advanced classical computer … approximately 10,000 years”.

As someone once said of the book of Genesis, this would be “important if true”. A more mischievous thought was: how would the researchers check that the quantum machine’s calculation was correct?