Three Truths and the Advent of Hybrid Quantum Computing

Murray Thom
Jun 25, 2019 · 6 min read

Quantum computing is getting a lot of attention. Whether it’s the possibility of discovering new life-saving drugs, advances in materials science, or improvements to information security, the headlines are compelling. But dig deeper, and the questions businesses are asking are elemental: what is quantum computing? How do I determine if quantum computing can help my business? How do I think about incorporating quantum computing into my technology roadmap? How do I create the right teams? And how much will my existing applications need to change? Like cloud computing ten years ago, we are at the very beginning.

But how to begin? Quantum-classical hybrid algorithms may just be the best first step.

Hybrid is the way to quantum computing

Today we’re announcing a new path to quantum computing — D-Wave Hybrid™. At its most basic, D-Wave Hybrid is a simple, open-source hybrid workflow platform for building and running quantum-classical applications. We think of it as an on-ramp of sorts and we’re excited to share it.

“Quantum applications will always and only be hybrid.”

With D-Wave Hybrid, you can start with the algorithms you already have and gradually introduce quantum to your workflows where it makes sense for your business, while keeping intact what works well. You don’t need to be a physicist to benefit from quantum computing. D-Wave Hybrid is now part of the Ocean™ SDK, D-Wave’s open-source Python toolset, which means application developers can work in a familiar programming paradigm using tools that abstract away many of the low-level details. And because we offer access to our quantum systems in the cloud via the Leap™ cloud service, the resources you need are immediately available.

So why do we need quantum-classical hybrid algorithms?

The three truths (that likely no one has mentioned)

Truth #1: Don’t let anyone tell you otherwise, quantum applications will always and only be hybrid. Quantum and classical computing technologies have complementary strengths that benefit applications. Consider that while jet airplanes transformed the way we travel long distances, we still need vehicles that take us to our front door. Likewise, we will still need our laptops and familiar programming languages in the era of quantum applications.

Truth #2: Customers (you!) value results above all, and it is results that provide technology value, not the other way around. Quantum mechanics are mysterious, but quantum computing is practical because it can harness quantum mechanics to do useful work with power and efficiency that is not possible for classical computers. Much like any other shiny new technology that has come across your desk, your business needs to see benefit from the investment. Whether in the early days as you find new pathways to hard problems or in the pursuit of longer-term business value, quantum computing is most beneficial when it lives out of the lab and starts to solve real problems. It’s our job to build useful quantum technologies to help benefit your business, not to mire you in the mechanics of it all.

Truth #3: There is an important role for quantum computing that has been left vacant by classical systems. As powerful as today’s classical computing technologies may be, there is an emerging frontier of applications that require new resources — quantum resources — to meet the demands of entrepreneurs with wild new ideas and businesses in competitive markets. Today’s announcement of D-Wave Hybrid is a clear step in that direction.

Ok, but what is quantum-classical hybrid?

Quantum-classical hybrid is the use of both classical and quantum resources to solve problems. A hybrid approach allows developers to exploit the powers of both, today, and reap the benefits of the ongoing acceleration in quantum-computer development tomorrow. As the size of the processors grow, quantum computers promise to provide unrivaled performance at some types of tasks, such as solving certain hard optimization problems.

An example of the benefit of using a hybrid approach can be seen in how Recruit Communications uses quantum computing to optimize ad placement in its prototype application that inputs data from mobile phones and databases. While the quantum computer handles the hard problem of optimizing click-through-rate prediction, classical resources do everything else — from getting user data and communicating with servers, to displaying results. This example of a quantum-classical hybrid workflow is similar to how central processing units (CPUs) in laptops outsource compute-intensive graphics-display processing to a graphics processing unit (GPU). As every business knows, since Ford’s first automobile plant, allocating the tasks of a complex job to specialized resources is an unbeatable strategy.

D-Wave Hybrid provides developers with a Python framework for building a variety of flexible hybrid workflows so quantum and classical resources can be used in parallel to find the optimal solution to your business problem. Other hybrid workflows might use classical resources to find a problem’s hard core and send that to the QPU or break a large problem into smaller pieces that can be solved on a QPU and then recombined.

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Next steps

Assess your applications. Begin by searching for bottlenecks in your applications, places where they spend a lot of time solving problems or where they return unsatisfactory results. These applications may be workhorses, but the availability of new data, new computers, or new sensing technology may make them more complex and slower than before.

Ask these key questions. If you answer Yes to some or all of the questions below, your application may benefit from adding quantum computation.

  • Does your application make binary judgements or answers to a question that are either True or False? (E.g., Did each task meet its deadline? Did network nodes experience failures? Did loans go into default? Did neurons activate? Did the crew make it to the flight?)
  • Are there relationships and correlations between the inputs? (E.g., Does one missed deadline affect other tasks? Does a failed network node change the load on other nodes? Does a defaulted loan affect the risk to other loans? Which other neurons received the signal through their synapses? Is the crew required for other flights?)

Frame your problem in a form that quantum computers can solve. For quantum computing, as for classical, solving a problem requires that it be formulated in a way the computer and its software understand. The D-Wave quantum computer accepts a problem formulated as a binary quadratic model (BQM), a form of cost function that it solves by minimizing energy. A BQM problem is simply a collection of binary variables with associated linear and quadratic biases. Several examples are available in the D-Wave Ocean documentation.

Deconstruct the problem. Find good solutions to your problem using the different strengths afforded by both quantum and classical computing resources. D-Wave Hybrid provides out-of-the-box hybrid workflows to get you started. As a first step, try Kerberos, a workflow in which D-Wave Hybrid coordinates the work between your laptop’s CPU and the quantum computer to find solutions, such as finding a valid map coloring. You can later use the framework to optimize a hybrid workflow best-suited for your particular problem.

Sign up for Leap to get access to real-time quantum computer. Through Leap, D-Wave’s quantum cloud service, you can try a live quantum computer for free and access a wealth of resources in the Quantum Application Environment (QAE) to get started. Run our demos that introduce the programming model and the types of problems that the quantum computer is well-suited to solve. Try our interactive Jupyter Notebooks that teach you to program. Join a community of like-minded developers.

Download the Ocean SDK and start coding. D-Wave Hybrid is part of the Ocean SDK, the open-source toolset for programming the D-Wave quantum computer. It’s available on GitHub.

The probabilities are endless.

We invite you to experience real, practical quantum computing. With D-Wave Hybrid, we’ve built a new pathway. We welcome you to join a growing group of developers and forward-thinking businesses who are already getting started and, in the process, building the future.


The Quantum Computing Company

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