### Intelligent Machines

# Europe Unveils Its Vision for a Quantum Future

## The race to develop the next generation of quantum technology just got hotter.

The race to conquer the quantum world is among the most fiercely competitive in technology. China and the U.S. have both invested billions in developing new ways to exploit the strange laws of physics that quantum effects give access to. The promise is a new era of computing and communication and, of course, undreamed-of riches.

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In all the excitement, one part of the world is being left behind. Europe has a rich history of innovation in quantum physics but has begun to fall behind its global competitors in recent years.

That’s why the European Commission announced in 2016 that it was investing one billion euros in a research effort known as the Quantum Technology Flagship. The goal for this project is to develop four technologies: quantum communication, quantum simulation, quantum computing, and quantum sensing. After almost two years, how is it going?

Today we get a glimpse thanks to the publication of the European Quantum Technologies Roadmap, an updated version of the document that sets out the project’s goals over the next 10 years. In particular, it outlines two emerging areas that have received less interest in other parts of the world—quantum software and quantum control. These could have significant implications for the future of European quantum technologies.

The document begins by outlining the areas of focus. The first, quantum communication, offers the ability to send data from one location to another with complete privacy, guaranteed by the laws of physics. That is becoming increasingly important because another technology—quantum computing—will soon be able to break the encryption commonly used today. Secure communication is one of the foundations of modern society, enabling e-commerce and ensuring the privacy of business, government, and military communications.

The problem is that existing quantum communication systems are expensive and complex to manage and run. The next stage in the evolution of these systems is to make them much more manageable.

The commission says this is imminent: “Foreseeable within the next three years is the development of autonomous [quantum communication] systems over metropolitan distances that will address low deployment costs, high secure key rates (> 10Mbps) and multiplexing.”

Another problem is that quantum communication only works over point-to-point connections of about 100 kilometers. So researchers are also working on quantum routers that can send the signals much farther. “In 6 years, we will likely see [quantum communication systems] in test-bed networks, demonstrating long distances via trusted nodes, high altitude platform systems or satellites, as well as multi-node or switchable intra-city networks, all of which will require large-scale infrastructure projects to be initiated,” says the report.

The next area is quantum computation, which uses quantum processes to generate impressive data processing performance. This has been possible on the scale of just a few quantum bits, or qubits, for some years. The challenge today is to scale quantum computers to 100 qubits or more.

This road map outlines five potential ways of doing this, using systems that store and process quantum information in different ways. These include storing the information in ions trapped in a magnetic field or in atomic nuclei embedded in silicon or carbon, in the flow of current through tiny superconducting circuits, or in photons traveling through photonic circuits.

The commission clearly expects large-scale quantum processing using one or more of these technologies within five to 10 years. Whether this will be done in Europe first is much less clear.

Quantum simulation is the third area of investment. Simulating complex quantum properties on an ordinary computer is close to impossible. But quantum systems can be made to simulate aspects of other quantum systems more or less perfectly.

Physicists are toying with various ways of doing this. The basic idea is to find a quantum system that is well understood, and easy to manipulate and measure, and then use that to simulate a system that is hard to manipulate and measure.

The well-understood systems include ultra-cold atoms and molecules, ions trapped in magnetic fields, and superconducting circuits. The more complex systems that physicists want to understand occur in high-energy physics, in cosmology, in statistical physics, and even in biology, where quantum processes seem to play a role in energy transfer. The promise is that quantum simulation can provide insights into all these areas.

But there are significant challenges. These include finding interesting systems that can be simulated with existing techniques and designing an appropriate experiment to do this. On top of this, physicists must find ways to be sure that the system has correctly performed the simulation.

Just how much of this will be possible within the next 10 years isn’t yet clear.

The fourth area of interest is quantum sensing and metrology. The idea here is that if we want to exploit the quantum world, we have to be able to measure and sense it. That means measuring the universe at the scale of atoms and photons over appropriately short time scales.

Physicists have a wide variety of tools for doing this, but they all need improving. So quantum clocks must be made more precise, atomic sensors must be made more sensitive, and optomechanical sensors need to be made more capable.

The road map ends with a discussion of two new areas of interest. The first is quantum control: the ability to manipulate quantum systems using external electromagnetic fields or forces. “The objective of quantum optimal control is to devise and implement shapes of pulses of external fields or sequences of such pulses, that reach a given task in a quantum system in the best possible way,” it says.

In other words, this is about nudging quantum systems with radio waves and laser beams to make them behave in specific ways. The expectation is that this kind of precise control of quantum systems will enable large-scale quantum computation and simulation, among other things.

The second of these new areas is the development of quantum software, which is much harder to develop than ordinary software because qubits can exist as both *0*s and *1*s at the same time. That means several qubits can carry out many calculations in parallel, which is why quantum computers are so hugely powerful.

But extracting the answer from these calculations is difficult. And that makes quantum algorithms hugely fragile.

The potential is that quantum algorithms can dramatically outperform classical computations. But actually finding algorithms that can do this is tricky. This software will need to work on the scale of both computers and entire networks. Advancing in this area may provide a way for Europe to leapfrog competitors who have an advantage in hardware development.

One of the most exciting problems is developing a theory of quantum information. The classical theory of information developed in the 1940s and ’50s by the mathematician and engineer Claude Shannon has become the foundation of modern computing and communication. A similarly powerful theory for quantum information eludes theorists, but developing one is an important goal in Europe. Much will depend on the outcome.

If this road map is an accurate summary of Europe’s approach to the development of quantum technologies, its global rivals will hardly be quaking in their boots. For the most part, the plan lacks ambition relative to work elsewhere. China, for example, already has a satellite in orbit capable of quantum communication with the ground, and this is the envy of quantum community the world over.

The exceptions are in the areas of quantum control and quantum software. These are enabling technologies with broad applications in the quantum world and could provide an important springboard for Europe.

One big unknown is the role of industry in the future of quantum technologies. Europe is desperate to partner with companies such as Google, IBM, and Microsoft, which are all developing quantum technologies of their own. But much of this work has been done in the U.S. so far. Changing that focus must be a priority if Europe is to garner appropriate rewards from its billion-euro investment.

Ref: arxiv.org/abs/1712.03773 : The European Quantum Technologies Roadmap