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In October 2019, Google researchers announced the arrival of “quantum supremacy” in a paper published on NASA’s website (which was later removed). Quantum supremacy is the state in which quantum computers can be shown to perform any task better than a conventional classical computer can, and it is the main area of focus for many researchers, institutions, government agencies and technology companies (like Google) today.
While the Google researchers’ rescinded announcement cannot yet be taken as the dawn of a new era in computing, it does reflect the promise of quantum computers to come. These computers – through manipulation of the peculiar mechanical features of nano-scale particles – could drive a more optimized, data-rich, connected world in the future. But what will drive them?
Energy Needed for Quantum Computing
Manipulating quantum (that is, the smallest possible interacting) particles requires extremely precise nano-engineering in controlled laboratory environments. While different methods for producing the qubits (units of information which are connected to one another through entanglement and which can be in a superposition of two states at once) needed for quantum computers do exist, all of these are currently very power-hungry.
For instance, many quantum computers can only operate in extremely low temperatures. IBM’s Q needs an environmental temperature of 10 millikelvin (around -273.14 degrees Celsius) to work. This is achieved with liquid helium, which requires vast amounts of energy to produce. Solar energy power – and indeed, electricity alone – is not enough to achieve these extremely low temperatures.
Other quantum computers, which attain qubit states with ion traps, can only work in a perfect vacuum. This is another laboratory environment that would be impossible to achieve with the limited power that comes from solar energy today.
However, if these environmental requirements can be overcome – and this is the research aim of many quantum computer scientists – then there is in principle no reason that quantum computers would require more energy than classical computers to perform the same functions (once it has been demonstrated that they can even do this). If qubit states can be created, controlled, and measured in an architecture that does not require extremely low temperatures or laboratory vacuums, then quantum computers could be powered by solar energy just as desktop computers are today.
Accessing Quantum Computers with Classical Computers
While a commercially available quantum computer that does not require laboratory conditions to work is still a distant goal for researchers in the field, using quantum computing power is already a reality for many.
One way of achieving this is through simulation. Powerful classical computers can be programmed to simulate the peculiar quantum mechanics of entanglement and superposition, and such simulation has been demonstrated to compute quantum algorithms that previously had only been put forward in theoretical papers.
IBM has offered access to its IBM Q quantum computer through its Quantum Experience program. Anybody can use the Q through either a web-based 5-qubit configuration or a 16-qubit configuration accessed with a software development kit offered by IBM.
In these ways, quantum computing can be largely powered by solar energy, as more and more of the national grids that supply classical computers with power are themselves supplied by solar energy. Many researchers in the field envisage a near future in which everybody has access to quantum computing power via their regular, classical computing devices.
If true quantum supremacy (in which a quantum computer can perform any process better than a classical computer, rather than Google’s version of supremacy in which the Sycamore chip performed one process that classical computers cannot) is achieved in the near future, it will be in a quantum computer-operated under strict laboratory conditions.
These conditions cannot be achieved with solar energy alone; however, they could take over processing tasks from any number of classical computers giving those computers even more energy-efficiency. In turn, quantum computing could drive a more solar-powered – and sustainable – connected world.
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