Quantum computers, which are based on the strange rules of quantum mechanics, will revolutionise society in a similar way to how mechanical computers have. Once built, they will help us answer many questions in science, create lifesaving medicines, provide transformative capabilities for the financial sector and in general solve certain problems that an ordinary computer would take billions of years to compute.
It is very difficult to estimate the full impact of quantum computers, as we are only starting to develop a new class of algorithms that may run on such a machine.
However, one thing is clear. Nature works according to quantum physics, so quantum computers may be the very best tool possible to understand nature and the fabric of reality itself.
So far, most of the research into quantum computing has been academic. But we have now managed to draw up an actual nuts and bolts construction plan to build a large-scale quantum computer, published in the journal Science Advances.
While small-scale quantum computers have already been built (for example, at the University of Sussex) they only demonstrate some of the physics involved and are too small to solve some of the more interesting problems.
Quantum computers work by exploiting so-called quantum effects. One of the most important ones is “superposition” – the fact that an object can be in two different places at the same time. Yes, you heard right. But what does that even mean? Does this enable me to have a holiday in sunny California and at the same time write this article in the UK?
Not quite, we mostly see quantum effects on the “microcosmos” level of atoms and molecules. For example, physicists around the world have managed to conduct studies showing an atom can be in two different places at the same time. However, such experiments are very difficult because even the slightest contact between an atom exhibiting quantum effects and anything else will make these effects disappear – immediately.
This is why it is so difficult to build an actual quantum computer and why it’s easier to build small prototypes. So far, the leading technology thought to be capable of building a quantum computer are trapped ions (atoms that have lost an electron, making them charged) that are trapped by electric fields. This is what we have used. I should mention that there is a second very successful technology, making use of “superconducting” circuitry (where there is nearly zero resistance), however, its practical implementation is quite challenging as it can only operate at extremely low temperatures.
Science news in pictures
Science news in pictures
1/20 'Tiny vampires' existed millions of years ago
Scientists have discovered that microscopic 'vampire' amoebae existed hundreds of millions of years ago, and they may have been some of the first predators on Earth. By examining ancient fossils with an electron microscope, paleobiologist Susannah Porter from UC Santa Barbara discovered tiny holes which may have been drilled by vampiric microbes. The tiny creatures are believed to be the ancestors of modern Vampyrellidae amoebae, and punctured holes in their prey before sucking out the contents of their cells
2/20 Kepler 62f
An Earth-like planet orbiting a star 1,200 light years away could have conditions suitable for life, say scientists. Kepler 62f is about 40 per cent larger than the Earth and may possess surface oceans. It is the outermost of five planets circling a star that is smaller and cooler than the sun discovered by the American space agency Nasa's Kepler space telescope in 2013
3/20 Vegetables grow well in soil from Mars
Scientists have taken a leaf out of the script of The Martian by showing how easy it would be to grow your own veg on the Red Planet. In the hit Ridley Scott film, a stranded astronaut played by Matt Damon uses his botanical skills to cultivate potatoes. Now his success has been emulated by researchers in the Netherlands who harvested tomatoes, peas, rye, rocket, radish and cress raised on simulated Martian soil supplied by Nasa
4/20 Ancient Roman 'leisure complex' unearthed in Jerusalem
An ancient Roman estate complete with its own wine press and bathhouse has been unearthed in Jerusalem. A series of buildings dating back at least 1,600 years were discovered underneath the city's famous Schneller Orphanage which operated on the site from 1860 until the end of the Second World War, when it was turned into an army base. The ruins were discovered by archaeologists from the Israel Antiquities Authority who were excavating the site ahead of building new flats for the city's Orthodox Jewish community
5/20 Scientists discover possible new species of deep-sea octopus nicknamed 'Casper'
Scientists believe they may have found a new species of octopus likened in appearance to Casper, the friendly cartoon ghost. Researchers with the US National Oceanic and Atmospheric Administration made the discovery by chance as they searched the seabed on an unrelated mission collecting geological samples. Teams were operating an unmanned submarine on the Pacific Ocean floor at depths of more than four kilometres (two-and-a-half miles) in the Hawaiian Islands when they spotted the unusual creature
6/20 Black hole captured eating a star then vomiting it back out
Astronomers have captured a black hole eating a star and then sicking a bit of it back up for the first time ever. The scientists tracked a star about as big as our sun as it was pulled from its normal path and into that of a supermassive black hole before being eaten up. They then saw a high-speed flare get thrust out, escaping from the rim of the black hole. Scientists have seen black holes killing and swallowing stars. And the jets have been seen before.But a new study shows the first time that they have captured the hot flare that comes out just afterwards. And the flare and then swallowed star have not been linked together before
7/20 'Male and female brains' aren't real
Brains cannot be categorised into female and male, according to the first study to look at sex differences in the whole brain. Specific parts of the brain do show sex differences, but individual brains rarely have all “male” traits or all “female” traits. Some characteristics are more common in women, while some are more common in men, and some are common in both men and women, according to the study
8/20 Dog-sized horned dinosaur fossil found shows east-west evolutionary divide in North America
A British scientist has uncovered the fossil of a dog-sized horned dinosaur that roamed eastern North America up to 100 million years ago. The fragment of jaw bone provides evidence of an east-west divide in the evolution of dinosaurs on the North American continent. During the Late Cretaceous period, 66 to 100 million years ago, the land mass was split into two continents by a shallow sea. This sea, the Western Interior Seaway, ran from the Gulf of Mexico to the Arctic Ocean. Dinosaurs living in the western continent, called Laramidia, were similar to those found in Asia
9/20 Asteroid to skim past Earth on Halloween 2015
A huge asteroid is set to skim by Earth on Halloween, just three weeks after it was first spotted. The rock is travelling through space at 78,000 miles per hour, and will fly past the Earth at a distance of only 300,000 miles – only slightly further away than our moon, and easily close enough for Nasa to class it a potentially hazardous object. The asteroid is bigger than a skyscraper
10/20 Life on Earth appeared hundreds of millions of years earlier than previously thought
Life may have come to earth 4.1 billion years ago, hundreds of millions of years earlier than we knew. The discovery, made using graphite that was trapped in ancient crystals, could mean that life began "almost instantaneously" after the Earth was formed. The researchers behind it have described the discovery as “a potentially transformational scientific advance”. Previously, life on Earth was understood to have begun when the inner solar system was hit by a massive bombardment from space, which also formed the moon's craters
11/20 Earth could be at risk of meteor impacts
Earth could be in danger as our galaxy throws out comets that could hurtle towards us and wipe us out, scientists have warned. Scientists have previously presumed that we are in a relatively safe period for meteor impacts, which are linked with the journey of our sun and its planets, including Earth, through the Milky Way. But some orbits might be more upset than we know, and there is evidence of recent activity, which could mean that we are passing through another meteor shower. Showers of meteors periodically pass through the area where the Earth is, as gravitational disturbances upset the Oort Cloud, which is a shell of icy objects on the edge of the solar system. They happen on a 26-million year cycle, scientists have said, which coincide with mass extinctions over the last 260-million years
12/20 Genetically-engineered, extra-muscular dogs
Chinese scientists have created genetically-engineered, extra-muscular dogs, after editing the genes of the animals for the first time. The scientists create beagles that have double the amount of muscle mass by deleting a certain gene, reports the MIT Technology Review. The mutant dogs have “more muscles and are expected to have stronger running ability, which is good for hunting, police (military) applications”, Liangxue Lai, one of the researchers on the project. Now the team hope to go on to create other modified dogs, including those that are engineered to have human diseases like muscular dystrophy or Parkinson’s. Since dogs’ anatomy is similar to those of humans’, intentionally creating dogs with certain human genetic traits could allow scientists to further understand how they occur
13/20 Nasa confirms Mars water discovery
Nasa has announced that it has found evidence of flowing water on Mars. Scientists have long speculated that Recurring Slope Lineae — or dark patches — on Mars were made up of briny water but the new findings prove that those patches are caused by liquid water, which it has established by finding hydrated salts.
14/20 Bees in the Rocky Mountains are evolving shorter tongues
With warmer summers, flowers in the Rockies have become shallower and more suited to shorter-tongued bees
15/20 The majority of the UK public believe in aliens
The titular alien character from 2011's 'Paul' - a poll has found the majority of the public in Britain, Germany and the US believe that intelligent life is out there in the universe
16/20 Researchers discover 'lost world' of arctic dinosaurs
Scientists say that the new dinosaur, known as Ugrunaaluk kuukpikensis, “challenges everything we thought about a dinosaur’s physiology”. Florida State University professor of biological science Greg Erickson said: “It creates this natural question. How did they survive up here?”
17/20 Scientists find exactly what human corpses smell like
New research has become the first to isolate the particular scent of human death, describing the various chemicals that are emitted by corpses in an attempt to help find them in the future. The researchers hope that the findings are the first step towards working on a synthetic smell that could train cadaver dogs to be able to more accurately find human bodies, or to eventually developing electronic devices that can look for the scent themselves.
18/20 The Syrian civil war has caused the first ever withdrawal from the 'doomsday bank'
Researchers in the Middle East have asked for seeds including those of wheat, barley and grasses, all of which are chosen because especially resistant to dry conditions. It is the first withdrawal from the bank, which was built in 2008. Those researchers would normally request the seeds from a bank in Aleppo. But that centre has been damaged by the war — while some of its functions continue, and its cold storage still works, it has been unable to provide the seeds that are needed by the rest of the Middle East, as it once did.
19/20 A team of filmmakers in the US have made the first ever scale model of the Solar System in a Nevada desert
Illustrations of the Earth and moon show the two to be quite close together, Mr Overstreet said. This is inaccurate, the reason being that these images are not to scale.
20/20 Academics claim a full bladder makes for a better liar
People lie more convincingly if they have a full bladder, according to research by academics at California State University. Iris Blandón-Gitlin's team asked 22 students to lie to a panel of interviewers. Half were given 700ml to drink before the interview and the other half, just 50ml. The students with the full bladders showed fewer signs that they were lying and their untrue answers were longer and more detailed, meaning interviewers were less able to detect that they were telling porkies. PM David Cameron has previously attested to giving speeches on a full bladder.
In the same way as a conventional computer encodes information as a series of 0’s and 1’s, also referred to as bits, a quantum computer makes use of quantum bits, which can be zero and one at the same time – giving enormous processing power! Within a trapped ion quantum computer, each ion corresponds to one quantum bit.
Animation illustrating the system design and operation of a large scale quantum computer.
So a quantum computer with a billion quantum bits requires a billion trapped ions. These ions are held levitating above a quantum microchip using electric fields. To operate a quantum computer is just like playing a game of Pacman. The quantum microchip acts like a computer mother board with the ions being transported using electric fields from memory regions to processing regions and beyond.
For many years, I have seen looks of disbelief on the faces of some of my colleagues when I told them about our intention to build a large-scale quantum computer. But with with tremendous progress in the field in the last few years, (here is an example from my group at Sussex), more people are starting to believe it may actually be achievable.
Our mission was to come up with the simplest technology solution possible and to make use of proven technology wherever possible. We wanted to identify the most important engineering challenges and deliver credible solutions. In order to make this happen, I enlisted some extremely talented scientists from around the world to help us to draw up a blueprint.
We did not just want to write another academic study. So we tried to focus on the actual engineering. How big will it be? What about the power consumption? What parts does it require? What kind of cooling does it need? Providing all these details was a very tedious process, but it provides the answer to the most important question: can such a device actually be built? And while we still believe it will be quite an engineering feat, tremendously expensive and requiring a lot of people, I think it is fair to say that the answer is yes.
We kept the paper on an archive server accessible to other scientists for several years. This allowed us to gather critical feedback and by addressing this feedback further refine the plan. Have we really addressed all possible problems? We cannot know for sure, but so far I have not heard any substantial criticism that we believe cannot be addressed.
Explaining the concept.
So let’s talk about the actual blueprint. A quantum computer needs to be constructed from many individual modules. Why? Because if you just use one module, the ultimate processing power will always be limited by the largest module size that could be constructed with current technology. What we developed is a concept where the quantum computer consists of many modules and ions can be transported from one module to another using electric fields in order to connect the modules to perform difficult calculations. Using this approach is a lot simpler than previously proposed ideas to connect modules.
One of these ideas had been to connect individual quantum computer modules using optical fibres. In order for that to work, quantum bits need to be exchanged making use of individual particles of light, so called photons. This is still quite a slow process, although I’m confident it will be improved with some time and effort. But for now, we instead made use of a new invention transporting actual ions from one module to another using electric fields.
We aim to construct really powerful quantum computers that will fill a building or maybe even a football pitch and use a lot of power. The development cost is hard to estimate but might be in the range of £100m.
But, at least with this technical plan, we believe a large-scale quantum computer is not the stuff of science fiction movies anymore. Even though I should stress that it still is very hard.
Winfried Hensinger, professor of quantum technologies (physics and astronomy), University of Sussex. This article first appeared on The Conversation (theconversation.com)