26 September, 2019
3 Min Read
GS-III: Quantum Supremacy.
A draft research paper claimed Google researchers have achieved a long-ought-after goal in physics called “quantum supremacy”.
What is quantum computing?
How is Quantum computer different from a traditional computer?
Source: Indian Express
10 March, 2020
9 Min Read
Part of: GS Prelims and GS-III- S&T
Recently, Google’s quantum computer, named Sycamore, claimed “quantum supremacy”, as it reportedly did the task in 200 seconds that would have apparently taken a supercomputer 10,000 years to complete.
What is “quantum supremacy”?
Quantum Computing vs Traditional Computing
What is quantum computing?
Let’s start with the basics.
An ordinary computer chip uses bits. These are like tiny switches, that can either be in the off position – represented by a zero – or in the on position – represented by a one. Every app you use, website you visit and photograph you take is ultimately made up of millions of these bits in some combination of ones and zeroes.
This works great for most things, but it doesn’t reflect the way the universe actually works. In nature, things aren’t just on or off. They’re uncertain. And even our best supercomputers aren’t very good at dealing with uncertainty. That’s a problem.
That's because, over the last century, physicists have discovered when you go down to a really small scale, weird things start to happen. They’ve developed a whole new field of science to try and explain them. It’s called quantum mechanics.
Quantum mechanics is the foundation of physics, which underlies chemistry, which is the foundation of biology. So for scientists to accurately simulate any of those things, they need a better way of making calculations that can handle uncertainty. Enter, quantum computers.
How do quantum computers work?
Instead of bits, quantum computers use qubits. Rather than just being on or off, qubits can also be in what’s called ‘superposition’ – where they’re both on and off at the same time, or somewhere on a spectrum between the two.
Take a coin. If you flip it, it can either be heads or tails. But if you spin it – it’s got a chance of landing on heads, and a chance of landing on tails. Until you measure it, by stopping the coin, it can be either. Superposition is like a spinning coin, and it’s one of the things that makes quantum computers so powerful. A qubit allows for uncertainty.
If you ask a normal computer to figure its way out of a maze, it will try every single branch in turn, ruling them all out individually until it finds the right one. A quantum computer can go down every path of the maze at once. It can hold uncertainty in its head.
It’s a bit like keeping a finger in the pages of a choose your own adventure book. If your character dies, you can immediately choose a different path, instead of having to return to the start of the book.
The other thing that qubits can do is called entanglement. Normally, if you flip two coins, the result of one coin toss has no bearing on the result of the other one. They’re independent. In entanglement, two particles are linked together, even if they’re physically separate. If one comes up heads, the other one will also be heads.
It sounds like magic, and physicists still don’t fully understand how or why it works. But in the realm of quantum computing, it means that you can move information around, even if it contains uncertainty. You can take that spinning coin and use it to perform complex calculations. And if you can string together multiple qubits, you can tackle problems that would take our best computers millions of years to solve.
What can quantum computers do?
Quantum computers aren’t just about doing things faster or more efficiently. They’ll let us do things that we couldn’t even have dreamed of without them. Things that even the best supercomputer just isn’t capable of.
They have the potential to rapidly accelerate the development of artificial intelligence. Google is already using them to improve the software of self-driving cars. They’ll also be vital for modelling chemical reactions.
Right now, supercomputers can only analyse the most basic molecules. But quantum computers operate using the same quantum properties as the molecules they’re trying to simulate. They should have no problem handling even the most complicated reactions.
That could mean more efficient products – from new materials for batteries in electric cars, through to better and cheaper drugs, or vastly improved solar panels. Scientists hope that quantum simulations could even help find a cure for Alzheimer’s.
Quantum computers will find a use anywhere where there’s a large, uncertain complicated system that needs to be simulated. That could be anything from predicting the financial markets, to improving weather forecasts, to modelling the behaviour of individual electrons: using quantum computing to understand quantum physics.
Cryptography will be another key application. Right now, a lot of encryption systems rely on the difficulty of breaking down large numbers into prime numbers. This is called factoring, and for classical computers, it’s slow, expensive and impractical. But quantum computers can do it easily. And that could put our data at risk.
There are rumours that intelligence agencies across the world are already stockpiling vast amounts of encrypted data in the hope that they’ll soon have access to a quantum computer that can crack it.
The only way to fight back is with quantum encryption. This relies on the uncertainty principle – the idea that you can’t measure something without influencing the result. Quantum encryption keys could not be copied or hacked. They would be completely unbreakable.
How will it help us?
Challenges Associated with Quantum Computing
02 December, 2020
3 Min Read
What is Quantum Supremacy?
Differences between a standard computer and a quantum computer:
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