Tech websites and theoretical computer-science outlets were aflame earlier this week after a story said that Google had claimed to have achieved ‘quantum supremacy’. In a line, it means that researchers at Google had solved a really difficult problem in seconds with the help of quantum computers which a supercomputer could not. The ideas governing quantum computers have been around since the 1990s but actual machines have been around since 2011, most notably built by Canadian company D-Wave Systems
What has Google achieved?
Quantum supremacy refers to quantum computers being able to solve a problem that a classical computer cannot. In the research paper, Google used a 53-qubit processor to generate a sequence of millions of numbers. Though these numbers appeared randomly generated, they conform to an algorithm generated by Google. A classical supercomputer checked some of these values and they were correct. Google’s quantum computer, named Sycamore, claimed ‘supremacy’ because it reportedly did the task in 200 seconds that would have apparently taken a supercomputer 10,000 years to complete.
What are quantum computers?
Quantum computers work differently from the classical computers we work on today.
Exploiting the principles of quantum mechanics, they can easily tackle computational problems that may be tough for the classical computer as the size of the numbers and number of inputs involved grows bigger.
Conventional computers process information in ‘bits’ or 1s and 0s, following classical physics under which our computers can process a ‘1’ or a ‘0’ at a time. Quantum computers compute in ‘qubits’ (or quantum bits). They exploit the properties of quantum mechanics, the science that governs how matter behaves on the atomic scale. In this scheme of things, processors can be a 1 and a 0 simultaneously, a state called quantum superposition.
While this accelerates the speed of computation, a machine with less than a 100 qubits can solve problems with a lot of data that are even theoretically beyond the capabilities of the most powerful supercomputers. Because of quantum superposition, a quantum computer — if it works to plan — can mimic several classical computers working in parallel.
In theory, a quantum computer can solve complex problems rapidly because it can attack complex problems that are beyond the scope of a classical computer. The basic advantage is speed as it is able to simulate several classical computers working in parallel
What will it mean for online banking?
Breaking banking grade encryption is far away. Scott Aaronson, a theoretical computer scientist who has written on Google’s feat, opines that current encryption standards would require a quantum computer to have “several thousand logical qubits” working in tandem perfectly.
Is India working on quantum computing?
There are no quantum computers in India yet. In 2018, the Department of Science & Technology unveiled a programme called Quantum-Enabled Science & Technology (QuEST) and committed to investing ₹80 crore over the next three years to accelerate research. The ostensible plan is to have a quantum computer built in India within the next decade. Phase-1 of the problem involves hiring research experts and establishing teams with the know-how to physically build such systems.