Quantum Supremacy | 26 Oct 2019

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”?

• The phrase “quantum supremacy” was coined in 2012 by John Preskill.
• Quantum supremacy refers to a quantum computer solving a problem that cannot be expected of a classical computer in a normal lifetime.

Quantum Computing vs Traditional Computing

• Traditional computers work on the basis of the laws of classical physics, specifically by utilizing the flow of electricity. A quantum computer, on the other hand, seeks to exploit the laws that govern the behavior of atoms and subatomic particles.
• 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.
• Because of quantum superposition, a quantum computer — if it works to plan — can mimic several classical computers working in parallel.
• World's most powerful supercomputers today can juggle 148,000 trillion operations in a second and requires about 9000 IBM CPUs connected in a particular combination to achieve this feat.
• At that tiny scale, many laws of classical physics cease to apply, and the unique laws of quantum physics come into play.
• Unlike classical physics, in which an object can exist in one place at one time, quantum physics looks at the probabilities of an object being at different points. Existence in multiple states is called superposition, and the relationships among these states is called entanglement.
• The higher the number of qubits, the higher the amount of information stored in them. Compared to the information stored in the same number of bits, the information in qubits rises exponentially. That is what makes a quantum computer so powerful.
• Building reliable quantum hardware is challenging because of the difficulty of controlling quantum systems accurately.

How will it help us?

• The speed and capability of classical supercomputers are limited by energy requirements. Along with these they also need more physical space.
• It can have a major impact through quantum chemistry, which could be important in agriculture and human health.
• It could help with the development of new pharmaceuticals, new energy sources, new ways to collect solar power, and new materials.
• Looking for really useful information by processing huge amounts of data quickly is a real-world problem and one that can be tackled faster by quantum computers.
  
  • For example, if we have a database of a million social media profiles and had to look for a particular individual, a classical computer would have to scan each one of those profiles which would amount to a million steps.
• In 1996, Lov K. Grover from Bell Labs discovered that a quantum computer would be able to do the same task with one thousand steps instead of a million. That translates into reduced processors and reduced energy.
• A quantum computer 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.
• Quantum computers would also be useful for tasks which handle huge amounts of data. Data mining and artificial intelligence would be major beneficiaries, along with sciences which deal in volumes of data, from astronomy to linguistics.

Government's Initiative

• 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.

Challenges Associated with Quantum Computing

• The dark side of quantum computing is the disruptive effect that it can have on cryptographic encryption, which secures communications and computers.
• It might pose a challenge for the government also because if this technology goes into wrong hands, all the government’s official and confidential data will be at a risk of being hacked and misused.

Way Forward

• Long after the birth of social media and artificial intelligence, there are now demands to regulate them. It would be prudent to develop a regulatory framework for quantum computing before it becomes widely available.
• It will be better to regulate it or define the limits of its legitimate use, nationally and internationally before the problem gets out of hand like nuclear technology.