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The challenges of quantum computing

GS Paper 3

Syllabus: Science and Technology- Developments and their Applications and Effects in Everyday Life


Source: TH

 Direction: The article tries to explain quantum technology, its working, application, challenges and way ahead to make it more practical.

 Context: Several institutes and companies worldwide have invested in developing quantum computer (QC) systems.


  • The QC use quantum physics to tackle problems that traditional computers cannot and given its wide-ranging applications and the scale of investments, understanding QCs are crucial.
  • In 2021, the Indian government launched a National Mission on Quantum Technology to study quantum technologies with an allocation of ₹8,000 crores.
  • The Indian army opened a quantum research facility in Madhya Pradesh and the Department of Science and Technology co-launched another facility in Pune.


Quantum technology: 


  • Until the early 20th century, it was thought that classical physics – two objects cannot occupy the same space at the same moment.
  • Upon scientific investigation, microscopic/sub-atomic particles such as atoms, electrons, and photons, the subject of quantum mechanics (physics of subatomic particles) were founded. 

About: Quantum technology works by using the principles of quantum mechanics and is based on the phenomena exhibited by microscopic particles (photons, electrons, atoms, etc) which are quite distinct from the way normal macroscopic objects behave. 

The principles behind quantum technology:



  • A bit is the fundamental computational unit of a conventional computer, whose value is 1 if a corresponding transistor is on and 0 if the transistor is off. This means a bit can have one of two values at a time, either 0 or 1.
  • The qubit is the fundamental unit of a QC and instead of being either 1 or 0, the information is encoded in the third kind of state (superimposition of 0 & 1).
  • Thus, a qubit-based computer can access more computational pathways and offer solutions to more complex problems.



  • Quantum supremacy: a situation where quantum computers can do things that classical computers cannot.
  • Quantum computers, which provide more powerful computing, help in a wide range of applications like –
    • More reliable navigation, timing systems and secure communications.
    • Quantum sensing (using quantum phenomenon to perform a measurement of a physical quantity).
    • Disaster management through better prediction, etc.
    • To understand biological phenomena such as the spread of pandemics like Covid-19, etc.



  • A practical QC needs at least 1,000 qubits and the current biggest quantum processor has 433 qubits.
  • Qubits exist in superposition in specific conditions, including very low temperatures (~0.01 K), with radiation ­shielding and protection against physical shock.
  • Material or electromagnetic defects in the circuitry between qubits could also ‘corrupt’ their states.
  • Researchers are yet to build QCs that completely eliminate these disturbances in systems.


Way ahead: To entangle each qubit with a group of physical qubits (a system that mimics a qubit) that correct errors.


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Q. What is quantum computing? Explain its applications and steps taken by India to promote quantum technologies in the country. (250 words)