27082024
07:30 AM
Prelims: General Science
Mains: Science and TechnologyDevelopments in Science and Technology
Quantum computing is an area of computer science that uses the principles of quantum theory at the atomic and subatomic levels. It uses subatomic particles, such as electrons or photons. Classical computers, which include smartphones and laptops, encode information in binary “bits” that can either be 0s or 1s. In a quantum computer, the basic unit of memory is a quantum bit or qubit. Quantum bits, or qubits, allow the subatomic particles to exist in more than one state at the same time.
Theoretically, linked qubits can exploit the superposition, entanglement and interference between their wavelike quantum states to perform calculations that might otherwise take millions of years.
Quantum computers are based on these key principles of quantum physics that enable new approaches to information processing:
Key principle  Description 
Superposition   The fundamental principle that enables the power of quantum computing is 'quantum superposition'.  Unlike traditional bits used in classical computers that can exist in only one state (either 0 or 1), quantum bits or 'qubits' can exist in a superposition of 0 and 1 simultaneously. 
Quantum Entanglement
  Quantum Entanglement is where quantum particles interact physically in ways such that the quantum state of each cannot be described independently.  Measuring one particle instantaneously affects the others even over long distances.  This enables quantum systems to exhibit correlations stronger than any possible classical behaviour. 
Quantum Interference   The wavelike characteristics of quantum particles cause interference effects between different probability states that can result in constructive or destructive interference analogous to the interference effects seen in waves.

Quantum Tunneling   Quantum tunnelling refers to the ability of particles to tunnel through barriers when according to classical physics they do not have enough energy to do so.

The hardware components underlying current quantum computers include:
While both quantum and classical systems encode and process data, they have fundamental differences:
Parameter  Classical Computing  Quantum Computing 
Basic Unit  Binary Bit (0 or 1)  Qubit (0, 1 or Superposed) 
Parallelism  Sequential Processing  Massive Parallelism through Superposition 
Hardware  Silicon Chips at Room Temperature  Cryogenic Quantum Processors 
Programming  Deterministic StepbyStep Instructions  Setting up Interference for High Probability Solutions 
Speed  Fixed Rate based on Transistor Density  Potential for Exponential Increase for Specific Applications 
Accuracy  Precise Digital Output  Analog Behaviour Requiring Quantum Error Correction 
Quantum supremacy is the experimental demonstration of a quantum computer's dominance and advantage over classical computers by performing welldefined calculations previously impossible at unmatched speeds.
Quantum computing has significant applications that offer prospects of scalability. It can accelerate various fields such as:
Quantum computing emerged as one of the most promising technologies, however, there are the following limitations:
Quantum Computing has a myriad of applications in various walks of life such as secure communication, optimising industrial processes, complex chemical simulation etc.
India is gearing up to accelerate indigenous efforts around the development of quantum computing:
Question 1.Which one of the following is the context in which the term "qubit" is mentioned? (UPSC2022)
(a) Cloud Services
(b) Quantum Computing
(c) Visible Light Communication Technologies
(d) Wireless Communication Technologies
Answer: (b)
Q1. What is Quantum Computing?
Ans. Quantum computing uses principles of quantum physics such as superposition and entanglement to perform computations. It encodes information in quantum bits or qubits. This allows exponentially large information processing capacity compared to classical bits in regular computers.
Q2. How is it different from normal computers?
Ans. Instead of encoding information as 0 or 1 as in regular bits of classical computers, qubits exploit superpositions to encode information as 0 and 1 simultaneously. Operations on qubits are done using principles like interference and entanglement. This massively parallel information processing promises capabilities unattainable using regular computers.
Q3. What are the key benefits of Quantum Computing?
Ans. Some of the key advantages quantum computing promises include incredibly fast searching of unsorted databases, breaking current encryption protocols, simulating chemical & subatomic reactions, optimizing systems involving too many parameters for classical techniques and advancing machine learning.
Q4. What is Quantum Supremacy?
Ans. Quantum supremacy is a milestone that is expressed in the exceptional computing ability of quantum computers to perform some exceptional computational tasks which is presently not possible with the conventional computing system.
Q5. What are the major challenges to Quantum Computing?
Ans. Major challenges of quantum computing include the fragility of quantum particles, decoherence, and loss of superposition property while taking observance.
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