{"id":6150,"date":"2026-01-04T12:41:51","date_gmt":"2026-01-04T07:11:51","guid":{"rendered":"https:\/\/vajiramandravi.com\/upsc-exam\/?p=6150"},"modified":"2026-01-05T11:35:25","modified_gmt":"2026-01-05T06:05:25","slug":"quantum-computing","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/upsc-exam\/quantum-computing\/","title":{"rendered":"Quantum Computing, Meaning, Applications, Advantages, UPSC Notes"},"content":{"rendered":"<p>Quantum computing is an area of computer science that uses the\u00a0<strong>principles of quantum theory\u00a0<\/strong>at the\u00a0<strong>atomic and subatomic levels.\u00a0<\/strong>It uses subatomic particles, such as\u00a0<strong>electrons\u00a0<\/strong>or\u00a0<strong>photons<\/strong>. Classical computers, which include smartphones and laptops, encode information in binary\u00a0<strong>\u201cbits\u201d<\/strong>\u00a0that can either be\u00a0<strong>0s or 1s.<\/strong>\u00a0In a quantum computer, the basic unit of memory is a quantum bit or qubit.\u00a0<strong>Quantum bits, or qubits<\/strong>, allow the subatomic particles to exist in more than one state at the same time.<\/p>\r\n<p>Theoretically, linked qubits can exploit the superposition, entanglement and interference between their wave-like quantum states to perform calculations that might otherwise take millions of years.<\/p>\r\n<h2>Key Principles of Quantum Computing<\/h2>\r\n<p>Quantum computers are based on these key principles of quantum physics that enable new approaches to information processing:<\/p>\r\n<figure>\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td class=\"tb-color\"><strong>Key principle<\/strong><\/td>\r\n<td class=\"tb-color\"><strong>Description<\/strong><\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Superposition<\/strong><br \/>\r\n<img decoding=\"async\" src=\"https:\/\/vajiram-prod.s3.ap-south-1.amazonaws.com\/superposition_16e6bab3e9.webp\" alt=\"Superposition\" \/><\/td>\r\n<td>\r\n<p>- The fundamental principle that enables the power of quantum computing is\u00a0<strong>'quantum superposition'.\u00a0<\/strong><\/p>\r\n<p>- Unlike traditional bits used in classical computers that can exist in only one state\u00a0<strong>(either 0 or 1),<\/strong>\u00a0quantum bits or\u00a0<strong>'qubits'\u00a0<\/strong>can exist in a superposition of 0 and 1 simultaneously.<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>\r\n<p><a href=\"https:\/\/vajiramandravi.com\/upsc-exam\/quantum-entanglement\/\" target=\"_blank\"><strong>Quantum Entanglement<\/strong><\/a><\/p>\r\n<p><img decoding=\"async\" src=\"https:\/\/vajiram-prod.s3.ap-south-1.amazonaws.com\/entanglement_2c1768a0ff.webp\" alt=\"Entanglement\" \/><\/p>\r\n<\/td>\r\n<td>\r\n<p>- Quantum Entanglement is where\u00a0<strong>quantum particles interact physically<\/strong>\u00a0in ways such that the quantum state of each cannot be described independently.<\/p>\r\n<p>- Measuring one particle instantaneously affects the others even over long distances.<\/p>\r\n<p>- This enables quantum systems to\u00a0<strong>exhibit correlations<\/strong>\u00a0stronger than any possible classical behaviour.<\/p>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Quantum Interference<\/strong><br \/>\r\n<img decoding=\"async\" src=\"https:\/\/vajiram-prod.s3.ap-south-1.amazonaws.com\/constructive_destructive_interference_b8283395d5.webp\" alt=\"Constructive Destructive Interference\" \/><\/td>\r\n<td>\r\n<p>- The\u00a0<strong>wave-like\u00a0<\/strong>characteristics of quantum particles cause interference effects between different probability states that can result in\u00a0<strong>constructive or destructive interference<\/strong>\u00a0analogous to the interference effects seen in waves.<\/p>\r\n<ul>\r\n\t<li>This effect is harnessed in\u00a0<strong>quantum algorithms.<\/strong><\/li>\r\n<\/ul>\r\n<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Quantum Tunneling<\/strong><br \/>\r\n<img decoding=\"async\" src=\"https:\/\/vajiram-prod.s3.ap-south-1.amazonaws.com\/tunneling_e313678c72.webp\" alt=\"Tunneling\" \/><\/td>\r\n<td>\r\n<p>- Quantum tunnelling refers to the\u00a0<strong>ability of particles to tunnel through barriers<\/strong>\u00a0when according to classical physics they do not have enough energy to do so.<\/p>\r\n<ul>\r\n\t<li>This principle is critical for the functioning of quantum computer hardware like\u00a0<strong>quantum dots<\/strong>.<\/li>\r\n<\/ul>\r\n<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>\r\n<h3>Quantum Computer Hardware<\/h3>\r\n<p>The hardware components underlying current quantum computers include:<\/p>\r\n<figure><img decoding=\"async\" src=\"https:\/\/vajiram-prod.s3.ap-south-1.amazonaws.com\/quantum_ed6837d966.webp\" alt=\"Quantum\" \/><\/figure>\r\n<ul>\r\n\t<li><strong>Qubits:<\/strong>\u00a0As the basic units for information representation and processing, different physical systems are engineered to serve as qubits. The most common in use today are:\r\n\r\n<ul>\r\n\t<li><strong><a href=\"https:\/\/vajiramandravi.com\/upsc-exam\/superconductors\/\" target=\"_blank\">Superconducting<\/a> circuits<\/strong>\u00a0are maintained at very low temperatures.<\/li>\r\n\t<li><strong>Trapped ions<\/strong>\u00a0are manipulated using lasers and kept at an ultrahigh vacuum.<\/li>\r\n\t<li><strong>Defects in diamond crystals<\/strong>\u00a0provide stability at room temperature.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Quantum Logic Gates<\/strong>: As the counterparts of logic gates used in classical computing, quantum logic gates manipulate qubits to perform computational operations.\r\n\r\n<ul>\r\n\t<li><strong>Common single and multi-qubit gates<\/strong>\u00a0include the<strong>\u00a0Hadamard, CNOT, and SWAP gates.<\/strong><\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li>Qubits need to be maintained in a delicate state through isolation, extremely low temperatures and manipulation using precision lasers or microwave pulses applied for extremely short durations.<\/li>\r\n\t<li>The fragility severely limits the number of sequential operations that can be performed reliably.<\/li>\r\n<\/ul>\r\n<h2>Difference between Classical and Quantum Computing<\/h2>\r\n<p>While both quantum and classical systems encode and process data, they have fundamental differences:<\/p>\r\n<figure><img decoding=\"async\" src=\"https:\/\/vajiram-prod.s3.ap-south-1.amazonaws.com\/components_of_quantum_computing_systems_fff3b52c24.webp\" alt=\"Components of Quantum Computing Systems\" \/><\/figure>\r\n<figure>\r\n<table>\r\n<tbody>\r\n<tr>\r\n<td class=\"tb-color\"><strong>Parameter<\/strong><\/td>\r\n<td class=\"tb-color\"><strong>Classical Computing<\/strong><\/td>\r\n<td class=\"tb-color\"><strong>Quantum Computing<\/strong><\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Basic Unit<\/strong><\/td>\r\n<td>Binary Bit (0 or 1)<\/td>\r\n<td>Qubit (0, 1 or Superposed)<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Parallelism<\/strong><\/td>\r\n<td>Sequential Processing<\/td>\r\n<td>Massive Parallelism through Superposition<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Hardware<\/strong><\/td>\r\n<td>Silicon Chips at Room Temperature<\/td>\r\n<td>Cryogenic Quantum Processors<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Programming<\/strong><\/td>\r\n<td>Deterministic Step-by-Step Instructions<\/td>\r\n<td>Setting up Interference for High Probability Solutions<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Speed<\/strong><\/td>\r\n<td>Fixed Rate based on Transistor Density<\/td>\r\n<td>Potential for Exponential Increase for Specific Applications<\/td>\r\n<\/tr>\r\n<tr>\r\n<td><strong>Accuracy<\/strong><\/td>\r\n<td>Precise Digital Output<\/td>\r\n<td>Analog Behaviour Requiring Quantum Error Correction<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/figure>\r\n<ul>\r\n\t<li>These contrasts between classical binary and quantum paradigms give quantum computers potential advantages in solving specific problems intractable via conventional means.<\/li>\r\n<\/ul>\r\n<h3><strong>Quantum Supremacy<\/strong><\/h3>\r\n<p>Quantum supremacy is the experimental demonstration of a\u00a0<strong>quantum computer's dominance\u00a0<\/strong>and advantage over classical computers by performing well-defined calculations previously impossible at unmatched speeds.<\/p>\r\n<ul>\r\n\t<li>The term\u00a0<strong>\u201cQuantum Supremacy<\/strong>\u201d was coined by\u00a0<strong>John Preskill<\/strong>\u00a0in 2011.<\/li>\r\n\t<li>It is a\u00a0<strong>milestone of the exceptional computing capability\u00a0<\/strong>of quantum computers to perform some\u00a0<strong>exceptional computational\u00a0<\/strong>tasks.\r\n\r\n<ul>\r\n\t<li>In 2019, Google officially announced the achievement of quantum supremacy using its<strong>\u00a053-qubit quantum processor\u00a0<\/strong>named\u00a0<strong>Sycamore.<\/strong><\/li>\r\n\t<li>The computer solved a sampling problem considered practically impossible for classical systems in about 200 seconds which even the fastest supercomputers would take 10,000 years to execute.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h2>Quantum Computing Advantages<\/h2>\r\n<p>Quantum computing has significant applications that offer prospects of scalability. It can accelerate various fields such as:<\/p>\r\n<ul>\r\n\t<li><strong>Search and optimisation<\/strong>:\u00a0<strong>Grover's algorithm\u00a0<\/strong>for database search offers\u00a0<strong>quadratic speedup<\/strong>\u00a0- a database of 4 entries takes 1 lookup on a quantum computer versus 4 lookups classically.\r\n\r\n<ul>\r\n\t<li>This could enable ultra-fast search of large real-time financial, healthcare or classified datasets.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Chemical simulation:<\/strong>\u00a0Quantum computers with\u00a0<strong>50-100 qubits\u00a0<\/strong>could precisely simulate\u00a0<strong>complex enzyme mechanisms\u00a0<\/strong>and\u00a0<strong>chemical processes<\/strong>\u00a0for the industrial production of fertilizers, polymers and biomass.\r\n\r\n<ul>\r\n\t<li>This may enable the designing of better catalysts and materials.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong><a href=\"https:\/\/vajiramandravi.com\/upsc-exam\/artificial-intelligence\/\" target=\"_blank\">Artificial intelligence<\/a>:<\/strong>\u00a0Japanese researchers designed a quantum neural network that detects<strong>\u00a0credit card fraud with 63% accuracy versus 50%<\/strong>\u00a0for classical networks.\r\n\r\n<ul>\r\n\t<li>This demonstrates the potential for quantum machine learning.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Financial analysis:<\/strong>\u00a0Massively enhanced portfolio optimization, price modelling, risk analysis and economic forecasting can be achieved to alter financial services, investment strategies and economic policy.<\/li>\r\n\t<li><strong>Secure communication:<\/strong>\u00a0All widespread public-key\u00a0<strong>cryptography<\/strong>\u00a0is vulnerable to attacks using quantum algorithms negating the security of communication channels and protocols like online banking, messaging and sensitive database access.\r\n\r\n<ul>\r\n\t<li><strong>China<\/strong>\u00a0recently demonstrated\u00a0<strong>(QUESS)<\/strong>\u00a0satellite-based quantum key distribution for\u00a0<strong>hack-proof military communications.<\/strong><\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Healthcare advancement:<\/strong>\u00a0Precision modelling of protein folding mechanisms, gene sequencing, disease pathology simulations, personalised medicine and drug discovery can transform healthcare and life sciences through quantum computing.<\/li>\r\n\t<li><strong>Climate change science:<\/strong>\u00a0NASA plans to use quantum computing for very high-resolution regional and global scale climate modelling by assimilating large datasets using quantum neural networks.<\/li>\r\n<\/ul>\r\n<h2>Quantum Computing Limitations<\/h2>\r\n<p>Quantum computing emerged as one of the most promising technologies, however, there are the following limitations:<\/p>\r\n<ul>\r\n\t<li><strong>Hardware fragility:<\/strong>\u00a0Google's 72-qubit quantum computer requires temperatures near absolute zero inside vacuum chambers, with vibration dampening and magnetic shielding increasing complexity.<\/li>\r\n\t<li><strong>Decoherence:<\/strong>\u00a0IBM researchers reported the coherence time for a 27-qubit system was 47 microseconds - too short for practical error correction schemes.<\/li>\r\n\t<li><strong>Lack of standards:\u00a0<\/strong>Currently no standards exist for quantum programming languages and software tools.\r\n\r\n<ul>\r\n\t<li>\u00a0Recently IBM and Microsoft clashed over how fidelity benchmarks are defined across superconducting, ion trap and photonics hardware.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Qubit scalability:<\/strong>\u00a0Intel's 49-qubit superconducting quantum chip Pushan is a high watermark.\r\n\r\n<ul>\r\n\t<li>However, the company hasn't elaborated a roadmap for the millions of qubits likely needed for quantum advantage in domains like machine learning or chemical simulation.<\/li>\r\n<\/ul>\r\n<\/li>\r\n<\/ul>\r\n<h2>Quantum Computing Applications<\/h2>\r\n<p>Quantum Computing has a myriad of applications in various walks of life such as secure communication, optimising industrial processes, complex chemical simulation etc.<\/p>\r\n<ul>\r\n\t<li><strong>Drug Designing:\u00a0<\/strong>QCs overcome the limitations of existing computational methods to know the\u00a0<strong>behaviour of particles.\u00a0<\/strong>It could employ entanglement and superposition to leverage and handle all the\u00a0<strong>possible permutations of molecular behaviour of drugs\u00a0<\/strong>efficiently.\r\n\r\n<ul>\r\n\t<li><strong>For example:<\/strong>\u00a0Pharma research outfits such as SRI International, and AstraZeneca explore QC\u2019s<strong>\u00a0potential in modeling protein.<\/strong><\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Artificial Intelligence and Machine Learning:\u00a0<\/strong>Quantum computers have the potential to accelerate or improve machine learning relative to classical performance. It harnesses\u00a0<strong>statistical distribution to<\/strong>\u00a0tackle machine-learning problems efficiently.\r\n\r\n<ul>\r\n\t<li><strong>For example:<\/strong>\u00a0IBM came up with a promising machine-learning classification algorithm- a\u00a0<strong>quantum-classical hybrid.<\/strong><\/li>\r\n\t<li data-start=\"566\" data-end=\"621\">\r\n<p data-start=\"568\" data-end=\"621\"><strong data-start=\"572\" data-end=\"591\">Majorana 1 chip<\/strong> has been introduced by\u00a0<strong data-start=\"646\" data-end=\"659\">Microsoft<\/strong> and collaborators like <strong data-start=\"683\" data-end=\"697\">Quantinuum<\/strong> and <strong data-start=\"702\" data-end=\"715\">Station Q<\/strong> in their <strong data-start=\"725\" data-end=\"767\">topological quantum computing research<\/strong>. It is <span style=\"font-weight: 400\">expected that <\/span><b>Majorana 1<\/b><span style=\"font-weight: 400\"> chip will enable quantum computing.<\/span><\/p>\r\n<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Optimisation:\u00a0<\/strong>Quantum computing can improve research and development, production processes, and supply-chain optimization.\r\n\r\n<ul>\r\n\t<li><strong>For example-<\/strong>\u00a0quantum computing decreases manufacturing process\u2013related costs and also reduces cycle times by optimizing elements such as path planning in complex processes.<\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Financial sector:<\/strong>\u00a0quantum optimization of loan portfolios so that lenders can make better decisions, free up capital, lower interest rates, and improve their offerings.<\/li>\r\n\t<li><strong>Auto-industry:\u00a0<\/strong>QCs\u2019 potential to simulate quantum mechanics could be equally transformative in other\u00a0<strong>chemistry-related realms.<\/strong>\r\n<ul>\r\n\t<li>Eg: The auto industry wants to harness the technology to<strong>\u00a0build better car batteries.<\/strong><\/li>\r\n<\/ul>\r\n<\/li>\r\n\t<li><strong>Cryptography:\u00a0<\/strong>QCs\u2019 enabled encryption ensures hack-free data transmission by using\u00a0<strong>superdense coding<\/strong>\u00a0-secure quantum communication protocol.<\/li>\r\n\t<li><strong>Astronomy:\u00a0<\/strong>Quantum computing could reveal the mystery of unique processes of the universe such as the\u00a0<strong><a href=\"https:\/\/vajiramandravi.com\/upsc-exam\/big-bang-theory\/\" target=\"_blank\">Big Bang<\/a> and <a href=\"https:\/\/vajiramandravi.com\/upsc-exam\/black-hole\/\" target=\"_blank\">black holes<\/a><\/strong>, due to its ability to simulate molecules, and molecular processes of the universe.<\/li>\r\n<\/ul>\r\n<h2>Quantum Computing in India<\/h2>\r\n<p>India is gearing up to accelerate indigenous efforts around the development of quantum computing:<\/p>\r\n<ul>\r\n\t<li><strong>Budget 2023:<\/strong>\u00a0Rs 6000 crore (USD 800 million) allocated towards a National Mission on Quantum Computing and Technology spanning 5 years.<\/li>\r\n\t<li><strong>TCS National Qualifier Test 2023<\/strong>: Conducted a first-of-its-kind online test to identify talent for building quantum computing skills and knowledge across India\u2019s universities.<\/li>\r\n\t<li><strong>MeitY Initiatives:<\/strong>\u00a0Launched\u00a0<strong>Quantum Computing Applications Lab<\/strong>\u00a0on\u00a0<strong>AWS Cloud<\/strong>\u00a0focused on developing tools and methods to leverage quantum for critical national applications.<\/li>\r\n\t<li><strong>Indian Institute of Science:<\/strong>\u00a0Establishing a dedicated <a href=\"https:\/\/vajiramandravi.com\/upsc-exam\/quantum-technology\/\" target=\"_blank\">Quantum Technologies<\/a> and Application Centre to conduct research around\u00a0<strong>NISQ computing software<\/strong>\u00a0and\u00a0<strong>hybrid quantum-classical algorithms.<\/strong><\/li>\r\n\t<li><strong>Indian Institute of Technology Madras:<\/strong>\u00a0Undertaking fundamental R&amp;D across\u00a0<strong>quantum cryptography, communication, sensing,\u00a0<\/strong>and\u00a0<strong>network<\/strong>s while also establishing the Centre for Quantum Information, Communication and Computing.<\/li>\r\n<\/ul>\r\n<h2>Quantum Computing UPSC PYQ<\/h2>\r\n<p><strong>Question 1:<\/strong> <span style=\"font-weight: 400\">Consider the following statements: <strong>(UPSC Prelims 2025)<\/strong><\/span><\/p>\r\n<ol style=\"list-style-type: upper-roman\">\r\n\t<li><span style=\"font-weight: 400\"> It is expected that <\/span>Majorana 1<span style=\"font-weight: 400\"> chip will enable quantum computing.<\/span><\/li>\r\n\t<li><span style=\"font-weight: 400\"> Majorana 1 chip has been introduced by Amazon Web Services (AWS).<\/span><\/li>\r\n\t<li>Deep learning is a subset of machine learning.<\/li>\r\n<\/ol>\r\n<p><span style=\"font-weight: 400\">Which of the statements given above are correct?<\/span><\/p>\r\n<p><span style=\"font-weight: 400\">a) I and II only<\/span><\/p>\r\n<p><span style=\"font-weight: 400\">b) II and III only<\/span><\/p>\r\n<p><span style=\"font-weight: 400\">c) I and III only<\/span><\/p>\r\n<p><span style=\"font-weight: 400\">d) I, II and III<\/span><\/p>\r\n<p><strong>Ans: (c)<\/strong><\/p>","protected":false},"excerpt":{"rendered":"<p>Quantum computing is a type of computing that utilizes quantum mechanics principles, such as superposition and entanglement, to perform operations on data.<\/p>\n","protected":false},"author":6,"featured_media":20182,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[239],"tags":[743,40],"class_list":{"0":"post-6150","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-quest-level-4","8":"tag-quantum-computing","9":"tag-quest"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/6150","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/comments?post=6150"}],"version-history":[{"count":1,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/6150\/revisions"}],"predecessor-version":[{"id":19914,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/posts\/6150\/revisions\/19914"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/media\/20182"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/media?parent=6150"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/categories?post=6150"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/upsc-exam\/wp-json\/wp\/v2\/tags?post=6150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}