Knowledge Nugget | Quantum Computing: What is the new research and why does it matter?

2. Some of these special properties happen to be “quantum entanglement” and  “superposition.” Scientists have used these to build powerful quantum computers which can perform certain very complex computations in an efficient manner.

What are Quantum Entanglement and Superposition? 

3. Quantum Entanglement is a remarkable property of the quantum world in which two particles, after undergoing an interaction, get “linked” (or entangled) together in such a way that they begin to behave like one single system. When qubits become entangled, their individual states have no independent meaning; you can only describe the system as a whole.

4. Measuring certain properties of one reveals information about corresponding properties of the other, irrespective of the distance between the two — a phenomenon Albert Einstein dubbed “spooky action at a distance.”

5. Superposition is the ability of quantum particles to exist in multiple states at the same time. The Heisenberg uncertainty principle, part of the bedrock of quantum mechanics, tells us that certain pairs of properties — such as position and momentum — cannot both be known exactly at the same time. This fuzziness gives rise to superposition, where a quantum system exists in a blend of states simultaneously. 

What is Quantum Computing?

6. At the smallest scales (quantum scales- the microscopic realm of atoms and subatomic particles), nature behaves differently from our everyday experience. 

7. As per California Institute of Technology website, quantum computers share some properties with classical ones. For example, both types of computers usually have chips, circuits, and logic gates. Their operations are directed by algorithms (essentially sequential instructions), and they use a binary code of ones and zeros to represent information.

8. Both types of computers use physical objects to encode those ones and zeros. In classical computers, these objects encode bits (binary digits) in two states— e.g., a current is on or off, a magnet points up or down.

9. Quantum computers use quantum bits, or qubits (the basic unit of information in quantum computing, acting as the quantum equivalent of a traditional computer bit), which process information very differently.

10. While classical bits always represent either one or zero, a qubit can be in a superposition of one and zero simultaneously until its state is measured.

11. The implications are extraordinary. As qubits interact, the number of possible states grows exponentially. With just 300 quantum particles, the number of possible configurations exceeds the estimated number of atoms in the observable universe. 

12. This is not simply about doing today’s calculations faster. It is about opening entirely new computational possibilities. Such capabilities could transform areas as diverse as drug discovery, materials science, logistics, financial modelling, climate forecasting and secure communications.

Why are entanglement and superposition difficult to maintain? 

1. The challenge is to harness the potential of the quantum states for use in computing. Quantum states are exquisitely fragile. Tiny disturbances like thermal vibrations, stray fields, or cosmic rays can collapse superpositions and entanglement. 

2. The entangled state, for example, disintegrates very quickly on interaction with the external environment, a phenomenon known as decoherence. 

3. Sometimes, entanglement vanishes abruptly, too, even before the normal disintegration takes place. Scientists call this condition “entanglement sudden death.”

4. Today’s qubits remain coherent for just 10⁻⁵ to 10⁻⁴ seconds before errors arise, whereas classical memory holds data intact for milliseconds to years.

5. This weakness creates a problem for quantum computing. The integrity of the calculations becomes doubtful. Scientists have tried to deal with this challenge by carrying out repeated corrective interventions that delay decoherence. 

6. To combat the issue, researchers cool qubits to near absolute zero, isolate them in vacuum, and use error-correction schemes that trade many physical qubits for one robust “logical” qubit. 

7. These logical qubits can detect and correct small quantum errors on the fly, preserving the fragile quantum information long enough for useful computation. But these repetitive interventions have their own side-effects. They are costly, and can introduce errors of their own.

8. This is where the research team of Urbasi Sinha, group leader of the lab at RRI, has achieved a breakthrough. Instead of repetitive operations, her team has developed a new technique that deals with decoherence in this context through a “single-shot operation.”

What is a single shot fix significant? 

1. Raman Research Institute scientists found that a single, well-timed operation, not repeated fixes, can delay or prevent quantum entanglement from collapsing in this context. Timing itself becomes a new control tool, offering a simpler way to protect fragile quantum states used in computing, alongside existing error- correction methods.

2. Depending on the instant when the operation is carried out, this operation can delay decoherence and entirely avoid sudden death.

3. Applied at some other instant, this operation can even hasten decoherence, though it is not an outcome that is scientifically desirable. This operation, therefore, gives scientists greater control over the different possibilities.

4. Sinha, a senior professor at RRI, said her experiments presented a proof of concept, something that has relevance to the problem of decoherence, rather than a complete solution.

5, “We are not claiming to have solved decoherence or replaced quantum error correction, rather the work identifies timing itself as another control parameter that future quantum processors could exploit alongside better materials, better gates, and error-correction protocols,” she said.

6. “Our experiment shows that one does not always have to fight decoherence with long sequences of corrective operations. The timing of a single local gate can redirect the entanglement trajectory and extend the regime over which the state remains useful,” she said.

7. It would need to be tested out by different quantum computing systems to see how advantageously it can be applied in different environments. The results of experiments by Sinha’s team have been published in a paper in the American Physical Society’s Physical Review A.

BEYOND THE NUGGET:  National Quantum Mission (NQM)

NQM official logo.

1. Launched at a total cost of Rs.6003.65 crore from 2023-24 to 2030-31, aims to seed, nurture and scale up scientific and industrial R&D and create a vibrant & innovative ecosystem in Quantum Technology (QT). 

2. It focuses on four key domains or verticals, i.e. Quantum Computing, Quantum Communication, Quantum Sensing & Metrology, and Quantum  Materials & Devices.

3. The mission objectives under NQM:

(i) Developing intermediate-scale quantum computers with 50-1000 physical qubits in 8 years in various platforms like superconducting and photonic technology.

(ii) Satellite-based secure quantum communications between ground stations over a range of 2000 kilometers within India

(iii) Developing magnetometers with high sensitivity in atomic systems and Atomic Clocks for precision timing, communications, and navigation.

(iv) Design and synthesis of quantum materials such as superconductors, novel semiconductor structures, and topological materials for the fabrication of quantum devices.

(v) Development of single photon sources/detectors, and entangled photon sources for quantum communications, sensing, and metrological applications.

Post Read Question

Which of the following statements with regard to the National Quantum Mission (NQM) is/are correct? (UPSC CSE, 2026) 

1. It aims at developing intermediate-scale quantum computers with 50-1000 physical qubits.

2. Its implementation includes setting up of four Thematic Hubs (T-Hubs) in academic and national R&D institutes across India.

Select the answer using the code given below:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer: (c)

(Sources: caltech.edu,  Knowledge Nugget: India’s first quantum facility in Andhra Pradesh’s Amravati — what UPSC aspirants must know, The universe, the atom, and a cat both dead and alive: Understanding Quantum Mechanics, National Quantum Mission: How does India seek to harness the potential of quantum technology) 

🚨 Click Here to read the UPSC Essentials magazine for August 2026. Share your views and suggestions in the comment box or at manas.srivastava@indianexpress.com🚨 

Subscribe to our UPSC newsletter. Stay updated with the latest UPSC articles by joining our Telegram channel – Indian Express UPSC Hub, and follow us on Instagram and X