Qubits, Superposition, and Entanglement: A Guide to the Quantum World

 

Quantum computers use qubits to solve intractable problems that even the most powerful supercomputers cannot perform. (Image:BBC)

Introduction: Quantum technology is a pathbreaking field which applies the laws of quantum mechanics to create devices with exceptional capabilities far exceeding that of classical physics. Unlike classical physics that governs on physical phenomenon, including mechanics, thermodynamics, and electromagnetism, quantum mechanics leverages the behaviour of matter and energy at the subatomic level.

Foundational Principles of Quantum Mechanics:

• Superposition: It is the phenomenon which describes the ability of a particle to exist in multiple states at the same time. This is the basis of qubit (quantum bit) which can be both 0, 1, or a combination of both, differing from classical bit, which is either a 0 or a 1. It allows a quantum computer to perform multiple calculations simultaneously, thus enhancing its processing power.
• Entanglement: This is the tendency of two or more particles to become linked in such a manner that their quantum state cannot be defined independently, even if they are far apart. It enables the creation of highly secure communication networks and an interconnected system of quantum computers.
• Quantum Tunneling: It is a strange phenomenon that enables a particle to pass through an energy barrier which it would not have the energy to overcome otherwise. This is due to the wave-particle duality of matter. Application of this principle is found in technologies like scanning tunneling microscopes.

Applications of Quantum Technology:

• Quantum Computing: Quantum computers use qubits to solve problems that even the most powerful supercomputers are unable to perform.

1. Optimization of Problems: Quantum computers look for the best possible solution from a massive number of problems which can help in optimizing traffic flows, scheduling flights, or designing coplex logistics networks.
2. Material Science and Drug Discovery: By simulating the behaviour of molecules and atoms at a quantum level, quantum computing holds the potential to discover new, more efficient materials, better battery systems, and groundbreaking new drugs.
3. Artificial Intelligence (AI): Quantum computing enhances machine learning algorithms by training AI systems more efficiently.

• Quantum Sensing and Metrology: Quantum sensors use quantum effects to identify minute changes in magnetic fields, gravity, or time. Their applications include:

1. Medical Imaging: New-generation MRI scanners offer unprecedented resolution, allowing for earlier and more accurate disease diagnosis.
2. Navigation: Quantum-enabled navigation systems can deliver GPS-like accuracy without relying on satellites, critical for submarines, autonomous vehicles, and military applications.
3. Earth Science: High-precision sensors can detect underground geological structures or monitor changes in the Earth's magnetic field, helping in earthquake prediction.

• Quantum Communication and Cryptography:

1. Quantum Key Distribution (QKD): It allows two parties to create and share an encryption key encoded in the quantum state of particles. Any third-party attempt to tamper with the key changes the quantum state, alerting both the sender and the receiver, making QKD the most secure form communication till now.
2. Post-Quantum Cryptography (PQC): It focuses on developing new algorithms designed to be secure against attacks from both classical and future quantum computers.

• Quantum Materials: These are substances which exhibit unique quantum properties on a macroscopic scale. Quantum materials are the building blocks of the quantum revolution, from the supercomputing circuits in the quantum computers to the quantum dots used in display and solar cells.

Significance of Quantum Technology for India:

• Communication: Secure communication through QKD and PQC holds immense potential for the military, including creating highly accurate navigation systems and stealth technologies.
• Healthcare: Quantum computing can revolutionize drug delivery and medical research by simulating complex molecular interactions, resulting in the creation of new medicines.
• Finance: Quantum computers can refine complex financial models, enabling better risk analysis, fraud detection, and high-frequency trading strategies.
• Logistics and Manufacturing: Quantum algorithms can decipher intricate problems to streamline supply chains, reduce costs, and increase efficiency in the manufacturing process.
• Energy and Climate: Quantum technology can assist in the discovery of new materials for more efficient batteries and solar cells, and in formulating more accurate climate models to help with disaster management and sustainable development.

Challenges for India:

• Lack of a robust indigenous ecosystem for quantum hardware design leads to heavy reliance on foreign sources for critical components and infrastructure. A report from the Office of the Principle Scientific Adviser illustrates that while Indian companies are developing quantum computers, the essential qubits are often fabricated abroad.
• Deficit of specialized and expensive infrastructure such as cryogenic refrigeration systems to maintain qubits at near-absolute zero temperatures.
• There is a mismatch between academic training and the practical skills required by the industry. The curriculum needs to be better aligned with changing demands of the industry and the larger economy.
• The overall contribution of domestic private sector to R&D is subpar compared to countries like the US and China, where private investment incentivizes innovation.
• Lack of clear standard for quantum hardware, software, and communication interfaces leads to ambiguous policymaking and problems in regulation.

Major Initiatives Taken:

• National Quantum Mission (NQM): Approved by the Union Cabinet in 2023 with a substantial outlay of ₹6,003.65 crore for the period 2023-24 to 2030-31. Its objectives include:

1. Developing intermediate-scale quantum computers, using various platforms like superconducting and photonic technologies.
2. Establishing secure quantum communication links, including a satellite-based quantum-secured communication between two ground stations over 2000 km within India and inter-city Quantum Key Distribution (QKD) over a similar distance using existing optical fibre infrastructure.
3. Designing highly sensitive devices like magnetometers and gravity sensors, along with atomic clocks with better stability for applications in precision timing, navigation,and fundamental science.
4. Supporting the design of new quantum materials, such as superconductors and novel semiconductor structures, which are the building blocks for fabricating quantum devices.

• Karnataka has announced a ₹1000 crore Quantum Mission to build a $20 billion quantum economy by 2035.
• The DRDO is leading projects developing quantum-safe cryptographic algorithms to protect India's critical digital infrastructure from future quantum attacks.
• The Ministry of Electronics and Information Technology (MeitY) has founded a Centre of Excellence in Quantum Technology and secure quantum communication testbed in Chennai, demonstrating a clear push for public-private collaboration to accelerate the commercialization of quantum solutions.
• The latest MoU between QIS Educational Institutions and Quantum Research and Centre of Excellence (ORACE) seeks to boost joint R&D and talent development.

Way Forward:

• Integrate quantum science, quantum computing, and quantum engineering into the undergraduate and postgraduate curricula.
• Create a network of specialized training programs, boot camps, and fellowships which provide domain knowledge and practical skills.
• Foster a robust domestic supply chain for critical quantum hardware components, including incentives for the manufacturing of specialized lasers, high-purity materials, and cryogenic systems,
• Incentivize the private sector to invest in quantum R&D through tax incentives, grants, and subsidies.
• Promote Public-Private Partnerships (PPPs) to leverage the unique strengths of each sector.
• Establish a national regulatory body to address the ethical implications of quantum technology, including its impact on data privacy and national security.

Conclusion: India's approach to quantum technology is multi-faceted and well-funded, combining a long-term national mission with targeted initiatives from state governments and research agencies, all aimed at creating a self-sufficient and globally competitive quantum ecosystem.