## “Nature isn’t classical, dammit, and if you want to make a simulation of nature, you’d better make it quantum mechanical”,

## said sir Richard Feynman in a talk in 1981.

Quantum computing has emerged as a revolutionary field in computer science, promising unparalleled computational power by leveraging quantum mechanics principles. Unlike classical computers that use bits to represent either 0 or 1, quantum computers use quantum bits or qubits, which can exist in multiple states simultaneously through superposition and entanglement. To realise the full potential of quantum computing, the integration of superconductors has become a pivotal pursuit in the quest for higher operating temperatures and increased coherence.

## Tracing the path through historical milestones

The foundation of quantum computing lies in the development of quantum mechanics, which began with Max Planck’s revolutionary work in 1900s. Planck proposed the concept of quantised energy levels, where energy is emitted or absorbed in discrete units called “quanta”.

In 1924, Louis De Broglie proposed the wave-particle duality theory, suggesting that particles like electrons could exhibit both wave like and particle like behaviours. This concept was experimentally verified in the famous double slit experiment by Clinton Davisson and Lester Germer in 1927, providing experimental evidence for the dual nature of particles.

Werner Heisenberg formulated the uncertainty principle in 1927, asserting that certain pairs of physical properties, such as position and momentum, cannot be precisely measured simultaneously. This principle fundamentally challenged classical determinism and became a cornerstone in quantum mechanics.

In 1926, Ervin Schrödinger developed the wave equation, a mathematical framework that describes the behaviour of quantum systems as wave functions. This equation allowed physicists to model and predict the probabilities of quantum states, providing a profound understanding of quantum mechanics.

In 1981, physicist Richard Feynman proposed the idea of using quantum systems to perform computations far more efficiently than classical computers. However, it was Davis Deutsch who laid the formal foundation for quantum computing with his concept of a universal quantum Turing machine in 1985. Deutsch demonstrated that a quantum computer could efficiently simulate any physical process described by quantum mechanics.

In 1994, mathematician Peter Shor devised a quantum algorithm that could factor large numbers exponentially faster than the best-known classical algorithms. Shor's algorithm demonstrated the immense potential of quantum computing in breaking classical cryptographic schemes. In 1996, Lov Grover developed Grover's algorithm, which efficiently searches an unsorted database, providing a quadratic speedup compared to classical search algorithms.

In the late 20th century, experiments confirmed the phenomenon of quantum entanglement, where two or more particles become linked in such a way that their states are inseparably correlated. This entanglement serves as a foundation for quantum gates, which are analogous to classical logic gates, but operate on qubits through controlled transformations.

As of now, quantum computing has seen tremendous progress, with various research institutions and companies developing quantum processors with tens to hundreds of qubits. However, quantum coherence and error rates remain significant challenges that hinder large-scale quantum computations and limit

## Understanding Quantum Computing

Quantum computing harnesses the principles of superposition and entanglement to process vast amounts of information simultaneously. Classical computing operations are represented through binary logic, while quantum operations manipulate qubits, enabling parallel computations and exponential speed-ups for certain algorithms. Quantum gates, such as Hadamard and CNOT gates, form the building blocks of quantum circuits, allowing complex computations beyond classical capabilities.

## The Role Of Superconductors

Superconductors play a pivotal role in quantum computing by serving as the foundation for qubits and quantum processors. These materials exhibit zero electrical resistance and expel magnetic fields below a critical temperature, enabling long coherence times and low error rates essential for preserving quantum states. In quantum computing, superconductors are employed to create and manipulate qubits through quantum gates, facilitating quantum entanglement and superposition. Currently, superconducting qubits operate at cryogenic temperatures near absolute zero to maintain their delicate quantum properties. However, the pursuit of room temperature superconductors remains crucial to realise practical, scalable, and commercially viable quantum computers, eliminating the need for intricate and costly cryogenic systems and revolutionising the landscape of quantum computing

## Room Temperature Superconductors

The potential of quantum computing lies in its practical applicability, which necessitates quantum processors operating at higher temperatures for ease of integration, scalability, and commercial viability. Room temperature superconductors would eliminate the need for expensive and complex cryogenic systems, making quantum computers more accessible and practical for real-world applications.

A room temperature superconductor would revolutionize the field of quantum computing by enabling qubits to function at significantly higher temperatures. The elimination of the cryogenic requirements would simplify quantum computer designs, reduce overhead costs, and open up opportunities for large-scale quantum systems. With room temperature superconductors, quantum computers could be more easily interconnected with classical devices, leading to hybrid computing solutions that leverage the strengths of both quantum and classical computation.

## A Recent Breakthrough

Physicist Ranga Dias announced a groundbreaking achievement in quantum computing at the APS March meeting. His team created a room-temperature superconductor using hydrogen, nitrogen, and lutetium, demonstrating perfect electricity conduction (Nature). Though met with enthusiasm, past research controversies have sparked cautious optimism among experts. Superconductivity had been limited to extreme conditions, but this discovery at 21°C and 1 gigapascal pressure could lead to practical applications like lossless power lines and affordable medical imaging. Some researchers express skepticism due to previous retracted claims from the group. Dias defended the findings and a rigorous peer review process. Confirmation by other labs will be crucial, but commercial interests might limit access to the material (Unearthly Materials).

Recently, two South Korean researchers synthesised LK-99; A potential room-temperature superconductor, a gray‒black solid with a hexagonal structure modified from lead‒apatite by introducing copper. The material was discovered by a team from Korea University and is claimed to function as a superconductor below 400 K (127 °C; 260 °F) at ambient pressure. However, as of July 2023, its superconducting properties have not been confirmed or independently replicated.

The material exhibits strong diamagnetic properties, and the proposed mechanism for superconductivity involves partial replacement of Pb2+ ions with Cu2+ ions, creating internal stress and a superconducting quantum well. The team is awaiting further results from independent teams attempting to replicate their findings.

If LK-99 proves to be a genuine room-temperature superconductor, it could have significant implications for the future of quantum computing. Currently, one of the main challenges in quantum computing is maintaining the delicate quantum states of qubits with low error rates. Superconductors, with their zero electrical resistance and long coherence times, are promising candidates for stable qubits. The discovery of a room-temperature superconductor like LK-99 could potentially eliminate the need for elaborate and expensive cryogenic systems to cool qubits to extremely low temperatures. This would make quantum computing more accessible and practical, paving the way for the development of commercially viable quantum computers that can be integrated into everyday applications. Moreover, room-temperature superconductors might lead to more scalable and robust quantum processors, enabling the construction of larger and more powerful quantum computing systems. This, in turn, could accelerate advancements in quantum algorithms, solving complex problems with unprecedented efficiency and speed.

However, it is crucial to note that the claims of LK-99's superconducting properties have not been confirmed yet, and the material's potential impact on quantum computing remains speculative until independent replication and rigorous peer-reviewed research can validate the findings. The scientific community awaits further results and verification before fully understanding the implications of LK-99 for the future of quantum computing.

## The Future Of Quantum Computing

As researchers continue to make progress in quantum computing, the future seems exciting and full of possibilities. One of the key areas of interest is in developing fault-tolerant quantum computers. Quantum systems are inherently susceptible to errors due to various factors like decoherence and noise. Implementing quantum error correction techniques is crucial for building scalable and reliable quantum computers, capable of sustaining quantum states for extended periods and performing accurate computations.

Furthermore, the quest for more stable and efficient qubits is ongoing. Various physical platforms for qubits, such as superconducting circuits, trapped ions, and topological qubits, are being explored to identify the most promising candidates. Each platform has its advantages and challenges, and research is focused on enhancing coherence times, minimizing errors, and finding novel ways to control and manipulate qubits.

In terms of quantum algorithms, researchers are working to develop new approaches and optimize existing ones. Algorithms like Shor's algorithm for prime factorisation and Grover's algorithm for searching can revolutionise cryptography and database search, respectively. As the field advances, we can expect the discovery of more algorithms that exploit the inherent quantum parallelism to solve complex problems efficiently.

Scalability is a crucial concern for quantum computing. Present-day quantum computers are relatively small and limited in the number of qubits they can handle. Scaling up the number of qubits while maintaining their coherence and error rates is a significant challenge. Quantum error correction, robust qubit designs, and improved quantum hardware are all essential components for achieving large-scale, fault-tolerant quantum computers.

Another important aspect of the future of quantum computing is the development of quantum software and programming languages. As quantum computers become more accessible, user-friendly interfaces and standardized programming languages will be essential for researchers and developers to harness the potential of quantum computing effectively.

The potential applications of quantum computing are vast and diverse. Quantum simulations can revolutionize fields like materials science, drug discovery, and climate modeling by accurately modeling complex quantum systems that are practically intractable for classical computers.

Quantum machine learning could enhance data processing, pattern recognition, and optimization tasks. Quantum cryptography promises unbreakable encryption, ensuring secure communications in a world increasingly reliant on digital technology. Moreover, quantum computing has the potential to revolutionise artificial intelligence (AI). Quantum algorithms for machine learning and optimization could lead to significant advancements in AI research, opening doors to solving complex problems that are currently computationally infeasible.

The future of quantum computing also lies in quantum networking and quantum internet. Building a quantum internet that allows secure quantum communication and quantum teleportation between distant nodes could have profound implications for communication, cryptography, and distributed computing.

However, it is important to acknowledge that quantum computing is still in its early stages, and significant challenges remain. Bridging the gap between theoretical models and practical implementations, mitigating decoherence and noise, and achieving fault tolerance are critical milestones that researchers are actively working towards.

In conclusion, the future of quantum computing holds immense potential to revolutionise various domains of science, technology, and industry.

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