Quantum Computing

Quantum Computing is a branch of computing that deals with the creation of computers that use the quantum theory to explain how energy and matter behaves on the atomic and sub atomic level. Quantum computers are different from the classical computers that utilize binary where information is processed in bits that can only be either 0 or 1 and a qubit can represent 0, 1 or both at the same time through a quantum principle known as superposition. This makes quantum computers to be capable of solving computations that are almost impossible for the classical computers. 

Key Concepts of Quantum Computing 

1. Qubits:  The basic unit of information in a quantum computer is known as qubit. Unlike conventional bit which can only have two states either 0 or 1 but can exist in both at the same time. This property makes it possible for quantum computers to deal with large volumes of data at a given instance making it more convenient to employ for some computations.
2. Superposition:  Superposition is a quantum mechanical principle which postulates that a quantum system can be in a state that is the combination of two or more states at the same time. Superposition in quantum computing is the phenomenon by which states of qubits can exist as both 0 and 1 at the same time that is quantum computers can perform many operations at once. 
3. Entanglement:  One of the famous quantum concepts is entanglement which is a property that makes two or more qubits to be in a relationship where the state of one qubit is dependent on the state of the other irrespective of the distance between them. Such a property allows several couplings of the qubit pairs to take place, and if applied, can result in extremely efficient quantum operations.
4. Quantum Interference:  In quantum computing quantum interference helps in increasing the probability of right solutions to a problem while reducing the probability of wrong solutions. Quantum algorithms exploit interference with the help of superposition and entanglement of qubits and are therefore more efficient than classical algorithms. 
5. Quantum Gates:  Quantum gates are the basic elements of quantum circuits as same as the classical gates in the classical circuits. These gates are used to manipulate the qubits by ways of rotation, entanglement, and superposition; which are all used to perform the quantum algorithms.
6. Quantum Algorithms: Quantum algorithms are designed with an aim of exploiting the properties of quantum mechanics. Some of these are Shor’s algorithm to factorize large numbers (which has implication on cryptography) and Grover’s algorithm to search through unsorted list faster than the classical algorithms. 

Potential Applications of Quantum Computing 

1. Cryptography: Quantum computing can become the main threat to modern cryptography. Some of them are Shor’s algorithm which can break common encryption systems like RSA by factoring large integers. This has made the researchers to come up with quantum resistant cryptographic techniques to ensure security in future where quantum computers are in fashion. 
2. Drug Discovery and Material Science: Quantum computing has the potential to revolutionise drug development and material science through the ability to simulate quantum level chemical interactions. These are computations that are virtually impossible to do with classical computers and could have application in such fields as medicine or material science. 
3. Optimization Problems:  Optimization is a problem which requires the use of large datasets and a number of variables to arrive at a solution and this is where quantum computing comes in handy. Some of them are supply chain management, portfolio management, traffic management and many more where quantum computing can outperform the classical computing system. 
4. Machine Learning:  Quantum machine learning is a relatively new area of research which aims at investigating the potential of quantum computers for machine learning. Such technologies as quantum computers could help process and analyze the data faster and thus help to train models faster and more effectively. 
5. Climate Modeling and Simulation: Quantum computing can enhance climate modelling as it can study various systems which are linked with a large number of variables. This could result to better estimations of climate change and come up with ways of reducing its effects. 
6. Artificial Intelligence: Currently, quantum computing has the ability to increase the development of artificial intelligence as it will enable the handling of big data and also improve the AI algorithms. This could yield to the development of more sophisticated AI systems that can address problems that are unsolvable by today’s computing systems. 

Advantages of Quantum Computing 

1. Speed and Efficiency:  These quantum computers can perform some tasks quicker than a traditional computer can with those tasks. This speed and efficiency could change industries that involve a lot of calculations including cryptography, material science and artificial intelligence. 
2. Parallelism:  Quantum computers are able to consider many options at once because the state of qubits is the superposition. This parallelism helps quantum algorithms looking for the solution set in the exponentially large solution space hence why quantum algorithms are applicable in optimisation and searching.
3. Solving Intractable Problems:  It is believed that quantum computing can tackle certain challenges which are practically unthinkable for today’s classical computers, including factoring large numbers, simulating quantum systems, and optimization of large and highly-parametrized systems. 
4. Enhanced Security:  Quantum computing is a threat to the current cryptographic systems but at the same time it provides a ground for new quantum cryptographic methods like QKD which is theoretically unbreakable. 

Challenges and Limitations of Quantum Computing 

1. Technical Complexity: Quantum computers are very hard to construct and even harder to maintain. Qubits are very much susceptible to the external environment and any form of disruption can cause them to lose their coherence and therefore introduce errors in the computation. Error corrected quantum computers that are stable are still in the process of being developed. 
2. Scalability:  One of the biggest challenges is the ability to build more qubits and keep them coherent and entangled. Quantum computing devices cannot currently have a large number of qubits that are needed for performing useful, practical computations and how to achieve this remains an active area of research. 
3. Error Rates and Decoherence:  The problem with quantum computers is that they are noisy and their qubits decohere, that is they lose their quantum state due to interaction with the outside world. The techniques for error correction are necessary due to these errors, however their implementation results in an increase in system complexity. 
4. Limited Algorithms:  Despite the hype surrounding quantum computers there are only a handful of quantum algorithms that have shown improvement over classical algorithms. there is ongoing work done in the design of new quantum algorithms which are capable of exploiting all the possibilities of quantum computing. 
5. Resource Intensive:  Quantum computers are very sensitive and have to be operated in special conditions for instance very low temperatures. Such conditions require a lot of infrastructure and, therefore, a lot of resources and money to sustain. 

Conclusion 

Thus, Quantum Computing could be defined as a branch of computing that is aimed at creating computers that work according to the laws of quantum mechanics. It is a revolution in computing as it provides the possibility of solving hitherto unsolvable problems by conventional computers. In a direct manner, operational features in qubits such as superposition and entanglement allows a quantum computing system to perform multiple operations at once and solve problems in less time than it would take in classical computing. Quantum computing is one of the most exciting technologies of our time with applications ranging from cryptography to drug design to artificial intelligence. However, quantum computing is not without its problems: the most significant of these being the technical problems of scaling up the system, and the challenge of managing errors. With more and more investment in research and development quantum computing could redefine many sectors and could produce advancements in science, technology and more.