Over the past few decades, a lot of research and advancement has been going on how to increase the speed of processing of data and its storage.
Scientists and engineers are working on a two-level quantum system which can take both the values (0, 1).
What is Qubit?
What is Quantum Computing?
What is Quantum Superposition and Entanglement?
What are Quantum Algorithms and Quantum gates?
Different stages of quantum computing
Where do we stand in world in Quantum computing?
History: -
The spark of quantum computing was brought by Richard Feynmann in 1981 when he discussed that Classical computers cannot simulate the vast quantum world. In 1994 Peter Shor developed the 1st quantum algorithm which could factorize large integers quicker than a classical computer can do. In 1998 1st 2 qubit quantum computer was developed which could solve quantum algorithms. In 2017 IBM presented 1st commercially usable quantum computer which can be simulated from anywhere.
Recently Google and China have claimed to reach up to 56 qubits.
Quantum Computing: -
Quantum computing uses the weirdness of quantum mechanics to solve tedious calculations which cannot be done by simple classical computers.
It works on a two-level system called Qubit. The input data is static but during the processing the data doesn’t remain static but exist in multistate before observation and each state has their probability of equal existence until the measurement where a single state remains.
Qubits vs Classical bit: -
A qubit is a two-level system also known as Quantum bit. It is the quantum analog of a classical bit i.e. (0, 1). It can take value |0>, |1> or linear combination of both states.
A classical bit is a static bit whereas a quantum bit is a dynamic bit. Due to its this property, it is widely used in solving calculations of algorithms which classical bit will take millions of years to solve and it can solve in seconds.
Bloch Sphere And Hilbert Space: -
Bloch sphere is a geometrical representation of the pure state space of a two-level quantum mechanical system (qubit), named after the physicist Felix Bloch. It is a unit 2-sphere, with antipodal points corresponding to a pair of mutually orthogonal state vectors. The north and south poles of the Bloch sphere are typically chosen to correspond to the standard basis vectors |0> {\displaystyle |0\rangle }|| and |1>{\displaystyle |1\rangle }, respectively.
A Hilbert space is a vector space equipped with an inner product, an operation that allows defining lengths and angles. Hilbert spaces are complete, which means that there are enough limits in the space to allow the techniques of calculus to be used.
Hilbert spaces support generalizations of simple geometric concepts like projection and change of basis from their usual finite dimensional setting.
Quantum Superposition: -
It is a feature of a quantum system due to which it can exist in more than one state at any instant.
Just like a wave two or more quantum states superpose to form another quantum state.
Ψ3= ψ1+ ψ2
A quantum state is a linear combination of basis state represented in Bra-Ket system.
Ψ=a|0> +b|1>
Basis vectors |0> and |1> are orthogonal vectors and squares of coefficients ‘a’ and ‘b’ describes the probability of |o> and |1> states in a quantum state.
a^2 + b^2 = 1
In Schrodinger’s Cat Experiment the probabilities of Cat to be alive or dead are equal so the cat is in a superposition state of dead and alive.
Quantum Entanglement : -
It is a quantum weird phenomenon in which a group or pain of particles are generated whose quantum states are not independent and interact even when are at million miles apart in space. Any change in quantum state one of the particles bring the change in the other part of the pair.
Measurement of properties like momentum, electron spin, position, polarization etc. resembles in the entangled duo.
Researchers are working on technology that enables the transfer of qubits between any two points. Such quantum bits can be |0> and |1> at the same time, and are entangled.
Entanglement allows improved coordination between distant sites. This makes it extremely suitable for tasks such as clock synchronization.
Entanglement is inherently secure. Any two quantum bits with maximum entanglement, have no any share of rest environment in that entanglement. This makes entanglement uniquely suitable for applications that require security and privacy.
Quantum Measurement: -
In Quantum Physics or Computing Measurement is an important process in which the quantum state in the linear combination of basis states resolves into either of the basis states i.e., |0> or |1>.
Before measurement a quantum particle can exist in millions of possible combinations of basis states but during measurement it gives the exact one possible outcome.
Quantum Algorithm and Gates: -
Quantum algorithms are set of rules which runs on a realistic model of quantum computing, using quantum circuits.
Classical algorithms are finite sequence of instructions, or a step-by-step procedure for solving a problem, where each instruction can be performed on a classical computer. Likewise, a quantum algorithm is a step-by-step procedure, where each of the steps can be performed on a quantum computer.
What makes quantum algorithms superior is that they are able to solve some problems faster than classical algorithms because of quantum superposition and quantum entanglement that allows them to be efficiently simulated on classical computers.
Quantum logic gate is a basic quantum circuit which works on a small number of qubits. They are the building units of quantum circuits.
Quantum gates are basically matrices(operators) which work on eigen vectors i.e., quantum states and gives a scalar value called eigen values. They are reversible unlike most classical logic gates.
Some of the important logic gates are: -
Pauli -X gate: - It is a bit flip gate. |0> -X- |1> |1> -X- |0>
Pauli -Z gate: - It is a phase shift gate. |0> -Z- |0> |1> -Z- -|1>
Hadamard gate: - This gate creates the equal probabilities of 0 and 1.
|0> -H- = (1/2)^2 |0> + (1/2)^2 |1> |1> -H- = (1/2)^2 |0> - (1/2)^2 |1>
CNOT gate: - This gate operates on two qubits in such a way that the first qubit serves as a control and other qubit serves as target.
Swap gate: - It performs half-way of a two-qubit swap. Any many-qubit gate can be constructed from only swap and single qubit gates.
Different Stages of Quantum Computing: -
- Quantum Software and circuit (Quantum Algorithms)
- Classical Software and circuits
- Quantum Program Compiler
- Classical Control Hardware
- Quantum Hardware
How A New Quantum World Will Look?
A quantum world with quantum computers working on a two-level system will change the way we work. We will be much faster in calculations and data processing; the data privacy and security will be at the next level making it almost impossible for hackers to access data of individuals. The quantum properties like entanglement and superposition alive the hopes of space travel and fast transfer of information. Other than data processing quantum bits would be capable of simulating molecular bonds performing rapid searches of complicated databases or factorizing large numbers very quickly. Quantum computing will modify every field from healthcare to security, weather forecast and disaster management. It can be understandable
Where Do We Stand In Quantum Computing?
Different big companies like IBM, Google, Nasa are working in development of quantum computing technologies. IBM has its own quantum computing environment called Qiskit which can be simulated from any corner of the world by classical computers.
In India Quantum Computing is yet to advance and only researches on quantum computing are going on. The Department of Science & Technology (DST) has set up QuEST or Quantum-Enabled Science & Technology (QuEST) at an institute in Hyderabad. As indicated in the Union Budget 2020, quantum technology is opening up new frontiers in computing, communications and cyber security with widespread applications. The aim is to boost research for commercial applications in quantum technologies. Skills in quantum computing need to be developed as objects become smarter and computers become faster.
Under the leadership of a profound Scholar Researcher and Quantum Hardware expert Dr. R. Vijay Raghavan research on Quantum computing and work on Quantum hardware is going on in TIFR. (The only established experimental group in India which is working on superconducting quantum devices known as Quantum Measurement and Control (QuMaC) Lab in TIFR headed by him).
This group started in Dec 2012, became fully operational in Jan 2014 and has already several important publications which include the development of a new type of ultra-low noise broadband amplifier for quantum measurements and a novel three-qubit quantum processor called the “trimon”.
Conclusion: -
Quantum computing promises many possibilities and a new vision to the world. Although no one completely understands the quantum algorithms and how a quantum computer to be programmed. Also a little knows how it works and processes the data, but still the researches on it makes us await a new vision to visualize and see the quantum world. The days are not far when quantum computing and quantum physics will change how the world behave and may it bring new hopes for us in knowing this quantum world in a better way.
Thanking you for reading…!!