# Quantum Information and Computation

Dear Reader!

I am going to describe How Quantum Computing is going to be important in coming years and How India is Prepared for that. As you read, you will get to know about What is Quantum Computing, Why we should focus on QC, What it takes to develop a Quantum Computer Machine**, **Paradigms and Applications in QC, Future of QC, Myths and fun facts related QC, Who are early industry adopters and related fields. You will also get to know how we are taking it from Turing Machine/Classical Computing.

Quantum Computing mostly studied theoretically, claims to turn the table when brought to main stream computing. It is exponentially fast and secure. With past two decades, exhaustive research had been carried to understand and implement principles of QC. Recently, the focus is shifted more towards Quantum cryptography, communication and speedups. It is likely that, by coming 20–30 years, we would see some more advanced quantum cryptographic methods that must be secure than today’s methods. This came to be possible because of the intrinsic property of atomic particles when studies with quantum mechanics. In short, if we are able to determine a particle spin in our place, we are also able to determine the spin of far distant sub-atomic particle. However, this used to be also a point of confusion, Einstein said as “Spooky behavior of particles” as it was breaking classical physics laws. But in recent year, 2017 specifically, china achieved the farthest quantum teleportation/communication. To bring you a feel how big we are talking about, then it is suitable to compare that only 250 qubits can achieve that much supremacy that could bring by classical bits equivalent to 10⁸⁰. In fact the difficulty to break your password which could be measured on How Secure is my password will be of no value when introduced QC into the play. Secondly, talking about how this can change our daily lives? This can be answered with only jargons that are going to be affected when introduced with quantum speedups in ML and AI applications. Smart Healthcare, IoT, Smart mobility, E-Governance, Space Technologies, Gaming and many other main stream applications which can be benefitted by QC. How India is prepared to that, Leading among other countries, as Indian Govt. has announced 8000cr budget for 5 years, under National Mission on Quantum Technologies and Applications (NM-QTA)

QC is one of the multi-disciplinary study which evolves from Physics and Computing. Utilizing the quantum mechanics in achieving the quantum properties with computers. In other words, we bring the quantum theory to study quantum bits (analog to classical bit which can take 0 or 1). Qubit can take any value until decided. Qubit is the fundamental measuring criteria for quantum information. In QC, a state can be in superposition which allow to perform computation not only on one state on multiple states at same time. Analog to classical computing when you can perform operation with 3 bits, then you can have only one state between 0 to 7, however, when you have a qubit, you can have superposition of all 8 values. This is the speedup where you can perform operations on all 8 states at same time. However, the way quantum entanglement works, in quantum physics, in any one of the entanglement pairs when you discover or observe one of the subatomic particle then the entanglement is collapsed (Discovered by Einstein-Bell Theory, Delayed choice quantum eraser experiment), the same way, when we measure the superposition state of the qubit, it will collapse to one of its states. Thus ensuring we will be getting only one answer in the end. That is, when performing operations we may get all states in between however once the obserservations are realized the final state or the results are carried out, then our entanglement collapses. The interference effect which was observed by Double Slit Experiment which enables us to perform calculations on superposition of states. Without going into deep, there is representation for quantum states called as Dirac’s Notation. Ket (column vector) and Bra (row vector) and their inner products as bra-ket and ket-bra.

In order to answer why do we should focus on quantum computing, we shall understand how we will be using the technology in near future. It is very sure that you will not see quantum computers for commercial or domestic usages. However, the large scale analytics and computations, the computers which handle terabytes of data in daily basis shall be accelerated with quantum computation. Additionally, it is not likely to just replace commercial computers with quantum computers, however, they will run parallel to each other. A superficial plan setup for future quantum computers can be understood as MNCs having a centralized quantum computer which will be handling each user’s computation on a separate quantum processing unit, which could reduce cost of devices, increase speed and help companies to provide better insights. A recent announcement by D-Wave to commercialize quantum cloud called Leap which is specially for businesses. Additionally, in the race, A Chinese company Baidu also announced in quarter 3 of the year 2020 to implement quantum cloud called as quantum leaf (QaaS — Quantum As a Service)for business analytics and real world game simulations for Developers. It has been more than 20 years that quantum computing is being studied by researchers. In fact, the researchers are more interested in Post Quantum Phase which would bring change in the present computing. The bottom line why we should focus on quantum computing is because of quantum communication, security, speedups, and for Industry 4.0. It is expected to develop benchmarking tools and products which can disrupt the way we do computation today. At present, the potential developments can be seen in Chemistry, Medical Science, Mathematics, Aerodynamic real world simulations, Control and Optimization problems in machine learning and Risk minimization. Companies in line to win race in quantum computation are D-wave Ocean, Google quantum cirq, IBM qiskit , Microsoft QDK, Rigetti, Xanadu, ETH Zurich.

How do we build quantum computer machine and how do we implement it? Designing and Setting up quantum system in a lab is extremely difficult. The environment is created such that the lab room is made favorable with temperature, pressure and proper cooling along with infrastructure is required. On paper, apart from considering inner physics, the computer logics are build by quantum circuits, gates and measurements. We devise analog quantum gates as we have in classical computers. The important NOT Gate, in classical world just works as inverter for the input. In quantum it is represented by matrices in Dirac’s Notation. On contrary to the classical digital logics, we devise 5 different types of single qubit gates namely, Bit Flip, Phase Flip, Pauli y, Hadamard Gate and S-Gate. With respect to 2 qubit Gates, for example XOR gate, the quantum alternative is Controlled not which is more advanced wrt classical XOR because along with XOR you also get inputs as the outputs which makes it reversible operations and hence satisfies the quantum supremacy. In addition, we can show that every function *f *can be described by a reversible circuit. Quantum circuits can perform all operations that can be done classically.

The potential applications which are expected to emerge by later decades is firstly, smart mobility systems (quantum annealing) which works in finding best routes for a task, optimization problems and shortest path problems. It can also help in modelling better classification and regression tasks for ML. Secondly, there is a huge research in past as well as current for quantum communication which enables faster connectivity. Which enables for non-breaking cryptographical methods. Apart from this, other applications comprises of Information Retrieval and Search Engines, Knowledge Representations, Real world simulations (In fact, people are generating single player simulation game worlds using quantum computers, for example Minecraft). The quantum speedups are expected to learn models at better rates. Learn complex models and algorithms which used to be considered time taking can be solved in seconds. Remember, in mankind history in 2005 DARPA race of autonomous vehicles or Defeating world champion in 1997 by brute force generation of chess

states. Quantum Computing is able to generate millions of states within seconds whether it is multiple routes for Autonomous car championship or generating state spaces for chess by solving heuristics faster.

What is the future? Be it any vertical in which computer development and computerization is happening, from banking to industrial, from manufacturing to smart city projects, everything require faster output and decision making. Faster decision making comes to play important role in smart mobility and autonomous vehicles. What if there can be a speedup in communication which we do today. It will bring remarkable achievements to human if we are able to achieve in mainstream applications. In security, Professor Dr Sohini Ghose mentioned that “Quantum offers a way to encrypt information that can never be hacked, no matter how good the hackers are.” With a concluding note, lets understand the facts about quantum computing:

- QC can break your password in seconds which could take billion years for a classical computer in brute force.
- Researchers claim that even if quantum computers could break your text based passwords, but future with qc is secure and non-tampered.
- QC are a great solver for managing traffic controls and path problems.
- In the age of big data quantum computing is a need of hour.
- Quantum Computers work at -273.13° Celsius.
- Reduces power consumption.
- Google and IBM are competitors, the former is claiming to get quantum supremacy and the latter one is claiming to deliver quantum computing services commercially to businesses.

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