The document discusses quantum computing, providing an overview of classical computers and their evolution. It then introduces quantum computers, explaining key concepts like quantum superposition, entanglement, and teleportation. Quantum computers could solve problems like factorization exponentially faster than classical computers. While promising for applications like encryption, simulation, and optimization, quantum computing faces challenges like difficulty controlling qubits and requiring isolated environments. The document envisions future work developing silicon-based quantum computers, new algorithms, and using quantum computers to simulate other quantum systems.

1. UANTUM Computing
By:Amrit Chandra
Roll no 15

2. OVERVIEW
• Introduction and History
a. Classical Computers
b. Quantum Computers
• Data Representation
• Conclusion and Scope

3. Evolution of Classical Computers
• First generation(1939-’54)-Vacuum tubes
• Second generation(1954-’59)-Transistors
• Third generation(1959-’71)- IC
• Fourth generation(1971-’91)- Microprocessor
• Fifth generation(1991 & beyond)

4. Comment on Classical Computer::
• Gordon Moore, Intel Co-founder said that the number of transistors economically
crammed into a single computer chip was doubling every two years.
Functions of Classical Computers
•Accurate and speedy computation machine
•Part of life because logical work can also be done

5. Advantages of Classical Computer
• Any complex computation or logical work like laboratory work
become easy
• Many kinds of numerical problems cannot be solved using
conventional computers.
• Example: Factorization of a number
• The computer time required to factor an integer containing N
digits is believed to increase exponentially with N.

6. Concepts of Quantum Computers..
 Introduction & History
Basic concept of quantum computer
 Applications
 Advantages
 Disadvantages and Problems
 Future work

7. What does "quantum" mean?
 The word "quantum", in quantum computer, originates from "quantum
mechanics," a basic theory in physics. In brief, on the scale of atoms and
molecules, matter behaves in a quantum manner.
INTRODUCTION
What is a Quantum Computer?
 A quantum computer is a machine that performs calculations based on the
laws of quantum mechanics, which is the behavior of particles at the sub-atomic
level.

8. HISTORY
• In 1918 - Max Planck’s -Energy quantum
• In 1921- Einstein’s discovery of the photon
• In 1980 - Idea of quantum computation
• In 1996, Grover’s came up with an algorithm to search a name in unsorted
database. Grover’s algorithm and the law of super-positioning makes this
possible.
• In December of last year, Anton Zeilinger made a fantastic accomplishment.
This feat was achieved using a principle called quantum entanglement.

9. Basic Concept Of Quantum Computers & Differences With Existing Computers:
• In existing computers, all information is expressed in terms of 0s and 1s, and the entity
that carries such information is called a "bit.“
• A bit can be in either a 0 or 1 state at any one moment in time.
• A quantum computer, on the other hand, uses a “quantum bit” or "qubit" instead of a bit.
• A qubit also makes use of two states (0 and 1) to hold information, but in contrast to a bit,
In this state, a qubit can take on the properties of 0 and 1 simultaneously at any one
moment.
• Accordingly, two qubits in this state can express the four values of 00, 01, 10, and 11 all
at one time .

10. A qubit in superposition is in both of the states
|1> and |0> at the same time.

11. Classical bit Vs Qubits:
• Classical bit: {0, 1}
• Qubits: {0, 1, superposed states of 0 and 1}

12. WHAT IS DIFFERENT ABOUT QUANTUM COMPUTERS?
Applications:
There is much that is different between quantum computers and classical computers.
But am going to explain only few:
1. Quantum Super Positioning
2. Quantum Entanglement
3. Quantum Teleportation

13. Quantum Superposition
• Super Positioning is a big word for an old concept: that two things can
overlap each other without interfering with each other.
• In classical computers, electrons cannot occupy the same space at the same
time, but as waves, they can.
• One may think of this as a vector of the probabilities drawn in a two-
dimensional coordinate system of the Complex plane, that is, coordinates of
the form x+iy where
• x is a coordinate on the Real number line, and
• y is a coordinate on the Imaginary number line.
• Classical bits are either vectors of 0 or 1 and have no Imaginary component.

14. •Quantum bits, or "qubits", have both components.
•If the probabilities were equal, the vector could be represented
as 45 degrees from vertical; if the probability of 1 were twice
that of 0, the vector could be represented as 30 degrees from
vertical.
•This vector represents the superposition of the probability of 1
and the probability of 0 simultaneously. In this way, the state
vectors of classical bits are "collapsed" qubit state vectors

15.  Entanglement is the ability of quantum systems to exhibit correlations
between states within a superposition.
 Quantum entanglement is one of the central principles of quantum physics,
though it is also highly misunderstood.
 In short, quantum entanglement means that multiple particles are linked
together in a way such that the measurement of one particle's quantum state
determines the possible quantum states of the other particles.
 When this happens, the state of the two particles is said to be entangled.
Quantum Entanglement

17. Quantum Teleportation
• Quantum teleportation is a technique used to transfer information on a
quantum level, usually from one particle to another.
• Its distinguishing feature is that it can transmit the information present in a
quantum superposition, useful for quantum communication and
computation.

18. Applications:
• Encryption Technology
• Ultra-secure And Super-dense Communications
• Improved Error Correction And Error Detection
• Molecular Simulations
• True Randomness
• Cryptography
• Searching
• Factorization
• Simulating
• Encryption Problem & Quantum Chemistry Problem

19. Advantages :
• Could process massive amount of complex data.
• Ability to solve scientific and commercial problems.
• Process data in a much faster speed.
• Capability to convey more accurate answers.
• More can be computed in less time.
• These are used to protect secure Web pages, encrypted email, and many
other types of data.

20.  Hard to control quantum particles
 Lots of heat
 Expensive
 Difficult to build
 Not suitable for word processing and email.
 Problem of it need of a noise free & Cool Environment.
 Complex hardware schemes like superconductors
Disadvantages and Problems:

21. • Silicon Quantum Computer
• It may become technology sooner than we expect
• At the current rate of chip miniaturization, energy efficiency, and economics, the
classical computer of the year 2020 (if it could happen at all), would contain a
CPU running at 40 GHz (or 40,000 MHz), with 160 GB (160,000 MB) RAM, and
run on 40 watts of power.
• New algorithms and communication
• Maximum exploitation
• Simulate other quantum systems.
Feature work :

22. Conclusion and Scope
 Very Advance Technology
 Very Faster & Powerful
 Stage of Infancy
 Implementation is Difficult