Basic of Quantum Computing

1. Quantu
m
Comput
ing
Presented By -
Mr. Prathamesh Devkar
Mr. Suraj Bhujbal
Mr. Ganesh Pasnurwar

2. Agenda
• What is Quantum Computer
• Basic Quantum Information
• Superposition & Entanglement
• Quantum Gates

3. What is 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.

4. Why Quantum Computing ?
Process massive amount of complex data in very less time than classical computer.
It has ability to solve scientific and commercial problems, which never have even solved.
Process data in a much faster speed than classical Computer.
It has Capability to convey more accurate answers.

5. How Quantum Bit is different than Classical Bit
• In existing computers, all information is expressed in terms of 0's and 1's, 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.

7. Qubit Representation
<ψ| is a row vector known as bra
|ψ> is a column vector known as ket
Ket : |a> = a1 Bra : <b| = ( b1,b2 )
a2 <b| = |b>+ = b1
+
b2
Bra-Ket : <b|a> = a1b1
* + a2b2
* = <a|b>*
Ket-Bra : |a><b| = a1b1
* a1b2
*
a2b1
* a2b2
*

8. Multi Qubit Representation & Tensor Product
Two Qubit System
• Classical 2-bits are : 00,01,10,11.
• Quantum 2 qubit system is a linear superposition.

9. Superposition
• Classical bits can only be found in the states 0 and 1
• Qubit can represent the values 0 and 1, or linear
combinations of both.
• These linear combinations are known as superpositions.
• |ψ> = α|0> + β|1> ,where |α|2 +|β|2 =1

10. Quantum Entanglement
• Quantum entanglement is a phenomenon wherein the
quantum properties of two (or more) particles become
codependent, with the properties of one being
instantaneously affected by measurements conducted on
the other.
• Example : A pair of electrons having opposite spins, with
the actual spin of each particle remaining in a state of
quantum uncertainty .On the separation of the pair of
particles, even by a huge distance, and on measuring one
particle's spin the other particle's spin will automatically
resolve itself in the other direction. On the separation of
the pair of
This Photo by Unknown author is licensed under CC BY-NC-ND.

11. Interference
• Constructive interference - to increase
the probability of the correct answer.
• Destructive interference - to decrease
the probabilities of the
incorrect answer.

12. Bloch Sphere
The Bloch Sphere is a representation of a qubit, the fundamental building block of
quantum computers.
The most general state vector of a qubit can be expressed as
where θ is the polar angle and Φ is the az-imuthal angle of the unit vector in 3-d real
vector space.

13. Superposition States as Points on the Unit Sphere

14. Superposition States as Points on the Unit Sphere

15. Superposition States as Points on the Unit Sphere

16. Superposition States as Points on the Unit Sphere

18. Quantum
Gates
Quantum gates and circuits are
the quantum computing
counterparts to classical logic gates
and circuits, but with a dash of
quantum weirdness. In classical
computing, you manipulate bits
using logical gates like AND, OR,
and NOT. Quantum computing,
being the quantum rebel it is, uses
quantum gates to perform
operations on qubits

22. Thank You