This document provides an overview of quantum computing. It discusses key concepts like qubits, superposition, and entanglement. Qubits can exist in superposition of states |0> and |1> allowing quantum computers to perform multiple calculations in parallel. Entanglement links the states of qubits. The document also covers applications in artificial intelligence and cybersecurity. Quantum cryptography uses principles of quantum mechanics for encryption but has limitations like short communication ranges and high costs.

1. Quantum
Computing
-Manmeet Singh

2. CONTENTS
1. What is Quantum Computing?
2. Main Processes
3. Qubits
4. Superposition
5. Representation Of Data
6. Entanglement
7. Why is it a Game Changer?
8. Applications
9. Quantum Cryptography
10. Quantum Tunneling
11. Laws Involved in Cryptography
12. Limitations Of Quantum Cryptography
13. References

3. What is Quantum Computing?
Quantum computing is basically
an idea evolved out of math,
computer science and physics.
Quantum computing is governed
by laws of quantum mechanics
which help us understand the
behavior at microscopic or
subatomic level.

4. Main concepts involved in
quantum computer:
• Quantum Bits
• Superposition
• Entanglement
• Quantum Tunneling

5. QUBITS
● A bit of data is represented by a single
atom that is in one of two states |0> or
|1>. A single bit of this form is known as
a qubit
● Quantum computers make use of qubits,
which are typically subatomic particles such
as electrons or photons.
● Qubits have some quirky quantum
properties like entaglement.
● Which means a group of them can provide
much more processing ability

6. Quantum Superposition
● Benefits of quantum superposition
○ Parallelism
○ Not just fast, it provides more
parallel
computational power
● A qubit can exist in 3 states
1. Spin up
2. Spin down
3. Superposition of both 0 and 1
states

7. Representation of Data - Superposition
• A single qubit can be forced into a superposition of the two states denoted by the addition of
the state vectors.
• A qubit in superposition is in both of the states |1> and |0 at the same time
• Basically initially when magnetic field is applied the qubit aligns in 0 state in which its
magnetic moment aligns parallel to applied field so as to achieve stable state.
• Using correct frequency photon pulses we can push the qubit to achieve the highest energy
state or unstable equillibrium ie 1 state
• However if we stop emitting pulse in middle it may lead to the fact that qubit exist in the
between both states as a superposition of both states.

8. Quantum Entanglement
Quantum Entanglement is the
phenomenon that does not allow two
particles to exist side by side
independently or it’s the process by
which altering state of one particle
alters the state of all nearby particles.
This is what makes a system of qubits
interconnected and efficient.

9. Why is it a Game Changer?
1. Quantum computers increase flexiblity since u have
much more storage hence much more flexible use and
storage of data.
2. Perform multiple task simultaneously,hence faster.
3. Quantum computers reduce power consumption.
4. Can solve unsolvable problems like breaking difficult
encryptions,analyzing huge data sets where u have to
make decisions analyzing large datas.
Quantum Computing works better in the
situations where we have to analyze a huge
set of outcomes and make decisions.

10. Quantum Tunneling

11. APPLICATIONS OF QUANTUM COMPUTING
 Present
• Bristlecone, by Google (Boasts of 72 qubits)
• Q System, by IBM (Uses 49 qubits)
• D - Wave 2000Q, Goldman Sachs (a quantum annealing system with 2000
qubits and adv. feature controls)
 Future uses
• Artificial Intelligence (Optimising search through gigantic datasets)
• Cybersecurity (Breaking Encryption)

12. Quantum Cryptography
• Cryptography is a method of protecting
information and communications through
the use of codes, so that only those for
whom the information is intended can
read and process it.
• In cryptography our text is converted into
cipher text using a private key. This
process is called encryption.
• The cipher text and key is sent to the
other entity and converted to normal
text. This process is called decryption.
The key is usually a string of binary digits.

13.  QUANTUM CRYPTOGRAPHY IS BASED ON QUANTUM PHYSICS AND
RELIES ON THE DIFFERENT LAWS OF QUANTUM MECHANICS.
The main two rules on which quantum cryptography relies are:
Heisenberg’s Uncertainty
Principle
Polarization

14. Limitations of Quantum Cryptography
Communication Range
Applicable over small
distances. Increasing it
causes channel loss
High Cost
As of now QKD
requires expensive
equipments.
Research is going on
to miniaturize it.
Requires New System
QKD requires physical
equipments which
makes it difficult to
integrate in current
systems.

15. REFERENCES
● https://www.explainthatstuff.com/quantum-computing.html
● http://spark.spit.ac.in/index.php/2017/11/22/geekonic-quantum-
computinghttp://www.physics.org/article-questions.asp?id=124
● https://www.quantiki.org/wiki/quantum-gates
● https://www.ibm.com/quantum-computing/what-is-quantum-computing/