Quantum computing is a rapidly emerging technology that uses principles of quantum mechanics like superposition and entanglement to perform operations on quantum bits (qubits) and solve complex problems. It has the potential to vastly outperform classical computers for certain problems. The document discusses key aspects of quantum computing including how it differs from classical computing, what qubits are, how quantum computers work using elements like superconductors and Josephson junctions, and potential applications in areas like artificial intelligence, drug development, weather forecasting, and cybersecurity. It also covers advantages like speed and ability to solve complex problems, as well as current disadvantages like difficulty to build and susceptibility to errors.

1. Quantum computing

2.  INDEX
Introduction
Objective
Need of quantum computers
Difference between classical computers and
quantum computers
Methodology
What are Qubits
Application of quantum computing
Advantages & Disadvantages
Conclusion

3. INTRODUCTION
Quantum computing is an area of study focused on the
development of computer based technologies centered
around the principles of quantum theory.
Quantum computing is a rapidly-emerging technology that
harnesses the laws of quantum mechanics to solve problems
too complex for classical computers.
Quantum computers harness the unique behaviour of
quantum physics—such as superposition, entanglement and
quantum interference—and apply it to computing. This
introduces new concepts to traditional programming
methods.
Quantum computers operate on QUBITS (Quantum Bites)
which themselves are affected by quantum behavior-
Superposition and Entanglement.

4.  Objective
• Quantum computing is the study of how to use
phenomena in quantum physics to create new
ways of computing.
• Quantum computing is made up of qubits.
• Unlike a normal computer bit, which can be 0 or
1, a qubit can be either of those, or a
superposition of both 0 and 1.
• The power of quantum computers grows
exponentially with more qubits.
• This is unlike classical computers, where adding
more transistors only adds power linearly

5. Need for quantum computers
• Quantum computers can solve any computational problem that any classical computer can. , the
converse is also true that classical computers can solve all the problems of quantum computers too. It
means they provide no extra benefit over classical computers in terms of computability but there are
some complex and impossible problems that cannot be solved by today’s conventional computers in a
practical amount of time. It needs more computational power. Quantum computers can solve such
problems in reasonably and exponentially lower time complexities, also known as Quantum
Supremacy
• Peter Shor in 1993 showed that Quantum computers can help to solve these problems considerably
more efficiently like in seconds without getting overheated. He developed algorithms for factoring
large numbers quickly. Since their calculations are based on the probability of an atom’s state before it
is actually known. These are having the potential to process data in an exponentially huge quantity. It
also explains that a practical quantum computer could break the cryptographic secret codes. It can risk
the security of encrypted data and communication. It can expose private and protected secret
information. But the advantages of quantum computers are also kept in mind that is significantly more
than its flaws. Hence, they are still needed and further research is going towards a brighter future

6. Conventional Computing Quantum Computing
Conventional computing is based on the classical
phenomenon of electrical circuits being in a single state at a
given time, either on or off.
Quantum computing is based on the phenomenon of
Quantum Mechanics, such as superposition and
entanglement, the phenomenon where it is possible to be in
more than one state at a time.
Information storage and manipulation is based on “bit”, which
is based on voltage or charge; low is 0 and high is 1.
Information storage and manipulation is based on Quantum
Bit or “qubit”, which is based on the spin of electron or
polarization of a single photon.
The circuit behavior is governed by classical physics.
The circuit behavior is governed by quantum physics or
quantum mechanics.
Conventional computing use binary codes i.e. bits 0 or 1 to
represent information.
Quantum computing use Qubits i.e. 0, 1 and superposition
state of both 0 and 1 to represent information.
CMOS transistors are the basic building blocks of conventional
computers.
Superconducting Quantum Interference Device or SQUID or
Quantum Transistors are the basic building blocks of quantum
computers.
In conventional computers, data processing is done in Central
Processing Unit or CPU, which consists of Arithmetic and Logic
Unit (ALU), processor registers and a control unit.
In quantum computers, data processing is done in Quantum
Processing Unit or QPU, which consists of a number of
interconnected qubit

7. Literature survey
S.NO Name of paper author explenation Year of
publication
Simulating Physics with
Computers
Richard P. Feynman 1982
The Impact of Quantum
Computing on Present
Cryptography
Mateusz D. Zych,
Audun Jøsang
The aim of this paper is to elucidate the implications
of quantum computing in present cryptography and
to introduce the reader to basic post-quantum
algorithms.
2018
Quantum Computing: Future
Computing
Vishal Gotarane
advantages they offer us in compare with the
classical
computers.
challenges to Quantum computin
| Feb-2016
Basic study of quantum computer
vs classical computers
Dr.Ritushree
Narayan
Distinction between quantum computer and classical
computer
June 2020

8. What is a
qubit?
• A qubit is a quantum bit, the counterpart in quantum
computing to the binary digit or bit of classical
computing. Just as a bit is the basic unit of information
in a classical computer, a qubit is the basic unit of
information in a quantum computer.
• In a quantum computer, a number of elemental
particles such as electrons or photons can be used (in
practice, success has also been achieved with ions),
with either their charge or polarization acting as a
representation of 0 and/or 1. Each of these particles is
known as a qubit; the nature and behavior of these
particles (as expressed in quantum theory) form the
basis of quantum computing. The two most relevant
aspects of quantum physics are the principles
of superposition and Entanglement

9. BITS QUBITS
1.
The device computes by manipulating those bits with the
help of logical gates (AND, OR, NOT).
The device computes by manipulating those bits with
the help of quantum logic gates.
2.
A classical computer has a memory made up of bits where
each bit hold either a one or zero.
A qubits (quantum bits) can hold a one, a zero or
crucially a superposition of these.
3. Bits are used in classical computers. Qubits(Quantum bits) are use in quantum computer
4.
Information is stored in bits, which take the discrete values 0
and 1.
Information is stored in quantum bits, or qubits. A
qubit can be in states labelled |0} and |1}, but it can
also be in a superposition of these states, a|0} + b|1},
where a and b are complex numbers. If we think of
the state of a qubit as a vector, then superposition of
states is just vector addition.
5.
For example, if storing one number takes 64 bits, then
storing N numbers takes N times 64 bits.
For example, for every extra qbit you get, you can
store twice as many numbers. For example, with 3
qubits, you get coefficients for |000}, |001}, |010},
|011}, |100}, |101}, |110} and |111}.
6. Bits are slow. Qubits are faster.
7. Its circuit behavior based on classical physics. Its circuit behavior based on quantum mechanics.

10. How do
quantum
computers
work?
• A classical processor uses bits to perform its operations. A quantum
computer uses qubits (CUE-bits) to run multidimensional quantum
algorithms.
• Superfluids
Your desktop computer likely uses a fan to get cold enough to work.
Our quantum processors need to be very cold – about a hundredth of
a degree above absolute zero. To achieve this, we use super-cooled
superfluids to create superconductors.
• Superconductors
At those ultra-low temperatures certain materials in our processors
exhibit another important quantum mechanical effect: electrons
move through them without resistance. This makes them
"superconductors." When electrons pass through superconductors
they match up, forming "Cooper pairs." These pairs can carry a charge
across barriers, or insulators, through a process known as quantum
tunneling. Two superconductors placed on either side of an insulator
form a Josephson junction

11. • Control
quantum computers use Josephson junctions as superconducting
qubits. By firing microwave photons at these qubits, we can control
their behavior and get them to hold, change, and read out individual
units of quantum information.
• Superposition
A qubit itself isn't very useful. But it can perform an important trick:
placing the quantum information it holds into a state of superposition,
which represents a combination of all possible configurations of the
qubit. Groups of qubits in superposition can create complex,
multidimensional computational spaces. Complex problems can be
represented in new ways in these spaces.
• Entanglement
Entanglement is a quantum mechanical effect that correlates the
behavior of two separate things. When two qubits are entangled,
changes to one qubit directly impact the other. Quantum algorithms
leverage those relationships to find solutions to complex problems

13. Artificial Intelligence & Machine Learning
• Artificial intelligence and machine learning are some of the prominent areas right now,
as the emerging technologies have penetrated almost every aspect of humans’ lives.
• Some of the widespread applications we see every day are in voice, image
and handwriting recognition. However, as the number of applications increased,
it becomes a challenging task for traditional computers, to match up the accuracy and
speed. And, that’s where quantum computing can help in processing through complex
problems in very less time, which would have taken traditional computers thousands of
years.

14. Drug Design &
Development
• Designing and developing a drug is the most challenging
problem in quantum computing. Usually, drugs are being
developed via the trial and error method, which is not only
very expensive but also a risky and challenging task to
complete.
• Researchers believe quantum computing can be an
effective way of understanding the drugs and its reactions
on humans which, in turn, can save a ton of money and
time for drug companies. These advancements
in computing could enhance efficiency dramatically, by
allowing companies to carry out more drug discoveries
to uncover new medical treatments for the better
pharmaceutical industry.

15. Cybersecurity
&
Cryptography
• The online security space currently has been quite
vulnerable due to the increasing number of cyber-attacks
occurring across the globe, on a daily basis. Although
companies are establishing necessary security framework
in their organizations, the process becomes daunting and
impractical for classical digital computers. And, therefore,
cybersecurity has continued to be an essential concern
around the world.
• With our increasing dependency on digitization, we are
becoming even more vulnerable to these threats.
Quantum computing with the help of machine learning
can help in developing various techniques to combat these
cybersecurity threats. Additionally, quantum computing
can help in creating encryption methods, also known as,
quantum cryptography.

16. Currently, the process of analyzing weather conditions by traditional computers can
sometimes take longer than the weather itself does to change. But a quantum
computer’s ability to crunch vast amounts of data, in a short period, could indeed
lead to enhancing weather system modelling allowing scientists to predict the
changing weather patterns in no time and with excellent accuracy something which
can be essential for the current time when the world is going under a climate
change.
Weather Forecasting

17. Advantages of
Quantum
Computing
• They’re fast. Ultimately, quantum computers have the potential to
provide computational power on a scale that
traditional computers cannot ever match. In 2019, for example, Google
claimed to carry out the calculation in about 200 seconds that would
take a classical supercomputer around 10,000 years.
• They can solve complex problems. The more complex a problem, the
harder it is for even a supercomputer to solve. When a classical
computer fails, it’s usually because of a huge degree of complexity and
many interacting variables. However, due to the concepts of
superposition and entanglement, quantum computers can account for all
these variables and complexities to reach a solution.
• They can run complex simulations. The speed and complexity that
quantum computing can achieve means that, in theory, a quantum
computer could simulate many intricate systems, allowing us to better
understand some of life’s great mysteries.

18. Disadvantages of quantum computing
• They’re difficult to build. As we saw with IBM’s Quantum System One, a functional quantum
computer needs a very specific set of conditions to operate. They require unique components,
massive cooling systems, and expensive technology to run at even a basic level.
• They’re prone to errors. Due to the nature of quantum mechanics and qubits, environmental
factors can soon produce errors and lose their quantum state a process known as
decoherence. These errors multiply with levels of complexity, which means that to reach
their potential, a solution for error correction is needed.
• They’re only suitable for specific tasks. As we’ll see, quantum computers have the potential
to deliver revolutionary solutions in some specific areas. However, due to the nature of how
they work, they’re not expected to offer advantages in all areas of computing.

19. conclusion
• Quantum computers have the potential to revolutionize
computation by making certain types of classically intractable
problems solvable. While no quantum computer is yet
sophisticated enough to carry out calculations that a classical
computer can't, great progress is under way
• The field of quantum computing is still in its infancy. As we’ve seen,
the technology is still imperfect and hard to harness, with many
unknowns. However, the current and potential uses of quantum
computers could change the way we understand the world around
us.
• From detailed models and simulations to significantly faster
problem solving, quantum computers have significant potential.
However, whether or not we can fully realise that potential remains
to be seen. Companies such as Google and IBM are heavily invested
in the technology, so if nothing else, we can expect to see further
advancements in the coming years. This Photo by Unknown author is licensed under CC BY-SA.

20. Reference
• Fastovets, Dmitriy V., et al. "Machine learning methods in quantum
computing theory." International Conference on Micro-and Nano-
Electronics 2018. Vol. 11022. SPIE, 2019.
• Introduction to Quantum Computing-
• https://www.ibm.com/topics/quantum-computing
• https://refreshscience.com/quantum-computing-101
• Quantum computing
• https://en.wikipedia.org/wiki/Quantum_computing
• Vepsäläinen, Antti P.; Karamlou, Amir H.; Orrell, John L.; Dogra,
Akshunna S.; Loer, Ben; et al. (August 2020). "Impact of ionizing
radiation on superconducting qubit coherence". Nature. 584 (7822):
• Feynman, Richard (June 1982). "Simulating Physics with
Computers" (PDF). International Journal of Theoretical
Physics. 21 (6/7): 467–488. Bibcode:1982IJTP...21..467F.