The document discusses quantum computing, detailing principles such as quantum superposition and entanglement, and comparing it to classical computing by highlighting the advantages of using qubits. Quantum computers can perform calculations exponentially faster due to their ability to handle multiple states simultaneously, facilitated by the rules of quantum mechanics. However, challenges such as technological limitations and environmental sensitivity of qubits hinder practical implementation, with ongoing research addressing these issues.

1. QUANTUM COMPUTING
--THE FUTURE IN PRESENT

2. CRITERION OF NORMAL COMPUTING
In normal computing,
• The size of a transistor ranges from 14nm, 500 times less then RBC’s (7µm).
• This resembles in accordance with Moore’s Law,
• Its states that “The number of transistors in a dense integrated circuit doubles about every two
years”.
• This was stated true till 2015.
• Later period, the counting of transistors shrunk down in doubles for every two years, experts told
that the size of a transistor can be shrunk up to 5nm more by much in increase it could lead to
quantum tunnelling.
• Quantum Tunneling: Mechanical phenomenon where a subatomic particle passes through a
potential barrier that it cannot surmount under the provision of classical mechanics.

3. PRINCIPLES OF QUANTUM COMPUTING:
QUANTUM SUPERPOSITION
QUANTUM ENTANGLEMENT

4. QUANTUM SUPERPOSITION
The principle of Quantum superposition states that
• If a physical system may be in one of many configurations—arrangements of particles or
fields—then the most general state is a combination of all of these possibilities, where the
amount in each configuration is specified by a complex number.
• Mathematically, it refer to the major theory proposed by Schrodinger known as
Schrodinger’s Cat theory.
• Schrödinger's cat: A cat, a flask of poison, and a radioactive source are placed in a
sealed box. If an internal monitor (e.g. Geiger counter) detects radioactivity (i.e. a single
atom decaying), the flask is shattered, releasing the poison, which kills the cat. The
Copenhagen interpretation of quantum mechanics implies that after a while, the cat
is simultaneously alive and dead. Yet, when one looks in the box, one sees the
cat either alive or dead, not both alive and dead. This poses the question of when exactly
quantum superposition ends and reality collapses into one possibility or the other.

5. QUBITS
• Quantum Computer process out the given data in the form of ‘1’
and ‘0’ in the form of qubits in the quantum processor.
• QUBITS: Quantum Bits.
• In normal computer, the speed depends on the number of transistors
present, the gigahertz of frequency, here it depends on the count of
qubits.
• May be a electron or a photon.
• Here switching of transistors corresponds to spin of a electron.
• Transistor ON : electron spins UP : binary count : ‘1’
• Transistor OFF : electron spins DOWN : binary count : ‘0’
• Spin is in dilemma of Schrodinger Cat theory, either 20% spin UP
and 80% spin DOWN (or) 80% spin UP and 20% spin DOWN.
• “The two states are perfectly correlated”.
• In the language of quantum mechanics, the two states are
“Entangled”.

6. QUANTUM ENTANGLEMENT
• It is a quantum mechanical phenomenon
in which the quantum states of two or
more objects have to be described with
reference to each other, even though the
individual objects may be spatially
separated.
• This leads to correlations between
observable physical properties of the
systems.
• Qubits can be entangled with one another,
which means that they can form the
superposition of their unique states.
• This can be related with Schrodinger’s
Cat Theory as well.

7. WORKING OF A QUANTUM COMPUTER
• The quantum computers work efficiently and it must be operated in controlled
magnetic field and operated at absolute zero temperature. Any external disturbances
to quantum computing or quantum computers may ruin the process.
• Eg: If you work like a classical computer, then in the worst-case scenario you'll have
to look the function up five times. That's because even if you see a 1 allocated to the
first 4 bit-strings you check, you still can't be sure that all the bit-strings come with a
1: there is still the possibility that it's only half of them, so you do need that 5th look-
up. If you have a quantum computer, however, you can get it to look up the function
value for all the eight people simultaneously, so you only need one look-up..

8. QUANTUM COMPUTING
ADVANTAGES
• Can execute any task very faster when compared
to the classical computer.
• In quantum computing, qubit is the
conventional superposition state and so there is
an advantage of exponential speedup which is
resulted by handle number of calculations.
• Classical algorithm calculations are also
performed easily which is similar to the classical
computer.
• Google has made a initiative to develop a
quantum computer ranging up to 72nm qubits
structure, which means 2^72 operations can be
done simultaneously
DISADVANTAGES
• Technology required to implement a quantum
computer is not available at present.
• The reason for this is the consistent electron is
damaged as soon as it is affected by its
environment.
• The research for this problem is still continuing
the effort,
• Application to identify a solution for this case
has no positive progress.

9. RELATIVITY WITH QUBITS
In the same way,
• When one qubit is ‘1’, the other qubit should always be ‘0’ (or)
• When one qubit is ‘0’, the other qubit should always be ‘1’.
• The performance of qubits is done by the following formula,
2^N
where N= number of qubits or electrons or photons.
So when N= 20,
2^20= 1,048,576 operations take place simultaneously.
APPLICATIONS:
o ARTIFICIAL INTELLIGENCE
o MOLECULAR MODELING
o CRYPTOGRAPHY
o FINANCIAL MODELING
o WEATHER FORECASTING
o PARTICLE PHYSICS

11. THANK YOU
BY: GAUTHAM.G
PRADEEP.B.M
DEPARTMENT OF ECE
KUMARAGURU COLLEGE OF TECHNOLOGY