Entanglement
<h1>Quantum Entanglement</h1>
<p>
<strong>Quantum Entanglement</strong> is one of the most fascinating and powerful phenomena in
quantum mechanics. It occurs when two or more qubits become linked in such a way that the
state of one qubit instantly influences the state of another, no matter how far apart they are.
</p>
<p>
This connection between qubits creates a shared quantum state that cannot be described
independently. Instead, the system must be treated as a whole.
</p>
<img src="https://mega.nz/file/GvgQXY5Q#Vkk8HvL0PU9W3ZMd_PORnrX-rK6Sy4ftqZ1q0tfGZ_0" width="500">
<hr>
<h2>Understanding Entanglement</h2>
<p>
When qubits are entangled, measuring one qubit immediately determines the state of the
other qubit.
</p>
<p>
For example:
</p>
<ul>
<li>If Qubit A is measured as <strong>0</strong></li>
<li>Then Qubit B will instantly become <strong>1</strong> (depending on the entangled state)</li>
</ul>
<p>
This happens even if the qubits are separated by thousands of kilometers.
</p>
<hr>
<h2>Mathematical Representation</h2>
<p>
One of the most common entangled states is called a <strong>Bell State</strong>.
</p>
<pre>
|Φ⁺⟩ = (|00⟩ + |11⟩) / √2
</pre>
<p>
This means the system exists in a superposition where both qubits are
simultaneously in states:
</p>
<ul>
<li>|00⟩</li>
<li>|11⟩</li>
</ul>
<p>
But once measured, both qubits collapse into one of these states together.
</p>
<hr>
<h2>Real Life Analogy</h2>
<p>
Imagine you have two magical coins that are entangled.
</p>
<ul>
<li>You send one coin to New York</li>
<li>You keep the other in Tokyo</li>
</ul>
<p>
If you flip your coin and get <strong>Heads</strong>, the other coin will instantly
show <strong>Tails</strong>, no matter how far apart they are.
</p>
<p>
This instant connection is similar to quantum entanglement.
</p>
<hr>
<h2>Creating Entanglement in Qiskit</h2>
<p>
In quantum programming, entanglement can be created using a combination of
<strong>Hadamard (H)</strong> and <strong>CNOT gates</strong>.
</p>
<pre><code class="language-python">
from qiskit import QuantumCircuit
# Create a circuit with 2 qubits
qc = QuantumCircuit(2)
# Step 1: Create superposition
qc.h(0)
# Step 2: Entangle qubits using CNOT
qc.cx(0, 1)
# Measure both qubits
qc.measure_all()
print(qc)
</code></pre>
<hr>
<h2>Applications of Quantum Entanglement</h2>
<ul>
<li>Quantum Teleportation</li>
<li>Quantum Cryptography</li>
<li>Quantum Networking</li>
<li>Quantum Algorithms</li>
</ul>
<hr>
<h2>Why Entanglement Matters</h2>
<p>
Entanglement allows quantum computers to create strong correlations between qubits,
which enables them to perform complex computations that are impossible for
classical computers.
</p>
<p>
It is one of the key reasons quantum computers have the potential to revolutionize
fields such as cryptography, drug discovery, and artificial intelligence.
</p>
<hr>
<h2>Conclusion</h2>
<p>
Quantum entanglement is a fundamental building block of quantum computing.
By linking qubits together in a shared quantum state, entanglement enables
powerful computational capabilities that go far beyond classical systems.
</p>