What is the meaning of Quantum?
The name Quantum originates from the scientific term ‘Quantum,’ which refers to the smallest indivisible unit of energy or matter.
Quantum, deals with the Granular and Fuzzy nature of the universe and the physical behaviour of its smallest particles.
The idea of physical granularity is like the TV image. If we zoom in on the image, we see it is made of individual pixels. The Quantum world is similar. If we zoom in on the details of matter, we eventually see elementary units of matter and energy with their own unique characteristics.
For example:
- A photon is a Quantum of light.
- An Electron’s Spin is a Quantum property.
- Energy in atoms is transferred in quantized packets.
In Physics, it refers to the smallest packets of energy or matter. Quantum science deals with particles like electrons or photons that behave differently than things we see in daily life. These particles can do strange things like be in two places at once (superposition) or be connected across distances (entanglement).
What is Quantum Physics?
Quantum Mechanics is the science that explains how very tiny things (atoms and subatomic particles) behave. It’s the foundation of modern technologies like lasers, MRI machines, and soon, Quantum computers, Quantum internet, Quantum Electricity. Unlike classical physics, Quantum mechanics deals with probabilities and wave-like behaviours.
What are Bits?
In computing technology, a bit is the smallest unit of information measurement. It is also called a classical bit. Basically, Bit is the acronym for Binary Digit. Therefore, a bit is nothing but a binary 0 or a binary 1.
Bits are used to express information in all digital computing systems
What is Quantum Bits?
Quantum Bit is the smallest unit of information measurement in Quantum computing. It is also called Qubit. Unlike, classical bits, a Quantum bit can have multiple states at the same time. This property of Qubits is known as superposition.
– 0
– 1
– Or both at the same time (called superposition)
Mathematical Expression:|ψ⟩ = α|0⟩ + β|1⟩
Where α and β are probabilities (arbitrary Algebraic Complex Numbers) and must satisfy:
|α|² + |β|² = 1
This ability to be in multiple states makes Qubits powerful.
Difference between Bits and Qubits in Quantum Computing
| BITS | QUANTUM BITS |
| 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. |
| 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. |
| Bits are used in classical computers. | Qubits(Quantum bits) are use in Quantum computer |
| 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. |
| For example, if storing one number takes 64 bits, then storing N numbers takes N times 64 bits. | For example, for every extra qubit 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}. |
| Bits are slow. | Qubits are faster. |
| Its circuit behaviour based on classical physics. | Its circuit behaviour based on Quantum mechanics. |
What is Quantum Internet?
Quantum Internet is a futuristic version of today’s internet where information is transmitted using Qubits instead of classical bits. It uses principles of Quantum mechanics to ensure super-fast and ultra-secure communication.
Why the Name Quantum Internet
The Quantum Internet uses Quantum particles (like photons) instead of classical bits to transmit information.
It’s called “Quantum” Internet because it is based on Quantum mechanics, which allows strange but powerful features like:
- Entanglement: Two particles share a state even when far apart.
- Superposition: A particle can be in multiple states at once.
- No-cloning: You cannot copy a Quantum state exactly.
So, instead of sending 0s and 1s, the Quantum internet sends Qubits, which can be both 0 and 1 at the same time—allowing new types of communication like Quantum teleportation and unbreakable encryption
How Does Quantum Internet works
In the Quantum internet, information is encoded in Quantum bits, or Qubits, which can exist in multiple states at once thanks to a property called superposition. This allows the Quantum internet to transmit and process information in ways that are impossible with the classical internet. One of the key components of the Quantum internet is Quantum entanglement, a phenomenon in which two Qubits become linked in such a way that the state of one qubit instantly affects the state of the other, no matter the distance between them. This allows for secure communication channels that are immune to eavesdropping, making the Quantum internet ideal for sensitive data transmission.
Explanation of all Components used including Repeater, Router etc.
- Quantum Encoder: A device that encodes Data into Logical Qubits using Quantum error correcting Codes. Protects Quantum Information from noise and de coherence.
- Entanglement Source / Qbit Generator: Creates Entangled pairs of Qubits shared between distance Nodes ( Users or Repeaters )
- Quantum Router/Switch: Directs the Quantum data to the right destination.
- Quantum Channel (Fibre/Satellite): Carries Quantum data using light.
- Quantum Repeater: Boosts the signal and maintains entanglement.
- Quantum Computer or Device: Receives and processes the Quantum data.
Working Process of Quantum Internet
- User a Sends Data
- A qubit is generated.
- It’s sent through a Quantum channel.
- Quantum repeaters maintain entanglement.
- Data arrives at the Quantum receiver.
- Any interception disturbs the state, signalling eavesdropping
Data Store:
- Quantum Memory at Repeater Nodes
- Classical Buffer for Measurement Data
Quantum Internetworking principle with Quantum Mechanics:
The Quantum Internet leverages principles of Quantum mechanics such as Superposition,
Entanglement, and Quantum teleportation to enable ultra-secure communication. Unlike
Classical internet, it uses Qubits that can exist in multiple states simultaneously, making it
Faster and more secure
What is Entanglement?
It is a phenomenon where 2 or more Qubits become linked such a way that the State of one instantly influences the state of the other, no matter how far they are in space.
Quantum entanglement is a mysterious connection between two particles, even if they are far apart — like one in London and the other on the Moon. If we do something to one particle, the other particle reacts instantly, no matter how far apart they are. It’s like they’re magically linked or “Entangled.”
If one dice rolls a 6, the other automatically rolls a 6, even if it’s on the other side of the world.
What is superposition?
A Qbit exists in multiple states simultaneously.
What is Teleportation?
It is a way to send the State of a Qbit (Quantum Information) from one place to other without sending the Physical Qubits
Let’s clarify with an Example
- You (Alice) have a secret colour (Quantum state).
- You want to send it to your friend (Bob), who is far away.
- But the rule is: you can’t send the actual object with the colour.
So, what do to do?
- Alice and Bob already share a magic link (entangled qubit pair).
- Alice measure your colour and his part of the magic link together.
- Alice get a result (2 bits of classical info).
- Alice send just the result (via normal internet) to Bob.
- Bob uses that info to apply a trick (Quantum operation) on his part of the magic link.
Bob’s object now has your exact original colour, even though it never physically travelled.
What is the meaning of IBM 1121 Qubits Processor?
- A Quantum processor with 1121 Qubits has 1121 Quantum bits available for computation.
- Theoretically, the computational power doubles with each additional qubit. So 1121 Qubits can, in principle, represent (2^1121) states simultaneously — an astronomically large number.
Relation of Schrödinger Equation and Hamilton Operator to Quantum Internet
The Quantum Internet is based on the principles of Quantum mechanics and utilizes Quantum bits (Qubits) for communication. Two key components of Quantum theory—Schrödinger’s Equation and the Hamiltonian operator—play fundamental roles in understanding how Quantum states evolve within Quantum networks.
The Schrödinger Equation describes the time evolution of a Quantum state:
Schrödinger Equation with Hamilton Operator in Quantum Physics
Here:
– |ψ(t)⟩ is the Quantum state of the system (such as a qubit).– Ĥ is the Hamiltonian operator (total energy of the system).– ħ is the reduced Planck constant.
-I is the square Root of Negative 1 used in complex Number
In the Quantum Internet, Qubits transmitted between nodes evolve according to this equation. This governs how information is preserved or altered across Quantum channels.
2. Role of the Hamiltonian Operator and Schrödinger Equation
The Hamiltonian operator Ĥ defines the energy of a Quantum system and how different components (such as Qubits and photons) interact. In Quantum networking, the Hamiltonian includes terms for:
– Qubit-photon interactions
– Entanglement generation
– Quantum Gate Operations
– Environmental de coherence.
-The Probability Amplitudes evolves.
In summary:
- The Hamiltonian Operator tells us how the quantum system behaves during transit.
- The Schrödinger equation describes how the system evolves and reacts to external interference (like eavesdropping).
These dynamics are critical when simulating or implementing Quantum communication protocols.
3. Practical Example: Quantum Teleportation
During Quantum teleportation:
– An entangled pair of Qubits is shared between sender and receiver.
– The sender’s operations evolve under a local Hamiltonian.
– The receiver reconstructs the Quantum state based on classical and Quantum information.
The Schrödinger equation governs the state evolution during each step, with the Hamiltonian determining interactions and energy transitions.
Security in Quantum Internet
Quantum Key distribution ( QKD)
- Most mature Quantum security application.
- Allows two parties to share a secret cryptographic key with provable security.
- Based on Quantum entanglement or single photons.
- Eavesdropping is detectable due to the no-cloning theorem and measurement disturbance.
�� Protocols:
- BB84 – First and most famous protocol.
- E91 – Based on entanglement (Ekert protocol).
- Measurement-device-independent QKD (MDI-QKD) – Prevents side-channel attacks.
Post Quantum Cryptography Vs Quantum Cryptography
- Post-Quantum cryptography: Classical algorithms resistant to Quantum attacks (e.g., lattice-based cryptography).
- Quantum cryptography: Uses Quantum mechanics itself for security (like QKD).
�� Quantum Internet favours the latter, ensuring unbreakable encryption regardless of future computational power.
Eavesdropping Detection
·Any attempt to intercept a Quantum transmission alters the state of the Quantum bits (Qubits).
·This allows the sender and receiver to detect tampering or the presence of an intruder.
Entanglement Based security
· Utilizes Quantum entanglement between distant nodes.
· provides a basis for device-independent security, i.e., even if your device is untrusted, security can still be ensured.
Quantum Repeater & Trusted Nodes
·Today’s QKD works well over short distances (~100–200 km).
·Quantum repeaters will eventually allow long-distance secure communication without trusting intermediate nodes.
·Until then, trusted nodes are used—intermediate points that decrypt and re-encrypt the key securely.
Application & Future Scope:
| Quantum Communication: | Ultra-secure internet, Quantum Key Distribution (QKD), military and diplomatic communication |
| Quantum Computing: | Solving complex simulations in drug discovery, materials science, cryptography |
| Quantum Sensing | :High-precision navigation (GPS-independent), magnetic field and gravitational sensors |
| Quantum Cryptography | : Unhackable data encryption using entangled photon-based keys |
| Quantum Networks: | Quantum cloud services, linking quantum computers across distances |
Quantum Electricity: Quantum Conductor and Quantum Transport, super conductivity, Electron Tunneling and quantum Dots, Topological Insulator and Quantum Hall effect.
Time Line to Launch:
India to Launch in 2027 -30
Company working:
TCS
ISRO
IIT Delhi / Madras
DRDO
CDAC
Author:
Debojit Maitra
Contact: 79779 96217